Celestial Navigation in SH4 [Archive] - SUBSIM Radio Room Forums

6SJ7GT

04-16-08, 04:37 PM

UPDATE:
I have place the tools for this in the SH4 Gameplay Mods on this site.
look for the SH4 Nav Package (http://www.subsim.com/radioroom/downloads.php?do=file&id=2991)

Over in the real navigation thread in SH4 Mods, we have put together a working method of using celestial navigation in SH4. This is more of a hybrid than a mod, as it only uses Thendashes no sub on map mod (http://files.filefront.com/No+sub+on+map7z/;9399117;/fileinfo.html), and takes the sub position in a saved game and transfers it to a freeware planetarium program.

There is a tutorial here (http://www.filefront.com/user/6sj7gt) if you want to try celnav out.

I have put together the Almanacs and tools needed for plotting in a 7zip here (http://www.filefront.com/user/6sj7gt).

Below is the readme giving a description of what is involved in getting this working.

This is not a game mod. It works by taking the sub position from a saved game and inserting it blindly into a Planetarium program, where you take your star sights. Don1Reed has extensively tested this and found it to be very accurate. For me, it was a quest to use celestial navigation as it should be used.

Thendash has a small mod to remove the sub marker from the map in SH4 that greatly enhances this package. I have included it in the package with his permission. You can also find the "No Sub On Map" mod here:
http://files.filefront.com/No+sub+on+map7z/;9399117;/fileinfo.html

***** Update *****
The program sh4tostellarium.exe uses command line arguments to put the sub position into stellarium, you don't need to install Python for this. see the sh4tostellarium readme. I have added it to the full package and also uploaded just the program here.

Make sure you get the right program for the version of Stellarium that you are using.

SH4 to Stellarium program (http://www.filefront.com/user/6sj7gt).
******************

This package requires the installation of the freeware Planetarium Stellarium and Python open source programming language. . Stellarium is a worthwhile program in itself, and python is a powerful yet fairly easy to use scriptbased programming language. There are numerous tutorials and prebuilt python modules available on the net. I used the pyephem module to create the Almanac pages in Excel.

If you are not familiar with Celestial Navigation, there is a tutorial using a simplified method and the USNO Online Almanac. You can try this with Stellarium if you just want to try celnav.

To Implement this:
1. Install Stellarium: www.stellarium.org (http://www.stellarium.org)

2. Install Python, this version has the windows extensions: Activestate Python (http://www.activestate.com/store/activepython)

3. After installing start Stellarium so it creates a config.ini file. There should be a link to this in the Stellarium startup directory, if not you can find it under C:\Documents and Settings\***Your login name***\Stellarium.

Open this file and find the [localization] section. Change time_zone to =utc
Save and Close.

4 Put the SH4toStellarium.py script where you can find it. I created a shortcut to it on my desktop, along with a shortcut that runs Stellarium. You have to change a couple of lines in the script to reflect the directories you want. They are marked in the script.

Now run the game. go to the game screen before saving the game. I always save the game to a "Checknav" savegame so the directory stays the same. Note the time you save the game.

You have to convert the game time, which is the time at your base, to GMT.
(GMT is Pearl time + 10 hrs)

After saving the game, run the script, it will ask for the GMT date and time.

Now run Stellarium. it should start at the sub date, time and location. The tutorial has the info in taking "sights" and you are on your way to navigating independently.

The Files in this Archive:

Green TSD.pdf - Time-Speed-Distance sliderule.

Nomograph.pdf - Printable nomograph.

SH4toStellarium.py - Python script (text script).

Time Charts.pdf - Printable GMT conversion charts, use the one you like best.

ups.pdf Universal 8.5 X 11 Plotsheet courtesy of reedsalmanac.com

Short Tutorial on SH4 Celestial Navigation.pdf - The tutorial.

1942 thru 1945 Nautical almanacs - Sun and Star information for reducing sights. see Henning Umland's site www.celnav.de (http://www.celnav.de) for instructions on using Ageton's tables (compact.zip on his freeware page) plus lots of other info on celestial navigation.

HO-249 Star Sight Wksht for using the HO-249 tables (link in the Tutorial links pages).

sh4tostellarium.exe - program to create startup.sts for stellarium

sh4tostellarium readme.txt - instructions for sh4tostellarium.exe.

Fair skys and smooth sailing,
6SJ7GT / Mike

Edit 12/14/2009 to update links

6SJ7GT

04-20-08, 11:49 AM

Here is another version of the circular Time Speed Distance computer. You can print this out on cardstock to use in the game.

TSD Circular computer (http://files.filefront.com/tsd+circ+sliderule+ydspdf/;10043993;/fileinfo.html)

For those who have never used this:
You line up the arrow with your speed on the outer wheel, then you can read time (hours) on the inner wheel vs distance on the outer wheel.

EXAMPLE
line up the arrow (1) with 22(kts), this is also 44000yds/hr. In 1/2 hr you will travel 11 mi or 22000 yards. in 34 hrs you will travel approx. 750 mi.

If you line up the 6 on the inner wheel with your speed, you can read the time in minutes, as the wheel repeats. 6~60~600...
Line up the 6 (60) with 8 kts. In 22 minutes you will travel approx 2.9 mi (5900 yds). You will travel 14 mi in 105 minutes.

Enjoy,
Mike

Doolan

04-20-08, 03:57 PM

:o

This is genius!

Schultzy

04-22-08, 02:30 PM

i really love this but i find that the sub marker still flashes every 5 or so seconds on the map screen (i know it's there zoomed in) I mean when zoomed out. Does anyone else have this problem and is there any way to remove it completely?

Thanks for all the hard work though, this has added a whole new dimension. You're turning me into a navigation addict.

Doolan

04-22-08, 06:54 PM

You're turning me into a navigation addict.

Glad to see I'm not alone!

Guess who just purchased a cheap plastic training sextant... :lol:

6SJ7GT

04-22-08, 11:07 PM

Hello everyone,
It's good to see this getting some use.

i really love this but i find that the sub marker still flashes every 5 or so seconds on the map screen

Schultzy, I have the pulsating pixel too, but just continue to plot and navigate manually. it no longer bothers me as it just confirms the accuracy of this for me.

Doolan, Thanks for the compliment. Check out the REAL NAVIGATION (http://www.subsim.com/radioroom/showthread.php?t=116170&page=7) thread in SH4 Mods, Don1Reed has a lot of information on nevigation in general starting on page 7, and could explain the use of an artificial horizon to use with your sextant if you're landlocked and need help.

Mike

6SJ7GT

04-22-08, 11:10 PM

Here are some more goodies for use in navigating, I made some charts for the general operating area. They are small for plotting LOP's, but work good for keeping track of where you are if you are navigating manually.

Navigation Charts (http://files.filefront.com/SH4+Nav+Charts7z/;10062015;/fileinfo.html)

Mike

don1reed

04-23-08, 08:30 AM

I used to have a problem with the "no_sub_on_map" mod also...

until I did a complete, clean, reinstall with both SH3 and SH4.

I use 6SJ7GT's Real Navigation with both sims, SH3 & SH4. Both are working flawlessly.

I've been using Celestial Navigation for over 30 years. This new wrinkle for navigation gives me the opportunity to continue on while beached for good and without the hazard of drowning. lol. Great job, Mike.

Schultzy

04-23-08, 07:59 PM

Thanks for the replies!

I'm glad it's not just me imagining things! I've been trying to look at it as my subordinates showing me their estimates of where we are... The problem is, they seem to be better at it than I am! :lol:

Anyway, I shall try the re-install and see how that works out for me.

don1reed

04-24-08, 06:44 AM

another thing you could try, although tedious, is to open & run SH3 each time you reinstall a mod...maybe...just maybe, one of them may be causing a conflict and/or glitch thats causing your problem. Its the only way I know to zero in on a possible culprit.

All the best,

6SJ7GT

05-01-08, 09:19 PM

To All,
My son made a program out of the Python Script. You dont have to install Python, just run the program with command line options to set the directories. I added it to the Celestial Nav package, and uploaded the program separately.

Almanacs and tools for this in an archive here (http://files.filefront.com/Celestial+Navigation+for+H47z/;10116854;/fileinfo.html).

Just the program Here (http://files.filefront.com/sh4tostellarium7z/;10116866;/fileinfo.html).

I think I this is ready for a release tag in the mods forum.

Mike

6SJ7GT

05-23-08, 06:41 PM

To All,

I corrected a few errors to the almanacs, the 1941 to 1945 Nautical almanacs are at this link.
http://hosted.filefront.com/6sj7gt/2231663

I have been doing my navigating by the sun and stars with these. Usually I work up a sight then transfer my position to one of these nav charts.
http://files.filefront.com/SH4+Nav+Charts7z/;10062015;/fileinfo.html

Usually I get several days worth of sights on a plot sheet. I also figured out how to put the nav chart on the table in the control room.

http://users.ameritech.net/mjones004/Nav_Station.jpg

Have fun,
Mike

6SJ7GT

11-30-08, 04:06 PM

To All,
I finally added the 1939 and 1940 almanacs for SHIII per a request from Pisces.

You can find the 1939 thru 1945 almanacs at this link;
http://hosted.filefront.com/6sj7gt/2231663

Enjoy,
Mike

panzerschutze12ss

01-10-09, 09:34 PM

I'm having a problem with your SH4toStellarium.exe program. I am using it for SH3 on a vista 64 rig. When I use the program it takes my savegame data and converts it to the startup.sts script, but inside the file the Lat/Long are reversed.

This is how it wright the script.

date utc 1939/08/07T20:47:00
moveto lon 63.242973
moveto lat 3.668400
script action end

Now the lon number is actually the lat number. To get Stellarium to plot me at right spot I have to reverse the numbers or change the the second line to lat and the third line to lon. I want to use this program because I have downloaded python but have not been able to get it to work properly. Still working on this. Is there something I can change so I do not have to cheat and see my position by opening the startup script.

Pisces

01-11-09, 12:11 PM

Same here.

Aside from that, I noticed http://www.stellarium.org/wiki/index.php/Scriptson the Stellarium Wiki Scripts-page that the latest version (v 0.10.0) doesn't have a scripting engine (anymore). Version 0.10.1 should have a better script engine once it is released. I have 0.10.0 installed and starting Stellarium up by the start-up file doesn't work. The program starts, does some initialisation but then kicks back to desktop. So I guess we are forced to use an older version for the time being.

Older Windows versions:

http://sourceforge.net/project/showfiles.php?group_id=48857&package_id=52047

@ 6SJ7GT Also note on that Scripts Wikipage there have been changes in the date/time format used for versions since 0.9.x.

Note for version 0.9.x

Scripts written for versions previous to 0.9.x of Stellarium might date date command with the argument is a format like this:
date utc 2008:4:24T12:00:00
date local 2008:4:24T12:00:00

This will cause a problem in version 0.9.x - you need to update such scripts so that the date command they look like this:
date utc 2008-04-24T12:00:00
date local 2008-04-24T12:00:00

6SJ7GT

01-16-09, 08:26 PM

Just saw this and had my son help me correct the program. Try it now.

Sh4ToStellarium (http://files.filefront.com/sh4tostellarium7z/;12997374;/fileinfo.html).

Thanks for the info on Stellarium, Pisces. The date is raw input so it will actually take whatever date separator you use. I saw the update to version 0.10 but haven't tried it yet.

If there are any other problems let me know and I'll see what I can do.

Stay safe over there, panzerschutze12ss.
Mike

jmr

06-14-09, 10:35 PM

6SJ17GT, are your files still available somewhere?

Is anyone having trouble using the latest version of Stellarium (0.10.2) for navigating with SH3/4? I notice in the Stellarium\scripts\ folder the startup.sts is now startup.ssc and I'm wondering if this is why Stellarium refuses to start when I launch my SH4toStellarium.py.

Pisces

06-15-09, 11:22 AM

Probably, Stellarium got a different scripting engine with version 0.10.something, iirc. Or the old one was ripped out but the new one isn't ready yet. I did read in the latest manual of Stellarium that it can be started with the required commandline options directly:

See table, PDF page 27:
http://ovh.dl.sourceforge.net/sourceforge/stellarium/stellarium_user_guide-0.10.2-1.pdf

Perhaps someone can make a small program similar to SH4toStellarium.exe that retrieves the neccesary data from the savegame files and runs Stellarium with those --longitude --latitude --sky-date --sky-time parameters. Prefferably for both Sh3 and Sh4. Next month I should have more time to give it a shot

6SJ7GT

06-16-09, 05:56 PM

I see this got resurrected.

Just checked Filefront and I see my files disappeared, I'll get them up soon and post an update. It pays to keep backups on the hard drive.

Mike 6sj7gt

6SJ7GT

06-16-09, 06:05 PM

Files are up.
http://hosted.filefront.com/6sj7gt/

I'll work on getting something working with Stellarium10.

Mike 6sj7gt

Uber Gruber

09-28-09, 12:25 PM

Does this all work with SH3 too ? I'm looking to again attempt manual navigation with SH3.

Cheers, Ug.

don1reed

09-28-09, 03:15 PM

Yes, it does.
:up:

SteamWake

09-28-09, 03:47 PM

Glad to see I'm not alone!

Guess who just purchased a cheap plastic training sextant... :lol:

Hey dont knock them, I used one to win a few sailboat races ;) That was back in the day before reliable GPS. They were short races only a day or two and the plastic was good enough and pretty damn accurate. I did some shots and noon sights with each and they were within a few arc minutes/seconds of one another. I did miss the optics of the real thing though.

I was scared to death to take a 'real' sextant on board if it was lost or broken I would never forgive myself.

Besides if we got really lost just head west youll hit florida sooner or later :haha:

On the original topic this looks like fascinating work and Im a gonna look into it. I'm a bit afraid of having some predispositions as to 'how it should be' but Ill keep an open mind.

Very nice work guys !

ps; Stellarium is awsome

lm17

10-28-09, 01:03 PM

Hi all,

Just to inform you that the links are not working...

Regards,

L

Pisces

10-28-09, 01:26 PM

There are worksheets in in the back of the almanacs which you can find at the link he gave in a few posts back. But yeah, without a readme or tutorial it's pretty hard to grasp the technique.

Did you pm 6SJ7GT about reuploading?

Werewolf

10-28-09, 07:42 PM

So....are all the thing needed for implementing this mod in the 2 files called SH4tocellestial and the almanacs or do I need more? I seem to recall that there were more needed when this was made for SHIII :hmmm:

OrangeYoshi

10-28-09, 08:45 PM

Does this also delete the use of "ctrl+left click" to center the sub position on the mouse in the nav map?

Edit: I would know if the links were up. :P

Pisces

10-29-09, 03:18 PM

You still need to download the most important thing, the Stellarium planetarium program (http://www.stellarium.org/). The small sh4tostellarium program (on the filefront page) takes your location from a savegame, and sets up a config file for Stellarium for the right observation location. In Stellarium you measure the celestial object heights (altitudes) above the local horizon. Then with those numbers you must do some numbercrunching with the tables and worksheets in the back of the almanac. Then you can plot the results on the map. There is nothing that needs to be changed to Sh3/4 files. Except if you do want to hide the sub icon. But that is not required. Also no camera tweaks or interface modifications. Ctrl-click also works if you need it.

Werewolf

10-30-09, 03:27 AM

@picses

Okay, thank you very much for your reply :up:

berobispo

11-23-09, 01:03 PM

thanks you all for developing this method! but two questions remain:

1) mike's tutorial is no longer available and although I'm a navigation fan, I'm rather a bloody beginner and no chance for me to do star sights without a tutorial

2) when using SH3, what time to I enter (when using don1reed's python script)? SH3 shows two times, "base/GMT" and "local time".

Thanks!

btw: Stellarium 0.9.0 is the version which works for me for 0.10.x doesn't support sts scripts and v0.9.1 crashes at start.

don1reed

11-23-09, 01:13 PM

Howdy, berobispo.

Always use GMT for navigation. Its the time system all the modern almanacs are setup for.

Cheers,

berobispo

11-23-09, 01:42 PM

thanks for the quick answer!

but: is the question finally solved if SH3 gives me the real GMT? Or is it not that important when doing star sights?

and: any simple to grasp tutorial on this topic?

thx!

Dutch

11-23-09, 04:36 PM

Holy Cow........Fantastic work gentlemen! Would be nice to see if SHV will be a bit more modifiable in this department but out standing work as it stands here.

berobispo

11-24-09, 03:39 PM

about GMT: I made some custom missions and (I think:03:)found out:

-normal time (time shown without mouseover) is GMT, mouseover time is sh3 timezone time. they start at 7°30' from 0° and are 15° wide. gmt and local time don't change when saving/reloading.

-when going west, the game simulates the earth's rotation pretty well, I could pinpoint my location to about 15nm just by using the charts for sunrise/sunset provided by vanjast. given the fact that i can't measure seconds and the sun's upper limb is not always easy to discriminate I find this quite good

-when going east on the other hand, things are different. I was as far as 25°E and my local sunrise occured 25 min earlier then it was supposed to at 0°:cry: <-- should have been 1h40min if I'm not mistaken. --> it is completly unfeasible to use the ingame sun to determine local apparent noon when going east

I ended up with the following plan for real navigation (one reason: current career in the med):

save a game at approxiomately local noon, run don1reed's python script and enter a gmt time that I reason to be before my local noon, go to stellarium and do a noon sight. this works :up: a little bit of cheating because stellarium has a fixed position and the time entered doesn't change my position etc., but IMHO the best way to go. maybe I'll even try 3 star fixes, but no idea how. maybe using nautictools.de, altough I'd rather like to at least try to do the numbercrunching on my own...

Pisces

11-25-09, 02:42 PM

I uploaded all the neccesary files I could think of. My harddrive is a mess.

Bunch of files with the tutorial, almost everything you need:
http://www.filefront.com/14996485/Celestial-Navigation-for-H4.7z/

Almanacs for both SH4 and SH3:
http://www.filefront.com/14996507/1939-1945-Almanacs.7z/

Updated sh4tostellarium program: reads savegame to create stellarium config file (but I think Stellarium doesn't work anymore with the config/script-file system that Mike made it for since some version.. maybe you can find an old version of Stellarium somewhere... or be a daredevil and code a new program that makes it work)
http://www.filefront.com/14996519/sh4tostellarium.7z/

Navcharts for SH4 (if you don't want to clutter the game map):
http://www.filefront.com/14996653/SH4-Nav-Charts.7z/

Leech them while they are there. It's on Filefront, so there is no garuantee how long.

I'm goin' down

11-25-09, 11:09 PM

I do not know the first thing about navigation. If the links are repaired I will take a crack at it.

Pisces

11-26-09, 04:45 PM

Well, those links are the same files that 6SJ7GT posted. You can check inside the archives and notice the dates are all from that timeframe. I never touched them.

6SJ7GT

11-27-09, 06:22 PM

Thanks for uploading a copy of my files, Pisces. I have put them in my filefront area at:

http://www.filefront.com/user/6sj7gt

I added the 1939 - 1941 almanacs to the master file. At the moment Stellarium 9.1 seems to be easier to use. When I figure out how to get the location into the newest Stellarium I'll upload a program for that, (latitude and longitude command line options don't seem to work).

Mike 6SJ7GT

I'm goin' down

11-27-09, 07:01 PM

I am go to require some serious sit down time with this program. I am lacking is fundamentals, which might be math related, but I am not sure yet.

Pisces

11-28-09, 07:32 AM

I am go to require some serious sit down time with this program. I am lacking is fundamentals, which might be math related, but I am not sure yet.Nahh, looks worse than it is. Just a matter of adding and subtracting and looking into tables if you want to do it the hard way. Use the online almanac if you like to keep it simple:

http://aa.usno.navy.mil/data/docs/celnavtable.php

CNA0

11-30-09, 02:27 PM

At the moment Stellarium 9.1 seems to be easier to use. When I figure out how to get the location into the newest Stellarium I'll upload a program for that, (latitude and longitude command line options don't seem to work).

Mike 6SJ7GT I've installed Stellarium 0.10.2 and, actually,"startup.ssc"(with lat-long coordinates and GMT date and time introduced by "Sh4toStellarium.py") doesn't have any effect.
I've observed that Config.ini keeps "Paris" as "location" in [init_location] block.

Is it any other solution than "manual mode"?

I can't find any tool (sextant) in Stellarium to read a star altitude. How can you read it?

Pisces

11-30-09, 05:35 PM

For the 'sextant' measurement you need to press the 'z' button. Then you get the azimuth/altitude grid. Then you have to zoom in on the celestial object and 'shoot' against the nearest gridline.

I too had trouble getting Stellarium to accept a long/lat position through commandline parameters and config file. But the manual explains not everything works completely yet.

Maybe it's possible to add a 'city' location to the list with the sub's coordinates. And have Stellarium remember that as default location instead of Paris.

Unfortunately the older version (0.9 something) doesn't work with vista. Or my system anyway. :(

6SJ7GT

11-30-09, 09:18 PM

Cnao,

I just got stelarium 10 working. there is a file "Sh4tostellarium10.py in my Filefront page (http://www.filefront.com/user/6sj7gt). Try that one and let me know if it works for you.

a couple of other things to do, is set the altitude default to 0 meters and the time_zone to gmt in the stellarium config file. This doesn't seem to affect the azimuth angles for the stars though.

Pisces, if you click on a star the information on altitude/azimuth is in the upper right corner. If the clock is ticking the numbers change fast enough that getting the altitude/time right on gives a small margin of error.

Mike 6sj7gt

I'm goin' down

11-30-09, 11:05 PM

Why?

Pisces

12-01-09, 01:44 PM

Pisces, if you click on a star the information on altitude/azimuth is in the upper right corner. If the clock is ticking the numbers change fast enough that getting the altitude/time right on gives a small margin of error.

Mike 6sj7gtYeah, but this is hardcore navigation, right? ;) We got to create some means of measurement error in this method. The deck isn't even moving. Besides, I'm sure Don1reed never saw digital numbers rollover in his eyepiece. :arrgh!:

don1reed

12-01-09, 02:10 PM

lol.
I still use Stellarium 9.1 and pressing the "6" key is just like speaking "mark" to my assistant to my mind...and of course I let errors creep in by using time that is 'seconds' off the mark.

I continue to wish for an observation scope designed so that it could/would pull secondary duty as a sextant; only if one of the digital guru's out there could add decimal degrees to the elevation. sigh.

Pisces

12-01-09, 03:59 PM

why do we want to use celestial navagation?

Why?

I'll answer with the quote that I use as email signature:

Ideals are like stars; you will not succeed in touching them with your
hands, but like the seafaring man on the desert of waters, you
choose them as your guides, and following them, you reach your
destiny.
- Carl Schurz

:yeah:

I'm goin' down

12-01-09, 04:36 PM

6SJ7GT

12-01-09, 05:03 PM

Pisces

12-01-09, 05:18 PM

Sorry, I was just teasing a bit.

Perhaps Don1reed is a better person to answer that. Since I have no real experience. But to my knowledge, yes, determining where you are is it's sole purpous. We are lucky enough to have GPS to tell us where we are these days. That wasn't available 50 years back. During WW2 there was also kinds of radio navigation (radio transmitters send out radiowaves with which you could orientate yourself) But that requires significant equipment, for the navigator as wel as landbased. Besides celestial navigation was also done well before the electronic age. For celestial navigation you can make do with much simpler equipment: Something to measure positions of the celestial objects (sun, moon, planets, stars) like a sextant/octant, clock, ephemeris (tables with sun/moon/planet/star positions) or thesedays a handheld computer, pen paper and drawing tools. (if you ignore the need for observatories to make those tables in the firstplace ;) ) The earth rotates at an increadible steady pace, and the planets and moon go on their way minding their own business. Which makes it possible to predict the rising and setting and all other positions of the stars and moon/sun/planets in the sky centuries in advance. From that you can calculate back where you were when you observed those planets, sun, moon or stars.

The stars, planets, sun or moon can only tell you where you are. They cannot tell you where you should go. (Not even an astro-loger (http://en.wikipedia.org/wiki/Astrologer) can make them tell what you should do in your life. But if you are openminded it can tell you what is probable to happen :up: ... but I'm drifting off in a soapbox now ) That's your own choice. If you find out that you are not where you are supposed to be on this world, then you can take hold of the rudder/helm, take note of your compass and change course as you see fit.

Though it's usually fair weather wherever you can see the stars. :ahoy:

vanjast

12-05-09, 02:03 PM

Not sure whether this has been mentioned...
The best condensed info on navigational maths that I've found on the net - It'll give you a better understanding of methods involved with Celestial Navigation.

http://www.vanjast.com/SH4NavMod/LongitudeMath.pdf

:D

6SJ7GT

12-14-09, 07:08 PM

To All,
I revised the Tutorial to work with Stellarium 10.2 and later. They changed the scripting language. If there are any problems getting this to work contact me. You can get it on my FileFront Page

http://www.filefront.com/user/6sj7gt

NOTE; The tutorial can be run just by installing Stellarium if you want to see what's involved in celnav. Stellarium is worth installing on its own if you have any interest in astronomy.

Mike 6SJ7GT

I'm goin' down

12-19-09, 12:45 AM

In one of the downloads there is a link to A Short Guide to Celestial Navigation, http://www.celnav.de/ (http://www.celnav.de/), which appears to be basic. To me it is somewhat complicated, but it may the best one available. If their are others similar, let me know.

All I know about navigation are the basic about reading a topograhpical map and compass basics.

vanjast

12-19-09, 02:45 AM

I leave map contacts on. I am not sure what use celestial navigaton serves to assist me in the game. I am looking for a basic explanation of its purpose other than to tell you where you are? Can it tell you where you want to go, intercept information, etc. ? How does it compare to the game features that allow you to plot course? Remember, I all know is that there are star at night, and I can recognize the Big Dipper and Orion. I should have articulated my issues more clearly, and express my regrets in that regard.

The Navigation thing is an adaptation attempt for the game which hasn't really made allowances for it.

With star 'shooting' and Zenith timing, you can get your location down to single figure Nms(Kms), if not less. This really helps in the open seas far away from land.

The game 'give-aways' are :-
1) Control + Left mouse click.. which centres the map screen on your sub
2) The Captains log reports exact ship sinking locations.
3) Map zooming and attack map gives away your location.
4) Sun icon, and plotted course.

One can get rid of most of these items in the game.

There are other ways to navigate which can be used in addition to 'star gazing' , such as keeping a record of your course, speed and time - The map is fairly accurate in this regard, and it works best with the imperial measuring system (Feet, Yards, Nautical Miles, Knots).

No.. it's not perfect and it's up to you to make the game interesting from a Navigators point of view. It's also very educational and soon you'll be tossing your GPS gadget out the window...:yeah:

berobispo

12-19-09, 08:32 AM

I'm using celestial navigation (using Vanjast's "No sub on map" part of his mod) by noon sight and 3 star fixes. Most of the time without doing the sight reduction by myself. I use the php program found here:

http://aa.usno.navy.mil/data/docs/celnavtable.php

to do the number crunching for sight reductions. Mainly because it takes me half an hour to do it myself and I actually grounded my boat once while doing so :DL.

I like the uncertainty involved and the thrill of intercepting a radio contact from a dead reckoned position.

btw: Does anyone know how I can change my avatar back to Popeye?

I'm goin' down

12-19-09, 07:54 PM

send your avator to neal stevens. He can insert it.

Pisces

06-26-10, 03:37 PM

The US Naval Observatory moved their site. So if you want to use the webbased almanac use this link in the future.

http://www.usno.navy.mil/USNO/astronomical-applications/data-services/cel-nav-data

6SJ7GT

08-17-10, 04:45 PM

Thanks Pisces

I haven't looked at that site for a while.

6sj7gt

I'm goin' down

08-20-10, 07:27 PM

I have downloaded the tutorial. It speaks about opening a training mission. I did that. I cannot find the files to link to stellarium nor the file to insert the start range and longitude readings. So, I cannot get started. I am new to celestial navigation and need to get off the ground. Help is appreciated.

I made a change to the startup.sts file in the stellarium files per the tutorial. However, when I open the program to practice, the date is still 2010. I changed the date manually to match the nav. tutorial in SH4, but I am not going to figure out how to make a degree signs as i do not have that key on my keyboard, and if I have to do it manually every time, it will become a hardship. I thought the stellarium program would pick up the date and the coordinates from the nav mission. If there is another file in windows vista I have to change, such as the link from Documents and Settings, I do not know where to find it. I need basic instructions. I do not see a file labelled documents and settings.

Diopos

08-21-10, 12:46 AM

For a "degree" sign such as 87° try this: press <Alt> and without releasing it type 0176 on the number pad and then release <Alt>.

Hope it works for your system.

.

I'm goin' down

08-21-10, 01:09 AM

thanks. I still need help tying stellarium to SH4 training mission. I installed stellarium. Man, that is an amazing program. And I thought the mega mods were good!

Diopos

08-21-10, 01:42 AM

:up:

(BTW it's DiOpos not DiPpos)

.

CaptainMattJ.

08-21-10, 02:00 AM

Pisces

08-21-10, 06:15 AM

i dont get what erxactly this mod does.....? Are you talking about navigating with the stars only? if so, then you should be able to see your sub like you normally would at night, and at day you cant see where you are. thats how they did it back then. all they had was the stars to navigate, and stars can only be seen at night. therefore, it should be a simple (maybe?) mod in the folders. when its take sub marker off map. at night put it back on.This mod (actually, it is not in any way a mod-ification, as nothing in the game itself gets changed) gives you an external way to (accurately) simulate measuring the height of celestial objects. The sextant mods sofar made for SH3 and SH4 are just to crude to be usefull. With those measurements you can calculate where you are in the world.

Which star can you also see during the day? Does it not rise and set?

But seriously now, you should also be able to use the planets and moon as targets to take fixes from. If the almanac or ephemerides contains their positions. It's just easier to use the stars as they do not move on their own. Well, not measurable for this purpose anyway. Planets, sun and moon move a little bit every day, so you'd have to recalculate (extrapolate) their position in the heaven every new sighting you do.

The game stores the location of the sub in the savegame (in name_of_savegame.map). The python script reads this location and converts it to a latitude and longitude coordinate for Stellarium. The python script asks for a time and date (as I don't think it is stored in that file, though it must be hidden somewhere I'm sure, but nobody found it) and should generate a Stellarium startup script for it. Actually, to make it work you do not need to enter the time and date of the game. Your current time and date also works, it's just not immersive as you'll see a different sky. In Stellarium you measure the altitude (height) of 3 or more celestial object in question and afterwards you do the numbercrunching (mostly using tables) to develop your position plot. The celestial object positions are in the almanacs that 6SJ7GT generated for those years, or you can use the link I provided some time ago (my last message above) to the new USNO online almanac.

You'll have to keep track of your own movement inbetween skyfixes yourself through the use of deadreckoning. Meaning, plotting your movement on the map based on your speed and course. Whether or not the sub symbol is shown on the map is optional. I don't even think you can switch it on/off at the change of redlight (sunset and sunrise)

I'm goin' down

08-21-10, 01:02 PM

I need a walk through to get set up. Here is where I get lost.

I have installed SH4; and
Opened the Stellarium file on the C drive;
Inserted the file changes to Stellarium directed by the tutorial; and
Started a mission in Sub School (the navigation mission)

When I opened Stellarium the dates are the current date. What file do I open in SH4 (or Stellarium) to insert the the correct dates, longitude and latitude, etc. soo I end up at the right location, date (1943) in the Navigation mission, and, I assume, in Stellarium so when Stellarium is running, it is not opening on the current date? If I have to insert the 1943 date in Stellarium, are you advising that every time I use the program I will have to reenter the date for the 1943 date, or can I save it somehow?

Once the above is corrected, what other downloads will I use on the first tutorial. Stellarium, the Stellarium pdf., and the SH4 tutorial pdf. are the only things I have download so far. I didn't want to download the other items right off the bat, as I did not know when and if I would need them.

Pisces

08-21-10, 02:28 PM

I'm goin' down

08-21-10, 04:13 PM

I have the most recent pdf downloaded.
Here is what is says re installing, followed by my questions.

We will use the Navigation Mission in Submarine School for this introductory exercise. Start it up and look at
the map, you will see:
Starting Position:
Lat (L) 5o14’N Long (λ) 162o57’E Time 11:00 (21:00GMT)
End Point (Gold Star, Nav Mission Goal)
L 6o24’N λ162o59’E
You will need to install the freeware planetarium program Stellarium. http://www.stellarium.org/
After installing start the program so it creates a config.ini file. There should be a link to this in the Stellarium
startup directory, if not you can find it under C:\Documents and Settings\***Your login name***\Stellarium.
Open this file and find the [localization] section. Change time_zone to =utc
There is a directory called Scripts under the Stellarium program directory. there should be a file called
“startup.sts”
Paste the below lines into the file:
date utc 1943/01/01T21:02:00
moveto lon 162.960510583
moveto lat 5.23516041667
script action end
This is the information the python script gathers from the SaveData.map file and puts into Stellarium. There is
no modification of the game with this technique.

I cannot find the follwing:
After installing start the program so it creates a config.ini file. There should be a link to this in the Stellarium startup directory, if not you can find it under C:\Documents and Settings\***Your login name***\Stellarium.

I have no idea where the Stellarium startup directory is located. I cannot find a file called Documents and Settings in my C drive. I had all hidden files showing when I search for it..

Pisces

08-21-10, 04:39 PM

tomoose

08-21-10, 06:13 PM

I've been reading the posts here about celestial navigation and as a complete novice at that art I was curious about how accurate the game would be (i.e. are the stars where they are supposed to be, when they're supposed to be).
I was on patrol off Formosa on 14 June 1943 and headed due South. I noted the time (0010hr, in-game) and took a screen shot (on the left below) of what stars I could see due South.
I then used Stellarium and placed my start point as Taipei, Taiwan (aka: Formosa back in the day) and trying to correct for the time discrepancy in-game I sought to duplicate the time/date from the game (i.e. Taipei is 8 hours ahead of GMT ergo I used 14 June 1943 at 0810hr). Below on the right is the Stellarium screenshot.
It's hard to see the stars in the SH4 shot due to the size restriction of the graphic and the fact that the starfields in SH4 are not as bright and as obvious as Stellarium (is there a modded brighter starfield out there,LOL?). If you look close you'll see the similarity of the constellations (I numbered some of them for clarity).
Result? Pretty damn close allowing for the fact that my sub isn't parked in Taipei harbour etc, LOL. Again, I say this as an easily impressed novice, LOL and perhaps one of the experts will correct me if I'm out to lunch here. Having said all that I'll have to find an online tutorial and figure out how this works!!!!
http://img.photobucket.com/albums/v66/Tomaz99/SHIV/StarsinSH4andStellarium.jpg

EDIT: I just noticed that Stellarium shows 13 June vice 14 June but I'm assuming that the stars would still be in the same general location 24hrs earlier or later so I believe I can retain my "wow, cool" sensation!?!?! yes? no? LOL

I'm goin' down

08-21-10, 06:20 PM

I get an old pogo stick. When I get high enough, I check the sky. When I return to the driveway, I run inside and compare what i have seen to Stellarium. I saw Vega. What this? Jody Foster was walking on the beach?
(Why is that van outside bearing the emblem of Happy Dale Sanitorium?)

I'm goin' down

08-21-10, 06:32 PM

Then you probably have Windows Vista or Windows 7. The user profiles are stored in the folder "Users" instead of "Documents and Settings".

You should find it in: C:\Users\_Username_\AppData\Roaming\Stellarium

Okay. I found the file. The localization file was preset to the correct entry, so there was nothing to adjust. I already changed the Stellarium program directory and instructed. Now what. When I open Stellarium, it still shows my location at home where I set it the program to run and uses the current date. What do I do now? Insert the date, time, long and latitude for the practice mission? Are SH4 and the program linked? Or is the sky in SH4 real time (1940 and 1945 and you use Stellarium to figure out where your are and how to plot where you want to go, and then return to SH4 and plot it? I do not have an overview of what is supposed to be done.

tomoose

08-22-10, 08:17 AM

Pisces

08-22-10, 08:31 AM

Okay. I found the file. The localization file was preset to the correct entry, so there was nothing to adjust. I already changed the Stellarium program directory and instructed. Now what. When I open Stellarium, it still shows my location at home where I set it the program to run and uses the current date. What do I do now? Insert the date, time, long and latitude for the practice mission? Are SH4 and the program linked? Or is the sky in SH4 real time (1940 and 1945 and you use Stellarium to figure out where your are and how to plot where you want to go, and then return to SH4 and plot it? I do not have an overview of what is supposed to be done.I suspect you followed the steps shown on page 1 of the pdf document? Well, the way I read it it is just a description of how you would adjust the location in the file by hand. This isn't really the way to go every time you want to do a starfix. Instead, start with the descriptions on page 5. You need the python programming environment and adjust some lines in the python-script that 6SJ7GT wrote. (every time you go on a new patrol because the savegame folder path changes) Then you can run that every time you need to do starfixes. It wil ask time and date of the save game and it starts Stellarium automatically, and should be with the right location and time.

Pisces

08-22-10, 08:34 AM

Has anyone done any research into improving the "look" of the in-game night sky (i.e. the stars/constellations) in order to aid in celestial navigation? I'm not talking adding more stars but making the key stars more obvious. Is there a dat file or something whereby you can increase brightness et al? Just curious.I remember someone here (in one of the celnav related threads) wrote way back that the stars are only pixels plotted on a rather small sphere around you. Not proper lightsources that are drawn at infinity. So that would imply you'd even experience some parallax error in your directions if you used them ingame.

Munchausen

08-22-10, 12:18 PM

:hmmm: There was also an old attempt at "improving" the look/brightness of the stars. IIRC, they came out diamond shaped when enlarged.

I'm goin' down

08-22-10, 03:45 PM

I have download python 3.1 and the extension from page five of the instructions. I saved a mission (the Navigation Mission). Now what? What file do i open? I do not see a file that I can access called SH4toStellarium.py.

These activation instructions are not a model of clarity. They might have been placed on page one, and lead you through this process step by step. I was totally lost on page 2, so I never read to page 5, plus the pages are not numbered. Whoever put this together, might have considered he was drafting instructions for individuals who not only might not understand how to use the programs, but also are short on programming skills. Now that I have it off my chest, what do I do now?

don1reed

08-22-10, 03:53 PM

The best way to learn the navigational stars is to first learn to recognize the shape of the constellations wherein they reside (Zodiac names).

If you have a clear sky from your own back yard tonight, have a go at it. After a bit it will become routine. There are countless books, magazines, star charts available both hard copies and online to get you started.

At sea, wx, fog, haze, rain, industrial smog, and clouds will block them from your view when you need them the most. The only exception is the sun which when sitting behind a cloud will present itself as a fuzzy cotton ball sometimes. And, even then it is usable if you use the center of mass as your target and use the center of the sun for your calculations rather than upper or lower limb.

I'm goin' down

08-22-10, 04:41 PM

I will hit the deck and gaze upon the universe. Then I will run inside, start a game. But I cannot get the program to load, as I cannot decipher the instructions.

don1reed

08-22-10, 07:09 PM

Are you using Windows7?

I'm goin' down

08-22-10, 07:41 PM

Windows Version 6, Windows Vista Ultimate Operating System. (I typed winver in the command line, as Windows directed. That is what it showed I have installed.)

don1reed

08-22-10, 07:56 PM

Check your PM

I'm goin' down

08-22-10, 11:00 PM

It is the eve of the battle. Map contacts are off. I am going to use the stars to Navigate, if I can load the damn program? While the world is wondering where TF39 (Halsy's) is, I am wondering where Don Reed's email with his instructions on how to load celnav is?

Pisces

08-22-10, 11:30 PM

I'm goin' down

08-22-10, 11:57 PM

I looked in the SH4 Saved Games file and nothing was there. The instructions at the beginning of the thread have not helped.

Pisces

08-23-10, 06:35 AM

I looked in the SH4 Saved Games file and nothing was there. The instructions at the beginning of the thread have not helped.You are right a bit. The first message does not explain that you can (should) download Celestial_Navigation_for_SH4.7z from his Filefront page. It contains the tutorial and python script file among other things, except some files in it are now a bit outdated. The correct version of the python file and the latest pdf tutorial can be downloaded seperately from the filefront page. It doesn't really matter where you place that python-script for SH4. Just as long as you can reach it easily to modify or execute. What to do with it starts on page 5 of the tutorial : Tutorial on SH4 Celestial Navigation - Stellarium 10.2.pdf

don1reed

08-23-10, 11:38 AM

Sorry for the delay (speaking to last post) IGD. I don't get around here much anymore. There's a lot of nuance with the programs that I'm going to talk you through...thats the reason for PM's and email...as mentioned...I don't want to clutter up this thread. If there were a great calling for "How to", then maybe it'd be worth the time/effort to put something together. As it is, there are too many different systems playing SH3/SH4/SH5.

Let the "caveat emptor" (buyer beware) this setup may not work on all systems.

It's been my experience that getting this up and running may take a lot of patience...so kick back, grab a beer, smoke 'em if you've got 'em.

see you on email.

Cheers all,

don1reed

08-23-10, 12:04 PM

My last post to IGD may have sounded cryptic...

...but...The PYTHON program is the MOST important part of this Cel Nav op. by this method.

IN ORDER OF IMPORTANCE:

1) Getting it working on your cpu is primary.

2) Putting it (the SCRIPT) into the proper Subdirectory with annexes.

3) Making sure there are NO spelling errors in the script program.

4) Making sure ALL DATES and TIMES are in UTM/GMT format.

5) Making sure that Stellarium is in UTM/GMT format.

I'm goin' down

08-23-10, 12:07 PM

I looked in the SH4 Saved Games file and nothing was there. The instructions at the beginning of the thread have not helped.

You are right a bit. The first message does not explain that you can (should) download Celestial_Navigation_for_SH4.7z from his Filefront page. It contains the tutorial and python script file among other things, except some files in it are now a bit outdated. The correct version of the python file and the latest pdf tutorial can be downloaded seperately from the filefront page. It doesn't really matter where you place that python-script for SH4. Just as long as you can reach it easily to modify or execute. What to do with it starts on page 5 of the tutorial : Tutorial on SH4 Celestial Navigation - Stellarium 10.2.pdf

Sh4toStellarium10-ssc.py opens but cannot be read. It is either unsupported or their is a download error message.

don1reed

08-23-10, 12:11 PM

IGD:

Copy your script from the tools\script directory and paste it here.

Lets take a look at it.

don1reed

08-23-10, 12:17 PM

@ IDG:

When you open PYTHON, what appears on your display? Do you get the normal windows type of toolbar across the top of it's focus window?

don1reed

08-23-10, 12:21 PM

@IGD:

Do you get a little man "runner" icon in the top toolbar? It symbolizes "Run" the script. Pressing it should take you to the tools\script directory, where you must scroll down to your SH4toStellarium script.

(Do you see now why I said patience?) and off this thread?

I'm goin' down

08-23-10, 01:00 PM

Pisces

08-23-10, 03:14 PM

I downloaded python 2.5.6. It is in my program x86 directory. What is the path to file that I am supposed to open. I cannot read any of the py files as it says either they are unsupported or corrupt. It is not the latter. This is extremely frustrating. It has go to be easier than this.Probably version 2.6.5, as 2.5.6 isn't an official release according to the website.

The difference with my installation is the default install location. Probably due to divine providence I chose not to install in Program Files. You know, Vista/Windows 7 peculiarity. Though I cannot exactly recall how I did that some months ago. I suggest you uninstall Python first and then reinstall (elsewhere).

But if Don1reed has a better idea then I don't want to mess up this conversation you have with him. It's complicated enough.

don1reed

08-23-10, 03:36 PM

Naw, either way is good, Pisces. IGD cannot at this writing get Python to run at all. Until it runs, he's sol.

I'm goin' down

08-23-10, 03:58 PM

I'm goin' down

08-23-10, 05:32 PM

This b.s. First the thread begins with instructions that are for the most part impossible to follow. The thread does not advise on what order to install the various programs, what is essential, etc. As for python, it does not direct that is should be filed in its own directory. Python downloaded fine. But there is no execution file per the screen shot don reed sent to me. Is this program worth the trouble?

Pisces

08-23-10, 05:43 PM

Pieces was correct on the version of Python. It is filed under the C directory -- in its own directory. I have no execution file, so I cannot open it. I tried a repair installation and that did nothing. I downloaded it from the link provided in this thread.Hold on! Which 'kind of Python' have you installed?

The original message has this link: http://www.activestate.com/activepython

The one that I used and is suggested in the latest tutorial is : http://www.python.org/download/releases/2.6.5/

The latest version is a couple of releases further, but 2.6.5 works for me. Your system is no doubt different so you might need some bugs fixed.

If you still use the same version and 'brand' as I have then your installation must be messed up. I certainly have 2 .exe files (python.exe and pythonw.exe) and some text documents in the rootfolder of this Python package. I can't remember if I forced the use of one of those .exe files when I double clicked on a .py file. I think it all should have gone automatically through the installer. Make sure you install the package deliberately with administrator credentials (rightclick on the installer, then "Run as Administrator").

[EDIT] p.s. I never installed the Windows extensions as suggested in the latest turorial pdf (the sourceforge link). I downloaded the windows version of the installer and that was it.

I'm goin' down

08-23-10, 06:09 PM

As noted above, I downloaded python, and did from the site you linked. I downloaded the community edition. There is no exe file.

Pisces

08-24-10, 05:53 AM

As noted above, I downloaded python, and did from the site you linked. I downloaded the community edition. There is no exe file.Well, that is the Activestate Python version then. I have just installed that one aswel, aside from the other python.org edition. I had to install it into a seperate folder as it intended to put it into the C:\Python26 folder made for the other earlier install. There doesn't seem to be anything wrong with it by default. Everything worked perfectly: I could run the editor, named IDLE, through the shortcuts in the startmenu. (which really is a .bat file that runs the python executable with the propper command line options) The installer took care of file associations, so I just had to double click on the SH4toStellarium10-ssc.py file. It worked all normally including starting up of Stellarium.

You install of it must be FUBAR-ed. Uninstall it as best you can. Maybe their site has some more thurough procedures if you can't get rid of everything. Make sure you install the version appropriate for you system and OS kind. Meaning, I have a 64bit install of Windows 7, so I downloaded that x64 .msi file (.msi is an installer package for Windows) You may need the regular x86 installer. Check that on the properties page of "Computer". Be aware that you may need to install it deliberately as an Administrator (Run As Administrator). But I think I am repeating myself now. This is the only reason I can think of why it may have malfunctioned.

don1reed

08-24-10, 06:56 AM

@IGD:

goto this subdirectory on your computer

C:\Python26\Lib\site-packages\pythonwin\

then click on Pythonwin (Green worm icon)

If it opens your Python....Create a shortcut to your desk top...

-...-

It's been such a long time since I played around with this, I had forgotten where the EXE file was hiding.....Frustrating and frustrated :(

let us know.

Cheers

don1reed

08-24-10, 07:38 AM

I was telling IGD that I also use an iMac with OS 10.4 and it has Python25 built in. Never noticed it 'til this week. :DL

I'm goin' down

08-24-10, 10:43 PM

Pisces

08-25-10, 04:43 AM

Don Reed and I got on the telephone. We found the python.exe file. We created a script file. We tried to run the scripts. It did not work, I think. Don Reed had to leave so we did not finish. I am waiting for Reed to email me to follow up. Even if all is correct, I have no idea what to do next. What do I plug into the date and time that pops up when we try to run the script. What changes/entries do I make to Stellarium?Don't worry about what to do next in regard to input of the numbers for Stellarium. Pyhton needs to work first because doing it manually just doesn't cut it. It's too laboriously to compute the coordinates every time manually. And defeats the purpose of the celestial navigation attempt. Since you allready get to see and write your coordinates before you even make one starfix.

Good to hear Don Reed helped on the phone. I'm in the Netherlands so that wouldn't be much help. I guess it's just a matter of patience before you two can get in contact again and attempt to fix it. I know you feel like getting impatient. Whether the time spend was worth it in the end is something only you can say, afterwards. Celestial navigation is a hardcore technique, so dificulties are to be expected. But this software error should only be temporary.

don1reed

08-25-10, 06:49 AM

'Morning all. Soon as I get the better half off and running--get a slug of java into my bilges, I'll be ready to have another go at it. It's Ante Meridian here at N39 x W90.

Admittedly, instructions presented via this medium can be confusing and easily misunderstood, particularly when arthritic fingers are thrown into the mix. lol. Sometimes the only way is eyeball to eyeball; but, in our case, IGD, the telephone will have to do.

I'm going to build a *.py script file for you this morning, one that I know works, only with your computer's parameters. I'll send it to you. We'll see if that doesn't make the grade.

I suspect the nuance is the fact your system is "Vista". Once we poke at it long enough, and find out what's acceptable to it...the process will be time consuming and tedious. So....

Caveat: If this doesn't work...

You may have to return to the Python.org site and get a different program, one more developed for your system.
Cheers.

don1reed

08-25-10, 05:53 PM

Great news, IGD.

I got Python and Stellarium 10.5 working Brilliantly.

Once all the pieces are put together. . .No problimo.

Later,

Don

I'm goin' down

08-25-10, 07:22 PM

I will be in heaven (in a manner of speaking) when we get it working.

Once it is working, I will need guidance on the folowing:

How do I set it up so SH4 games use Stellarium?

What is a good tutorial or lesson to get started?

When I set it for viewing from my home town, the moon (a few days ago) was in the sky, but it was below the horizon on Stellarium. Thus, I could not compare what I saw in the sky to the program, because the views were not the same. How can I fix that?

Pieces, I appreciate your morale boosting advice. But the instructions in the tutorial simply did not apply to the new version of Stellarium, plus the instructions on how to activate Python were not consumer friendly (I am being most diplomatic re Python.) Don Reed and I have spent considerable time (several hours) over the last 2 days dealing with it via email and telephone, and hopefully will finish it tomorrow since the latest road block was recently surmounted by Admiral Reed.

don1reed

08-25-10, 08:22 PM

Best advice: go to the first post of this thread and download 6SJ7GT's Tutorials and war year (1939-1945) almanacs.

Any questions you have after taking time to read that info...everybody here will gladly help you.

But...

Once we get you up and running with Python and Stellarium 10.5, You need to begin using Stellarium in an actual game, where taking simulated sextant sights will show your progress through the ocean.

I'm goin' down

08-25-10, 08:39 PM

Pisces

08-25-10, 08:53 PM

Pieces, I appreciate your morale boosting advice. But the instructions in the tutorial simply did not apply to the new version of Stellarium, plus the instructions on how to activate Python were not consumer friendly (I am being most diplomatic re Python.) Don Reed and I have spent considerable time (several hours) over the last 2 days dealing with it via email and telephone, and hopefully will finish it tomorrow since the latest road block was recently surmounted by Admiral Reed.Pieces ... :nope: (or did you say you were dyslexic, if so then I'm sorry I forgot)

I'm curious about the details of the reasons for Python not working (by itself). I wasn't aware of a new Stellarium version (past 10.2) but that's allways a possibility ofcourse. Still I gathered the problem lied in Python not working at all. Unless my earlier installation of the Python.org release solved some issues for the Active(something) version of Python that was unknown to me, I can't imagine why it went so bad for you, but so easy for me. (Yikes, awfull sentence I wrote there)

I'm goin' down

08-25-10, 09:46 PM

I'm curious about the details of the reasons for Python not working (by itself). I wasn't aware of a new Stellarium version (past 10.2) but that's allways a possibility ofcourse. Still I gathered the problem lied in Python not working at all. Unless my earlier installation of the Python.org release solved some issues for the Active(something) version of Python that was unknown to me, I can't imagine why it went so bad for you, but so easy for me. (Yikes, awfull sentence I wrote there)

I am not touching that with a ten foot pole. Don Reed can if he so chooses. What could be more productive is to issue new instruction dealing with windows vista. That would answer your questions.

don1reed

08-26-10, 06:47 AM

Herein lies the culprit. This very medium, this forum which we use to communicate; and me. Yes, me. I was content to leave well enough alone, using what worked for me, Python 2.6 and Stellarium 0.9.1. Why "upgrade" to something new? In other words, "If it ain't broke, don't fix it."

Old timer me, decided that if my system worked, it should work for IGD's rig as well....lol, not to be.

Once it was determined that IGD and I were using 2 different Stellarium pgms, I got off my duff and DL the newest version. [I] Reworked the SH4toStellarium10.ssc script for my cpu's subdirectory. And yet, all was not well, as the date/time and geo coords continued to stay in Paris with today's date/time. Default? Probably. So, I carefully read the script and discovered that it was supposed to write an sh4.ssc with the game date/time/posit into the SCRIPT directory of the new Stellarium.

My sys os is W/7 and for some reason, due to permissions authority, it was not allowing the Python script to write to Stellarium. It wouldn't let me edit any of the *.ssc files unless I physically drug them from the "My Computer" focus box to the desktop and modified them there.

Since this was preventing the "sh4.ssc" script from being written, I decided to create a blank "sh4.ssc" with Notepad, drag it into the Stellarium\Script directory, to kick-start the deal--Lo and behold, it worked. Opening the Stellarium\Script\sh4.ssc disclosed the proper params for my game.

I see now, this was just a ploy by 6ST7GT to drag me kicking and screaming into the 21st century. That was a dirty trick, Mike. :D

And that, Pisces, is how I lost all my remaining hair. (I think I'll start shaving my legs--for balance.) :haha:

don1reed

08-26-10, 08:03 AM

Here is a pic of the NLSR (Observation scope) from SH3 (It's just one I happen to have...I know this is an SH4 thread).

What I wish the Mod Guru's could accomplish is find a way to accurately measure the altitude of the LL or UL of the body to the Ocean's surface. We wouldn't need Python or Stellarium then.

To give the "O scope" a real function would be nice....dreaming....

Oh...a Split-Image would be even better, where you could rotate the body to the surface. Sweet.

http://a.imageshack.us/img827/50/observation.jpg (http://img827.imageshack.us/i/observation.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

Munchausen

08-26-10, 10:57 AM

I will give it a shot (I mean a sighting!)

:cool: Actually, "shot" is proper terminology. Navigators "shoot the stars" to get a fix.

Pisces

08-26-10, 12:09 PM

My sys os is W/7 and for some reason, due to permissions authority, it was not allowing the Python script to write to Stellarium. It wouldn't let me edit any of the *.ssc files unless I physically drug them from the "My Computer" focus box to the desktop and modified them there.Sounds like you have Stellarium inside the Program Files folder. Hmm, IGD too perhaps, then I guess there is another difference why it works easier on my end.

Microsoft chose to protect the Program Files folder with good intentions, by preventing malware from infesting it without the users notice, but man can this be a pain in the stern if you want to do things deliberately. In XP it allready has a more basic kind of protection, but since every user in it by default becomes an administrator, nobody noticed these restrictions. In Vista and 7 the first user account that is created at installation is only administrator by default. (And there is a buit-in administrator account, but disabled) All following become ordinary users, unless manually made a member of the administrators group.

@I'm Going Down

I agree the procedure could use an update. But ultimately it's only 6SJ7GT that can edit hit first message. Also, It would be important to know what went wrong on your end exactly with Python itself. I explained that I did nothing special during install (well, aside from a different folder location) but that didn't seem to help you. (assuming you actually did follow that advice at some point) You reported that you couldn't find any executable with which you could run it (python.exe). Did you eventually find it? And were you eventually able to get the programming environment to start itself(there should have been a IDLE.bat somewhere to run it; without using any kind of SH4toStellarium script or Stellarium config file for the moment) Sofar we only know that Don1Reed fixed, ... updated his Stellarium. ... And shaved his legs. ;) But what steps you took I did not get enough feedback on. And you were the one having the problems.

don1reed

08-26-10, 01:24 PM

I'm an iMac user, Pisces, and I only purchased the pc for running SH. The pc is a lot more tedious...and frustrating sometimes. :wah: (The cat is out of the bag)

No blood, no foul. :DL

Pisces

08-26-10, 02:29 PM

I'm an iMac user, Pisces, and I only purchased the pc for running SH. The pc is a lot more tedious...and frustrating sometimes. :wah: (The cat is out of the bag)

No blood, no foul. :DLWhoopsy, I forgot.

I'm goin' down

08-26-10, 02:46 PM

Sounds like you have Stellarium inside the Program Files folder. Hmm, IGD too perhaps, then I guess there is another difference why it works easier on my end.

Wrong, Stellarium is in its own directory in the C file. C:\Stellarium.

As for me explaining what went wrong, I am not going to do it. I do not understand the final adjustments that don reed made this morning. I lack the technical qualifications to fully comprehend what he did/changed.

I'm goin' down

08-26-10, 03:12 PM

Here is a something similar to my recent email to Don Reed. Mr. Reed can probably resolve Question No. 1, which he is familiar with.

I am on a single mission off of the Solomen's. The date is 11/14/1943. base time is 0648hrs. I save the mission and exit SH4. I input that information to python. When I run python, Stellarium opens.

Question No. 1. Stellarium says I am in the Pacific Ocean, so I assume I am at the correct location. On Stellarium's world map, the arrow it set and points to the Pacific Ocean, so that confirms my assumption. Next, I open the configuration window in Stellarium and run the SH4 script per your instruction. I assume that will run the most recent saved game in SH4. Unfortunately, it returns me to the Stellarium main screen where it still shows the current date (8/26/2010) and current time. What am I doing wrong?

Specific information. When I run the SH4toStellarium in python, Stellarium opens and says I am in the Pacific Ocean, so I assume I am at the correct location. Note, I had set the date in python 1943/11/01, which is the date of my saved game. However, when I open the configuration window in Stellarium and run the SH4 script per your instructions, I still get the current date instead of a date of November 14, 1943. The startup.sst folder in Stellarium does not bear a 1943 date. It still bears the following, incorrect data, which does not match the saved game,

Name: Startup Script
// Description: Script which runs automatically at startup
//
date utc 1943/01/01T11:02:00
moveto lon 162.960510583
moveto lat 5.23516041667
script action end

Second question. SH4 says base time is 0648 hrs. I am off the Solomen Islands. I am not sure what base time means. This is a single mission, and there is no indication on the map screen as to what the base is. How does base time coordinate with GMT, and if I am off the Solomens, how do I account for the time difference between that location and the base?

Third question. How do you figure the GMT for a remote location like the Solomens? This is related to question No. 2.

don1reed

08-26-10, 04:45 PM

@IGD:

1) The Startup position shown when Stellarium opens is not your correct position. Goto the Lower Left Side tool bar and click on the "Wrench"
the configuration window. Once it opens, click on "Scripts" icon. When it opens, click on sh4.ssc script and press the run button at the bottom.

If this is exactly what you're doing and getting those results, then you'll need to look at the sh4.ssc script file to see what's written there. The sh4.ssc script file is located in C:\Stellarium\scripts\ directory. Copy and paste it here so we can look at it.

The SH4toStellarium10.ssc.py script in Python is what is writing to the sh4.ssc script in Stellarium to call up the proper date/time/position of your game.

2) Base Time is the Local Time at the Naval Base your mission started from, i.e., Hawaii, that would put you in Time Zone K (-)10 hrs. or 6:48 base time = Local time on 11 NOV 43. 6:48K time = 10 Nov 43 20:48Z (GMT)

You headed West and crossed the IDL (International Date Line)(Represented by the Diagonal line across the chart below) and now in the waters off the Solomen Is.

Physically Crossing the IDL East to West you lose one day (-1) so the GMT Date would now be

10 NOV 43, Local time would be 10:48W in the vicinity of the Solomens.

As promised, here is USN's GMT chart. Copy it and make it any size your heart desires. (Click on it to see a larger pic)

The Sun travels 15° each hour, Therefore each time zone degree is in the exact middle of each time zone and has 7.5° on each side. The Navigator aboard ships is in charge of making sure all clocks (set to local time) and chronometers (are set to GMT). It's something to be concerned with as your navigation depends on it.

http://a.imageshack.us/img523/213/gmtconverterot5.th.jpg (http://img523.imageshack.us/i/gmtconverterot5.jpg/)

I'm goin' down

08-26-10, 05:53 PM

Here is my Stellariam/scrpts/sh4.ssc file content:

core.setDate("1943:11:14T06:48::00")
core.setObserverLocation(-157.981558667, 21.2394480833, 2, 0, "SH4 Navigation Point, Pacific Ocean", "earth

Here is the startup.ssc file content:

//
// Name: Startup Script
// Description: Script which runs automatically at startup
//
date utc 1943/01/01T11:02:00
moveto lon 162.960510583
moveto lat 5.23516041667
script action end

Here is the startup.sts file content:

date utc 1943/11/01T21:02::00
moveto lon 125.421066417
moveto lat 10.2463980833
script action end

don1reed

08-26-10, 08:36 PM

Here is something I need you to try:

1) Enter date/time data into Python. When it throws you automatically into Stellarium, exit the Stellarium program.

2) Enter Stellarium again via the Desktop shortcut. Execute the sh4.ssc script in the configuration focus box.

3) Let me know what happens.

4) Don't bother with the startup script, it has nothing to do with Python or SH4.

I'm goin' down

08-26-10, 11:56 PM

It worked a couple of times. Then it stopped working.

don1reed

08-27-10, 06:26 AM

I suspect that Stellarium may have gotten corrupted in the learning process. It may require an uninstall and new install. Start up your single mission in SH4, move your boat a ways (tc x512). Stop. Do a save game. Now, try the whole process again, Python plus Stellarium and see were Stellarium has you.

BUT,

If that doesn't work...

Trying the "process" using a single (training) mission is something I, personally, would not do. To give it a real test for ability to work, I suggest starting a new game/mission going into C:\Python26\Tools\Scripts\SH4toStellarium.ssc.py and changing the directory string embedded in the script:

(C:\\Users\\bill\\Documents\\SH4\\data\\cfg\\SaveG ames\\0000000?\\SaveData.Map) <--------- Nota Bene: This may not be your exact directory string--I'm doing this from memory on my Mac. The "?" means to insert the exact game number. Don't forget to save after changing the string.

Try it then.

IF However, if it still doesn't work--do the unistall....new install of Stellarium.

don1reed

08-27-10, 08:55 AM

I use the Python/Stellarium Navigation (PSN) method for both SH3 and SH4.

SH3 is Straight forward in that the saved games are placed in the CAREERS directory and the single missions are saved in the SINGLE MISSION directory.

In SH4, I don't know if Career missions are separated from Single missions. (I've never saved single missions using either sh3/4) Are they thrown into the same pot? If so, a great amount of confusion will take place when developing your Python SH4toStellarium10.ssc.py script file for SH4.

If you've chosen the incorrect "0000000?" game, Stellarium will not show any change in you geo coordinates as you progress during your cruise.

This requires RFIR (Requires Further Investigative Research)

Just finished checking my SH4. Started and saved a single mission and it's as I thought, everything saved is thrown into the same pot. the Player must be aware of which saved game he/she chooses when making changes in their SH4toStellarium20.ssc.ph script file.

@I'm Going Down:

In view of what I just discovered, I suggest you delete your current Single Mission and begin a new career and use the new "0000000?" game number in your SH4toStellarium10.ssc.py script file.

don1reed

08-27-10, 09:44 AM

Here's a quick test you can perform:

I've opened and saved a copy of my SH4 SaveData.Map file:

[Mark]
PointsNb=0

[Ruler]
PointsNb=0

[Range]
PointsNb=4
Pt0=-1171460.38,6779873.00,0.00
Pt1=-1164979.36,6980244.54,0.00
Pt2=-436945.69,6721544.00,0.00
Pt3=-795561.72,5853088.20,0.00

[Angle]
PointsNb=0

[Waypoint]
PointsNb=8
Pt0=-1217501.54,6676092.09,-2.35...<----This is my current position

[KGSelector]
PointsNb=0

A quick check to determine my REAL Geo Coordinates is to divide each of those two quantities above by 120,000, i.e.,

-1217501.54 / 120000 = -10.1458
6676092.09 / 120000 = 55.6341 or,

L55°38.0'N, λ10°08.7'W <-----This is my REAL (Lat-Long) position in the game.

So, one can easily compare the coordinates of what one obtains via Sight Reduction (PSN) and where the cpu really has you. Just Zoom in on the F5 Chart screen in the game to where you can easily see one degree Lat/Long, hold down the CNTL key while right clicking your mouse.

If you're between 5 and 10 nautical miles off, not to worry, you can see that far from the bridge (scope up). Any more than 10 nm, I'd redo the sight, check your time piece or GMT convertion, or redo your math.
If the Altitude of Diamondhead at Waikiki is 761 ft. and the height of your eye on the bridge of your sub is 20 ft., you should be able to see the top of Diamondhead when you're about 32 nm radius away. So, it all depends on what your landfall is supposed to be that determines how accurate you need to be. Do you have to find a downed pilot in a fog? Then you damned well better measure twice before cutting once.

Cheers,

don1reed

08-30-10, 09:17 AM

Good News. "I'm Going Down" tells me his Python/Stellarium combo is finally working.

His saved games, for some unknown reason, weren't being saved where they were supposed to. When we last spoke, the only place the saved games were apparently going was into ...\SH4\data\cfg...etc., but that wasn't the case; instead, he advised me, they should have been saved into the ...\TMO\date\cfg...etc., directory. At any rate, all seems to be working now.

Most times perseverance pays off, and in IGD's case it sure has. Nicely done.

Now...for the hard part. It's back to school (we're never done with it).

Always remember the 5 P's:

Prior Planning Prevents Poor Performance.

Fair winds, mate! :yeah:

Pisces

08-30-10, 09:50 AM

And cloudless nights! :up:

Seems he used that MultiSH3/4 tool to get his profiles seperate for different installs. (the TMO-folder instead of SH4) Yeah, that could be usefull to have known that. :up:

don1reed

08-30-10, 10:53 AM

Good afternoon, Pisces!

I've been meaning to ask...which process of sight reduction have you settled on? (H.O. pub 211 or something similar)

Pisces

08-30-10, 12:03 PM

I've intended to use the Ageton tables (H.O. 211) but haven't really dug into them yet. I very sporadically played SH(3) the past year. To busy with work to allow myself long-nighters. Sofar, I cheated mostly with the online almanac to do the number crunching. :oops:

Rockin Robbins

08-30-10, 01:07 PM

Thought folks might appreciate seeing some of the problem they have to deal with to make SH4 Celestial Navigation possible. I'm sure you think the sun rises in the morning and sets in the evening. A nice animation would show it ascending vertically or at a small angle up into the sky.

Except sometimes! Let's say your sub is sitting in Dutch Harbor on the morning of February 2, 1943. Let's say you had the time to sit on the bridge and watch the sun from 9:39 am until 4:51 pm. What do you think you would see?

Well, reality is different. Using a decent astronomical and solar system simulator, Cartes du Ciel, with the sky artificially turned dark in spite of the sun being up so you can see the motion of the entire sky, here is what you would encounter. First of all, the sun follows a path mostly across the sky, moving from left to right as you face south. Yes, it came from below the horizon and exits below the horizon at sunset but mostly it flies across the sky from sunrise to sunset, never reaching higher than 20º above the horizon! As a bonus for this day, our Creator tossed in a free total solar eclipse, with maximum eclipse at 1:57 pm.

I apologize for the small size of the sun, that is the size it really is. And although the moon flies formation across the sky all day with the sun, you can't see it! When the moon is that close to the sun it is a new moon and we're looking strictly at the unilluminated half, which is black. The moon only becomes "visible" during the eclipse, as a dark disk hiding the sun.

I don't even want to tell you what the sky does in Dutch Harbor when you face north at night! Enough insanity for one day.

http://i196.photobucket.com/albums/aa293/RockinRobbins13/Silent%20Hunter%204/DutchHarbor02041943.gif

don1reed

08-30-10, 01:09 PM

@Pisces:

Nothing to be embarrassed about. I often have to be in the proper mood / frame of mind myself. Relying on modern conveniences too :DL sometimes. Summer has too many distractions...definitely a winter pass time.

I find if I stay at it too long in the "game" format, I tend to get bored with the process. RL navigation has a lot more challenges and a lot more at stake which tends to keep you more focused.

RL in general, in these times, has been doing that quite on it's own, hey?

Cheers,

don1reed

08-30-10, 01:43 PM

@Rockin Robbins:

Say, that's a neat Astro/solar sys sim. :up:

However, I don't see any navigational difficulty with 53°54.6'N x 166°31.9'W (Dutch Harbor) anymore than I would with 59°32.5'N x 001°37.3'W (Fair Isle, Scotland, UK) in the Orkney-Shetland gap. I've not sailed the North Pacific, but have been in the North Sea. I can imagine it has it quirks, hey?

I'm goin' down

08-30-10, 02:51 PM

I looked at the program you use. I could not figure out the whistles and bells. Is there a tutorial on how to use it?

don1reed

10-02-10, 10:10 AM

I've been using these plotting sheets to find the one which can be used most easily with SH3 and SH4. The 4 pics at the bottom are all usable in RL; but the easiest to use in the "games" and most conforms with the F5 chart are the first two, immediately below. It requires that you use the center horizontal line as the Nearest Latitudinal parallel to your in-game position.

Latitude is obtained by drawing a line from point "A" in the lower-left corner to the nearest vertical line to the right. Now you draw short lines, one above and one below to designate the whole degrees above and below your present whole latitude. Individual minutes of latitude are obtained by placing one point of a pair of dividers at point A and the other point along the diagonal, drawn in, line.

Longitude is represented by the vertical lines placed every two minutes apart. These longitudinal lines are always equidistant. I've shown two examples here:

http://img690.imageshack.us/img690/2554/p13jon.th.jpg (http://img690.imageshack.us/i/p13jon.jpg/)

http://img375.imageshack.us/img375/3766/p11n.th.jpg (http://img375.imageshack.us/i/p11n.jpg/)

These Plotting Sheets all work and are free to copy and use.

http://img243.imageshack.us/img243/3945/smallscaleplottingsheet.th.jpg (http://img243.imageshack.us/i/smallscaleplottingsheet.jpg/)
This is for close in work near shore. Small scale.

http://img227.imageshack.us/img227/96/plottingsheet.th.jpg (http://img227.imageshack.us/i/plottingsheet.jpg/)
This is used for normal use at sea in open water.

http://img838.imageshack.us/img838/2932/longplottingsheet.th.jpg (http://img838.imageshack.us/i/longplottingsheet.jpg/)
This is the form where the longitude stays the same, but the latitude varies.

http://img541.imageshack.us/img541/3708/cgplottingsheet.th.jpg (http://img541.imageshack.us/i/cgplottingsheet.jpg/)
This form is from the US Coast Guard, dated 1941.

Cheers,

Pisces

10-02-10, 11:10 AM

Nice charts! BTW, it's Schiermonnikoog, not Schiermoonikoog. ;)

don1reed

10-02-10, 01:30 PM

LOL XD LOL

You guys just about used up the alphabet with that one. (Nice catch)

Pisces

10-02-10, 02:34 PM

Yeah, we tried an attempt at disturbing the invasion plans of Hitler by making it unpronounceable, but it didn't really work. Instead, he put bunkers on it. :damn:

TorpX

12-12-10, 08:08 PM

Can someone help me with this?
I would like to give celestial nav a try but can't get the business to work right.

I got the No boat on map mod working- ok.

I installed Stellarium 10.6.1- ok.

I installed Python 2.7.1- ???????

I have edited the SH4toStellarium.py script- ok.

However, when I start up the Stellarium program, it shows the default location and the present time. I opened up the startup.ssc file to check to make sure it is being changed, but the Stellarium program just ignores it.
I must be missing some trick here.

don1reed

12-12-10, 08:19 PM

Howdy, TorpX.

When you open Python, does it ask your for the date and time of your game?

TorpX

12-12-10, 09:10 PM

Howdy, TorpX.

When you open Python, does it ask your for the date and time of your game?

Yes, I click on the SH4toStellarium.py shortcut, it opens a window, I enter the date and time, them it closes. I think the problem must have something to do with configuring Stellarium.

Could someone who is using the 10.6.1 version of Stellarium post a copy of their startup.ssc file so I can see exactly what it is supposed to look like?

don1reed

12-12-10, 09:19 PM

I see.

Well, what should happen when you enter the date, then time, it should open stellarium automatically.

It's late here and I'm heading to bed for now. I'll be back in the a.m. and let you know what's tickin'

Don't dispair.

Later.

don1reed

12-13-10, 10:15 AM

G'Day TorpX

Lets try to fix this:

1) I use Python 2.6 and my dir looks like:
DLLs
Doc
include
Lib
libs
Scrips
tcl
Tools

2) The SH4toStellarium10-ssc script should be located in:
Python26\Tools\Scripts\ subdir. If not, put it there.

3) My SH4toStellarium10-ssc script looks like this:

# Change the directory on the next line to point to SaveData.map in your saved game directory.
savedgame = "C:\\Users\\Gamer\\My Documents\\SH4\\data\\cfg\\SaveGames\\00000006\\Sa veData.map"
# Set the Stellarium directory
stellocation = "C:\\Stellarium"

####### End Editable locations #########

# read savegame.
f=open(savedgame,'r')
content= f.read()
f.close()
# find lat & Lon in the file
start = content.find("Waypoint")
longst = content.find("Pt0=",start)
longnd = content.find(",",longst)
latnd = content.find(",",longnd+1)
# convert to dec deg
longitude = float(content[longst+4:longnd])/120000
latitude = float(content[longnd+1:latnd])/120000

# get date&time (input)
date = raw_input('GMT yyyy/mm/dd :')
time = raw_input('GMT hh:mm :')

# set the ocean label
if (-90 < longitude <= 30):
ocean = "Atlantic Ocean"
elif (30 < longitude <= 105):
ocean = "Indian Ocean"
elif (longitude <= -90 or longitude > 105):
ocean = "Pacific Ocean"

# Write startup script.
date = date.replace('/', ':')
longitude = str(longitude)
latitude = str(latitude)

stella=open(stellocation + "\\scripts\\sh4.ssc",'w')
stella.write("core.setDate(\""+date+"T"+time+":00\")\n")
stella.write("core.setObserverLocation("+longitude+", "+latitude+", 2, 0, \"SH4 Navigation Point, "+ ocean +"\", \"earth\")");
stella.close()

# now open stellarium and take your star sights
prog = "start /d \""+ stellocation +"\" stellarium.exe --startup-script sh4.ssc"
os.system(prog)
sys.exit()

4) The last paragraph in the script above tells Python to open up Stellarium.

5) Stellarium opens with whatever default info you have in the program. I use Stellarium 0.10.5. I then move my cursor to the lower left side of the screen and a pop-out menu appears. I select the "wrench and star" icon, which is the config window.

6) The Config Window opens and I select the "Scripts" icon located at the top of the focus window.

7) This opens a new focus window where I select the "sh4,ssc" script. Press the right pointing arrow at the bottom of the window.

8) It opens to the proper date and time of my game, showing all visible celestial bodies for the Lat/Long of my boat's position. Select your choice of objects (three stars for a good fix). Allow ~60° between bodies.

If you are diligent and pay close attention to detail, take a close gander at the SH4toStellarium10-ssc script. Very near the top of the script it shows that the Stellarium program is in the C:\ directory.
It says:
stellocation="C:\\Stellarium"

Make sure it's that way in your cpu too.

Let us know how it goes.

Cheers,

don1reed

12-13-10, 12:16 PM

One small caveat, TorpX. I always do a "Save" then "Continue" with SH4 or SH3, (I use this system for both games), just to update my boat's true position whenever I prepare to take a sight.

TorpX

12-14-10, 08:12 AM

I have edited the SH4toStellarium.py script to conform to what you posted. There were substantial changes.

I still can't get it to work.

There maybe multiple problems here. I tried to go by the instructions in the tutorial posted earlier in the thread, but have no idea about the Python "Windows extensions". Also, I am using Windows Vista, and the latest version of Stellarium. There maybe issues here.

Now, when I run the edited script, a window flashes on the screen and immediately closes. There is no input of date or time, Stellarium does not start, and no ssc file in Stellarium is written.

don1reed

12-14-10, 10:38 AM

Hi, TorpX.

You understand, of course, that the script I posted in Post#142 is how it appears on my cpu. We need to see how it appears in your cpu.

When you get a chance, copy your script file and paste it here so we can take a look.

Cheers,

don1reed

12-14-10, 10:47 AM

The Directory stream in the script file needs to mirror what's in your cpu--exactly.

It should be precisely as written in YOUR cpu's directory, i.e.,

...My Documents\SH4\data\cfg\SaveGames\...

The Spelling and punctuation must be precise...no extra "spaces"
or missing "\", and Proper Upper/Lower case words where written. Any tiny error input will be garbage output.

TorpX

12-15-10, 08:43 AM

Yes, I realize the paths, names, and syntax must be correct.

This is the script I used before:

import string
#read savegame. Change the directory on the next line to point to SaveData.map in your saved game directory.
f=open("C:\\Users\\Owner\\Documents\\SH4\\data\\cfg\\SaveG ames\\0000000d\\SaveData.map",'r')
content= f.read()
f.close()
#find lat & Lon in the file
start = content.find("Waypoint")
longst = content.find("Pt0=",start)
longnd = content.find(",",longst)
latnd = content.find(",",longnd+1)
print start
print longst
print longnd
print latnd
#convert to dec deg
longitude = float(content[longst+4:longnd])/120000
latitude = float(content[longnd+1:latnd])/120000
#get date&time (input)
date = raw_input('GMT yyyy/mm/dd :')
time = raw_input('GMT hh:mm :')
#Write startup script. Change the next line to suit for your Stellarium startup script.
stella=open("C:\\Games\\Stellarium\\scripts\\startup.ssc",'w')
stella.write("date utc "+date+"T"+time+":00\n")
stella.write("moveto lon "+str(longitude)+"\n")
stella.write("moveto lat "+str(latitude)+"\n")
stella.write("script action end\n")
stella.close()
#now open stellarium and take your star sights

....it wrote to startup.ssc file:

date utc 2001/01/01T23:59:00
moveto lon 120.01051
moveto lat 14.5458591667
script action end

The problem was Stellarium program did not use the values in the file. It is a new version, 10.6.1 and I have no way of knowing what the correct format and such.

I also tried another Python script based on what you posted:

#read savegame. Change the directory on the next line to point to SaveData.map in your saved game directory.
savedgame = "C:\\Users\\Owner\\Documents\\SH4\\data\\cfg\\SaveG ames\\0000000d\\SaveData.map"
# read savegame.
f=open(savedgame,'r')
content= f.read()
f.close()

#Set the Stellarium directory
stellocation = "C:\\Games\\Stellarium"

#find lat & Lon in the file
start = content.find("Waypoint")
longst = content.find("Pt0=",start)
longnd = content.find(",",longst)
latnd = content.find(",",longnd+1)
print start
print longst
print longnd
print latnd
#convert to dec deg
longitude = float(content[longst+4:longnd])/120000
latitude = float(content[longnd+1:latnd])/120000

#get date&time (input)
date = raw_input('GMT yyyy/mm/dd :')
time = raw_input('GMT hh:mm :')

# set the ocean label
if (-90 < longitude <= 30):
ocean = "Atlantic Ocean"
elif (30 < longitude <= 105):
ocean = "Indian Ocean"
elif (longitude <= -90 or longitude > 105):
ocean = "Pacific Ocean"

#Write startup script. Change the next line to suit for your Stellarium startup script.
date = date.replace('/', ':')
longitude = str(longitude)
latitude = str(latitude)
stella=open(stellocation + "\\scripts\\sh4.ssc",'w' (file://\\scripts\\sh4.ssc",'w'))
stella.write("core.setDate(\""+date+"T"+time+":00\ ")\n")
stella.write("core.setObserverLocation("+longitude +", "+latitude+", 2, 0, \"SH4 Navigation Point, "+ ocean +"\", \"earth\")");
stella.close()

#now open stellarium and take your star sights
prog = "start /d \""+ stellocation +"\" stellarium.exe --startup-script sh4.ssc"
os.system(prog)
sys.exit()

.....it doesn't request inputs for date and time, doesn't start Stellarium, and doesn't write to sh4.ssc.

I don't know what else to try at this point.

don1reed

12-15-10, 11:28 AM

Looks like we're about to get lost in the woods, TorpX. How about sending me a PM. Click on my name above my avatar. Maybe we can straighten this out via the twisted-pair(telephone). I'm retired and can make the conus call at your convenience.

Cheers,

Scottb8411

12-15-10, 11:57 AM

Hi, TorpX,

I've just started using this Celestial Navigation process as well, but I am able to run the Python script SH4toStellarium10-ssc.py to open Stellarium 10.6.1. SH4toStellarium10-ssc.py will write the sh4.ssc script in Stellarium. I should also note that I am having success with WIN XP, please advise if you are running Vista or WIN 7.

There are only two lines to edit in this script as Don mentioned. However, the script will still open and request the date and time even if your Saved Game and Stellarium paths are wrong. That leads me to believe there is an issue with your SH4toStellarium10-ssc.py script. I'll paste mine below,Please edit yours as appropiate:

# By Michael Jones, 01/01/2008. mjones004@ameritech.net
# Revised 11/29/2009 to work with Stellarium 0.10.2
# This program reads the latitude and longitude data for a
# sub in Silent Hunter III, IV and creates a startup script for
# Stellarium. This sets the Date, Time and Location of the
# sub in Stellarium, allowing players to use celestial navigation in the game.

import string, os, sys

####### Edit Locations here ############

# Change the directory on the next line to point to SaveData.map in your saved game directory.
savedgame = "E:\\My Documents\\SH4\\data\\cfg\\SaveGames\\00000000\\Sa veData.map"
# Set the Stellarium directory
stellocation = "C:\\Program Files\\Stellarium"

####### End Editable locations #########

# read savegame.
f=open(savedgame,'r')
content= f.read()
f.close()
# find lat & Lon in the file
start = content.find("Waypoint")
longst = content.find("Pt0=",start)
longnd = content.find(",",longst)
latnd = content.find(",",longnd+1)
# convert to dec deg
longitude = float(content[longst+4:longnd])/120000
latitude = float(content[longnd+1:latnd])/120000

# get date&time (input)
date = raw_input('GMT yyyy/mm/dd :')
time = raw_input('GMT hh:mm :')

# set the ocean label
if (-90 < longitude <= 30):
ocean = "Atlantic Ocean"
elif (30 < longitude <= 105):
ocean = "Indian Ocean"
elif (longitude <= -90 or longitude > 105):
ocean = "Pacific Ocean"

# Write startup script.
date = date.replace('/', ':')
longitude = str(longitude)
latitude = str(latitude)

stella=open(stellocation + "\\scripts\\sh4.ssc",'w')
stella.write("core.setDate(\""+date+"T"+time+":00\")\n")
stella.write("core.setObserverLocation("+longitude+", "+latitude+", 2, 0, \"SH4 Navigation Point, "+ ocean +"\", \"earth\")");
stella.close()

# now open stellarium and take your star sights
prog = "start /d \""+ stellocation +"\" stellarium.exe --startup-script sh4.ssc"
os.system(prog)
sys.exit()

Once you get the above working and Stellarium opens automatically, please remember to click the wrench icon and then select the Scripts tab to run the sh4.ssc script to import your Saved Game Time/Date data into Stellarium.

Hope this helps to get you started.

Now if I can figure out what timezone I'm in out in the middle of the Pacific!

TorpX

12-15-10, 06:23 PM

Hello Scottb,
I am using Vista, but I think I have it working now.

I was going through the thread to review and I downloaded the python script to look over. It turns out I was using the old version.:O: I haven't had a crack at the math end of things yet, but that part should be a little easier for me.

If you all don't hear from me in the next few days, you can assume I've run aground.:D

I'm goin' down

12-15-10, 06:36 PM

I would like to see a basic step by step tutorial, preferably a video tutorial, on how to navigate once the program is installed. I could not understand the instructions given some time ago.

I'm goin' down

12-18-10, 12:52 PM

What I intended to convey was this. I finally got the program installed with Don Reed's excellent assistance. However, after do a bunch of reading about celestial navigation, I could not follow the initial tutorial. I had no idea how to sight, and how that related to my position. I think it is something you have to do a few times, and then it sinks in. Anyway, if someone could do a break through tutorial, perhaps a video if that is feasible, I would jump in head first. Get aaronblood interested. He has the capability to do some amazing stuff.

TorpX

12-22-10, 07:08 PM

I would like to see a basic step by step tutorial, preferably a video tutorial, on how to navigate once the program is installed. I could not understand the instructions given some time ago.

I agree. The tutorial isn't very helpful. The navigation mission in my setup isn't the same as in the tutorial and I had trouble using the USNO almanac. I think it would be better to use the pdf almanacs in the thread, and possibly construct a special navigation mission for this.

Otherwise, I found The Mathematics of the Longitude by Wong Lee Nah to be very helpful. I don't understand all the methods, but I think I can use the Intercept method well enough (for game purposes anyway).

One more thing, I wrote a simple program for my TI-85 to do the trig and number crunching. I highly recommend this approach.:)

don1reed

12-23-10, 08:10 AM

I really cannot speak for, Mike, when he and his son originally wrote the Python program for Stellarium; but, it was presumed it was for those of us that had previous knowledge and use of real life, celestial navigation. The genious of his application is that it is flexible enough to be modified along with each new version of Stellarium, either by design or accident.

Apparently it's beginning to take notice. A "build it and they will come" situation.

Sea going celestial navigators took five sights per day, like prayers to Allah, weather (wx) permitting.

1) Pre-dawn twilight--A round of three stars, moon, or planet. Make sure your chosen celestial bodies are spaced about 60〫apart.
2) Ante Meridian (AM) Sun.
3) Noon Sun--when coupled with the AM Sun forms a Running Fix (RFix).
4) Post Meridian (PM) Sun--when coupled with the Noon Sun forms a RFix.
5) Post Sunset twilight--A round of three stars, moon, or planet. Make sure your chosen celestial bodies are spaced about 60〫apart.

Twilight occurs when the Upper Limb (UL) of the Sun is between -12〫and -6〫. The (-) sign indicates that the Sun is below the horizon.

Sun Rise occurs when the UL of the Sun is rising and is precisely even with the Ocean's horizon--NOT when it's half way above the horizon as in the game.

Sunset occurs when the UL of the Sun is dipping and is precisely even with the Ocean's horizon--NOT when it's half way below the horizon as in the game.

When you decide to take a virtual sight while playing SH3/4, pause the game and do a save. Doing this causes the game to write your true geographical coordinates to the save games file.

Open Python enter the date and time, in Greenwich Mean Time (GMT) within their respective focus boxes. All time for navigation is done by Greenwich time. After entering the time, Python should automatically open Stellarium.

I'll continue this post when I get to a PC. I'm currently using an iMac and don't have my files readily avail.

don1reed

12-23-10, 09:51 AM

Taking a real life sextant sight can take anywhere from 30 seconds to 15 minutes...depending on the weather (wx). Under bad conditions, it's impossible.

What the navigator is trying to do is simultaneously view the horizon and the heavenly body. The celestial body is reflected into his field of view by two small mirrors while he adjusts the micrometer drum (the dial at the bottom of the index arm), precisely when it appears as if the body is resting on the horizon, he yells, "MARK", loudly if very windy. His assistant/time-keeper, annotates the time in the navlog by Hour:Minute:Second. The Nav then calls out the Angle of Elevation (read from the Arc at the bottom of the sextant), to the assistant, who jots that info into the log as well. After gathering enough sights, (Five or more for the Sun for an average), they head below or out of the wx to begin their sight-reduction.

Two things needed for Sight-Reduction:

Current Almanac and Sight-Reductions Tables. In RL that could be HO Pub 229, HO Pub 249, or HO Pub 211. Or, if mathematics is your game, by the following two formulae:

Hc = asin [(sin Lat sin Dec) + (cos Lat cos Dec cos LHA)]
Z = acos [( sin Dec - sin Lat sin Hc) / (cos Lat cos Hc)]

What is needed to make your sight in the game:

1) Select a body, pause Stellarium program, jot down the HH:MM:SS and it's Altitude.
2) Resume Stellarium, Select another body, pause Stellarium, jot down theHH:MM:SS and it's Altitude.
3) Resume Stellarium, Select another body, pause Stellarium, jot down theHH:MM:SS and it's Altitude.
4) Exit Stellarium,

From Almanac:

Get:
Sidereal Hour Angle (SHA) of Aries and Declination (Dec) if using Stars,
Greenwich Hour Angle (GHA) of Sun, Moon, & Planets.
Minute/Second Increments
Add them up by xxx° xx.x'
Add East Longitude (Assumed Long)
Subtract West Longitude (Assumed Long)
Answer = Local Hour Angle (LHA)

Use Angle of Elevation from Stellarium as the "Ho" (Observed Height)
(In RL several corrections are needed to discern the true Ho) We won't need to make corrections when using Stellarium.

From the Sight-Reduction Tables:

Get by Assumed Lat, LHA and Dec:

Hc d Z
Hc = the scientifically calculated Altitude of the body.
d = declination correction.
Z = Azimuth of the body.

If Ho > Hc, then subtract Hc. The difference is the distance in nautical miles your line of position (LOP) is in the direction toward the observed body

If Hc > Ho, then subtract Ho. The difference is the distance in nautical miles your line of position (LOP) is in the direction away from the observed body.

From an Assumed Position (usually an intersection of the Assumed closest Lat/Long) construct a intercept line the length in Nautical Miles toward or away from your Zn of the body. At the end of this intercept line, construct a perpendicular line which will represent your LOP.

Continue this process until all your celestial bodies are done this way. When finished, all your LOP will cross in one position or pretty close to one spot. This spot is your Sight-Reduced position.

In theory that's how it's supposed to work. Your results may vary.... :DL

don1reed

12-23-10, 10:07 AM

Purist may complain that I've paused both my game and the Stellarium clock in order to obtain sight reduction.

Consider this before passing any judgement:

1) In RL the skipper was not the navigator aboard the Sub/U-boat. In RL the clock does not stop for anyone. So, if you want to simulate the navigator's chores, you must stop the game because the two programs are not synchronized., unlike doing your own tax return, small arithmetic errors may cause death, both simulated and in RL.

2) Cheers and have a great Holiday everyone.

TorpX

12-23-10, 03:55 PM

Thanks Don for your technical help and expertise. :salute:

I am starting a new career and am determined to rely on the stars come what may. I may get lost and cruise around in circles aimlessly, which, come to think of it, happens a lot anyway. :haha: After all, what is the worst that can happen? :dead:
Anyway, we are due to shove off Dec. 2, 1941, from Cavite. We are taking on a full load of torpedos, but the Admiral assures us this is just a precaution................ the Japanese wouldn't dare attack. :shifty:

Merry Christmas!

Pisces

12-23-10, 05:10 PM

...
If Ho > Hc, then subtract Hc. The difference is the distance in nautical miles your line of position (LOP) is in the direction toward the observed body

If Hc > Ho, then subtract Ho. The difference is the distance in nautical miles your line of position (LOP) is in the direction away from the observed body.
...

You forgot to mention that mnemonic you figured out: Ho-Mo-To-Wo, or Ho More To-w(o)ard. It's very catchy, I'll never forget. It has gotten stuck in my head, only being surpased by saying "Jawohl, Herr Kaleun!" to myself all the time ... for no appearant reason. :88)

don1reed

12-23-10, 10:50 PM

6SJ7GT

12-23-10, 11:33 PM

Greetings, It's been a while, but I see things are picking up again on this thread.

Looks like Don laid out the procedure very well. About the only difference is that I leave stellarium running, and consider the small differences as the randomization that was talked about earlier in the thread. My readings are a minute or 2 apart, and at 9 kts the sub would only move .9 NM.

Also, I record the ALT and time, with both clicking away I sometimes get a little error from this, which I chalk up to rough seas. Just got a new computer and its been fun getting things running again. Mike.

don1reed

12-24-10, 08:02 AM

Well hello, Mike!

You're absolutely correct about the "Keeping Stellarium running".
I was giving them baby-steps....my bad:DL

Where have you been?

Pisces

12-24-10, 02:28 PM

TorpX, you might want to try some local Chicken Adobo before shoving off.
Cheers

Pisces: I almost put it in my explanation...but thought, Nah, they wouldn't understand....LOL. They taught you that phrase too...small world.:rock:

Happy HolidaysNo, you did. My knowledge of CelNav started here on this forum, and from what I already knew about the sky from my interest in astronomy. I've never held a real sextant in my hands, unfortunately. :(

TorpX

12-24-10, 03:57 PM

No, you did. My knowledge of CelNav started here on this forum, and from what I already knew about the sky from my interest in astronomy. I've never held a real sextant in my hands, unfortunately. :(

Same here. I did well in high school geometry (Euclidian), but spherical geometry and celestial navigation are new to me.

On a related note, I have to ask, am I the only one who has trouble getting the helmsman to steer a proper course? My DR positions seem farther off than I would have guessed.

Helmsman, steer 055.
Yes sir! Course 053.
Helmsman, come to course 055.
Aye, sir! Course 056.
Helmsman, I ordered course 055!
Yes sir! course 054.
HELMSMAN! I'M ORDERING YOU TO STEER COURSE 055!
Yes sir, course 056
.............

Captians Log: Dec. 4, 1941
14-36N, 72-28E speed 10.5 knots, heading : Northeast :x

don1reed

12-24-10, 05:05 PM

Dang, Pisces, you're making me feel like "johnny appleseed". I'd forgotten that I told you about HOMOTO. Just another sign of old age, I suppose. lol

TorpX: The F5 screen in the game is not based on a true Mercator Projection Chart. The Developers had to come up with a system to be able to fit the ocean on your display.

This is why it's imperative to do a save every time you take a sight. Saving, updates your boat to it's true Lat/Long, so when you view the celestial canopy in Stellarium, you are seeing the heavens as if you were really at that location in RL.

In the game, DR positions are always wrong. Unless....

you fudge the numbers.

In RL, if I travel @ 10kn. for x hours, I can measure 10 nm along the Latitude hacture marks on the left or right side of my chart with a pair of dividers, then walk the dividers along my drawn course line to see where my DR position is. You cannot do that with the F5 charts of SH3/4/5.

To compensate, you can use the formula

Nautical miles x cosine (whole degree) Latitude = distance.

i.e.,

In RL I'm making 10kn for 5 hours . Distance = Speed x Time = 50nm
In game 50nm x cos 28* = ~44nm.

I used 28 degrees as an example. I play SH3 predominately so lets say I'm near Fair Isle in the North Sea and my Assumed Lat is ~59 degrees, then the formula would reveal:
50nm x cos 59* = ~26nm.
~26nm is the distance I would travel in the game at a speed of 10 knots for 5 hours.

Since we're dealing with deducted reckoning it's the only way I've been able to fudge the numbers to get my DR position.

TorpX

12-24-10, 07:18 PM

Don1Reed:
You have given me a lot to think about. I never expected the charts to be precise and accurate representations of a spherical earth, but I figured by the 4th generation sim, they would be approximately correct. If I understand you correctly, the SH4 charts are, to use a technical term, FUBAR. Some careful checking is in order. :hmmm:

As a footnote: I read what you wrote in an earlier thread about Sh1.
I had a similar experience. I discovered by accident that the distances were grossly messed up. As I recall the island of Borneo was about half it's RL size. :nope: I ended up tabulating the figures into a table for each patrol zone. I have to admit, that error in the game really bothered me a lot. What is so difficult about making a degree of latitude 60 nm?

don1reed

12-24-10, 07:39 PM

Roger that, TorpX.

An easy way to test, at least, it's what I did with SH3 was use the "in game" ruler tool to measure the distance between Meridians and also between Parallels. It doesn't stack up to a real Mercator projection chart. :hmmm:

So most of the time I make my own (Paper) 2° x 2° charts to annotate my progress using Mary Blewitt's instructive book, CELESTIAL NAVIGATION for YACHTSMEN.(about $13.00 US) (Still Avail via Amazon via Subsim). I highly recommend her book. During WWII she taught many Navy and Airmen how to nav.

6SJ7GT

12-25-10, 05:11 PM

Like a lot of Sh4 navigators, I did not know a lot about celestial navigation when I started this project. Here are a few links that helped me understand the process.

Celestial Navigation Net (http://www.celestialnavigation.net/) - Lots of info here. The Theory and Practice pages are especially helpful.

Ed Falk's tutorial (http://www.efalk.org/Navigation/) on a leg of the silicon sea cruise is one of the best basic tutorials I have found.

Universal plotting sheet (http://www.mobilegeographics.com/biblio/Resources/upsa.pdf) for 81/2 X 11 paper (pdf)
To use this one, draw your longitude lines by using the degree scale. if you are at 21d latitude, your verticle (long) lines will be thru the 21d marks above and below the middle latitude line. draw a light diagonal line up and to the right in the bottom right lat-long box. A divider held horizontal from the respective latitude minute marking to the diagonal will give the respective minute of longitude for measuring.

Graph paper printer (http://download.cnet.com/Graph-Paper-Printer/3000-2064_4-10037453.html) - mercator paper is under scientififc types. A real find, this program is useful for almost any type of graph paper you need.

Here is a method of using lined paper to construct a plot sheet:
Use lined paper, college ruled, Turn the paper 90d, so the lines are vertical.
Ruled lines are used for longitude. Every sixth or twelfth line is darkened to
represent a whole degree of longitude. (depending on the scale desired).

Lines of latitude are added by construction, starting with the lowest latitude
desired. Whole degrees are 60 miles.

From your lowest Latitude line, at the most R/H longitude line, draw a line at
an angle up from the Latitude of your lowest latitude line plus a
0.5d(i.e. 28.5d). For ten miles to each vertical line use 6 lines; for 5 miles
to the line use 12 vertical lines. Where the angled line crosses your 6th and/or
12th line swing an arc until it touches your R/H vertical longitude line. This
is the point of the next latitude line. Draw a line perpendicular to the
longitude across the page. Repeat the process with each higher latitude (29.5d),
etc.

The bottom angle line, where it crosses the intermediate vertical longitude
lines, is the distance interval. 10 miles each line for 6 line spacing. 5 miles
each line for 12 line spacing. This forms a handy scale of miles or minutes of
latitude.

The accuracy is within the tolerance of your #2 pencil point.

I have also found that the game map has the tools needed to plot your position, but you need to do this on paper until you get the hang of celnav.

Note that when using Stellarium to take star sights you don't need any altitude or sextant corrections, simplifies things a little in comparison to the above tutorial.

6SJ7GT

12-25-10, 05:32 PM

Forgot to mention some tools you will need for starters:
A ruler
Dividers
Protractor
later you may want a parallel ruler.

You can download the maritime or aviation sight reduction tables here (http://msi.nga.mil/NGAPortal/MSI.portal?_nfpb=true&_pageLabel=msi_portal_page_62).

And when you are thoroughly confused by celnav you can get the Maneuvering board manual (http://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNM/pub1310.zip) and start on that.

Mike 6sj7gt
(http://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/RNM/pub1310.zip)

TorpX

12-30-10, 09:03 PM

This dead reckoning business has proved to be harder than I anticipated. I have been playing around with the school mission to try to see what might be done about it.

First, as measured by the in-game ruler, the degrees of lat. are 64.7nm. The deg. of lon. are also 64.7nm. The meridians do not converge at all, end of story. In other words the earth is flat. At least, this is consistant.
The speeds given by the HUD knotmeter are too high. In a S-18 class boat going standard gives a reading of ~10.4 when you are moving 10.0 kt. Figures for other speeds were similer. This includes submerged movement. While not entirely consistant, I would suggest multiplying the displayed speed by .95. I did not use the helm position knotmeter as it gives even higher values: At std, the helm dial would be about 10.7 or 10.8, the HUD dial would be about 10.4, and the actual speed 10.0.
The HUD compass is very hard to read, and in my set up, at least, seemed to be off a good 2 degrees. The heading, as stated by the crew, seemed to be accurate to within a degree. I experimented with three ways to get the most accurate heading. None of them were very satisfactory. Using the HUD dial was terrible, using short waypoint lines did not work well, even putting the boat on a grid line and using the permanent protractor (a RFB thing, I guess) gave uneven results ( and would be extremely impractical anyway). All things considered, going by the crew statements, seems the best. A heading within .5 deg. is about the best you can hope for with the game as it is now.
Though few using cel-nav will be using the waypoints, I happened to observe some things that might be of interest. I found that the helmsman does not steer a constant heading between waypoints. If, for example, you put two wp's a long distance apart on the equator, say 120 or 240nm, go to high TC, then slow down to zoom in, you can find yourself 1 or 2 nm off course. As you near the next wp, increasing corrections would be made to the heading to reach it. This becomes more obvious, if you place a distant wp, then, after the rudder has reached 0, order the crew to steer a constant course, go to high TC, and see how far off you are as you pass by the wp. Evidently, the game designers didn't contemplate any need for precision here.

I should point out here, that I tabulated these figures in calm conditions. There were no wind or weather factors involved. Rough seas are bound to make speed estimates much harder.

All and all, I think the in game compass and nav tools leave a lot to be desired, but would like to hear from others. I presume Sh3 captains are, excuse the pun, in the same boat. I have some other ideas, but want to use all of this in the game some more.

don1reed

12-30-10, 10:42 PM

Chalk it up to drift and/or set.

Actually 2nm (4000 yds.) isn't that bad for DR navigation. If your bridge is 20' asl you can see the horizon out to 5.2nm (according to Bowditch). So, if your trying to make landfall, 4000 yds. is in the ball park. If it's dark, layoff, till twilight, then make your approach.

Alas, with SH1, raising the scope (high-scope) 60', you could see over the horizon, out to 9.1nm.

If you dissect, Mike's brilliant script for Python, you'll notice that the formula for determining your true game Lat/Long, located in SH4...\Save games, are numbers divided by 120,000. This is what converts the numbers generated by the game's engine into Lat/Long that are usable for navigation purposes.

Every time you do a "Save" your true location will be updated. Real Live navigation is accomplished on Mercator Projection Charts. The games navigation is modeled on something the Dev's invented to fit the F5 chart on the player's screen.

I do most of my chart work on plotting sheets. I annotate the F5 screen with "X's" wherever my "fixes" allow. Usually my fixes and where the game shows me to be are pretty dang close. Admittedly, DR in the game leaves an awful lot to be desired; but, taken on the whole, I'm very entertained with the Silent Hunter franchise.

Happy New Year.

TorpX

12-30-10, 11:22 PM

Don Reed,
I think you misunderstood my post. I was only holding to within 1 or 2 nm by using the in-game waypoints, a major cheat really. This was just to check actual speeds vs. indicated speeds. I agree 1 or 2 nm at the end of a long day of cruising going by DR would be great. But with the lack of precision in the compass or knotmeter, I doubt I will get anything like that 'in play'.

Since you're here let me ask you, if you were starting from a known position and cruised for 24 hrs at 10kt with only, lets say a few course changes, how far off would you expect your DR position to be?

I was considering printing some maps out, and maybe I will, but would prefer to keep the extra "paperwork" to a minimum.

I don't mean to sound negative though, Sh4 is the best game I know of. Otherwise, I wouldn't be making the effort to do this.

Happy New Year!

don1reed

12-30-10, 11:36 PM

Yes, I misunderstood your post. :)

In real life, D = S x T. 10kn x 24hrs = 240 nm

In the game, 240nm x cos (Lat) = _____

what Lat are you in?

If you're on the Equator, then, 240nm.

@ 1 degree Lat, then 239.9nm,
@ 30 degree Lat, then 207.8nm,
@ 45 degree Lat, then 169.7nm,
@ 60 degree Lat, then 120nm.

Distance x cos (Lat) is what I use in SH3...and it keeps me in the ball park.

I play time x1 and I take 5 sights per day and connect the dots (fixes). I use the measurement tool with compass to set my course between fixes and waypoints, in order to keep my boat headed for points on the ocean that the game understands.

In real life you could use the "Great Circle" formula to set your course between point A and B. On a Mercator Projection chart, a Great Circle course is a curved line. On a Gnomonic Projection chart, a Great Circle course is a straight line. If you have a desk globe and a piece of string, you can put one end at San Francisco, as example, and the other end on Japan. When viewed top-dead-center, the string appears as a straight line, and a curved chord from a side view.

What is happening in the game, is the curving of the course line which is transparent to the player.

To expand on the Gnomonic chart a bit further, absent a Navigational computer, mariners would use a Gnomonic chart to fashion a straight line course, paying sharp attention to where the course intersects with major latitudes and longitudes. These course Lat/Long crossings are then transferred to a Mercator Projection chart. Once layout is complete, it can be seen the course is curved and where course changes will occur on the Mercator chart as separate, short legs. A succession of straight, connecting courses, called Rhumb lines. (almost like calculus :) ) The overall effect appears as a curved course. I have not tried it yet, lacking a desk globe, but, I don't see why it wouldn't work for our purposes in the game. At least, you'd be able to see why the course changes between your waypoints.

6SJ7GT

01-02-11, 11:34 AM

Interesting discussion.

When I researched the game, I found that the devs measured E/W, then N/S in yards from 0d north and 0d west. They also used 2000 yds as a Nautical Mile. Thus the 120000 figure for a degree of latitude or longitude at the equator. Since an actual nautical mile is 6076 feet this might explain some of the errors vs real life in long distance navigation.

By moving first along the equator then N/S, you can translate your position to a flat map, it would create problems measuring E/W at places other than the equator, though.

Mike 6sj7gt

TorpX

01-17-11, 04:35 PM

If anybody is still checking into this thread, I'd like to know how many people are using this or how many have tried it. This goes for both Sh3 and Sh4. I would be interested in hearing about their experiences.

Anybody?

don1reed

01-17-11, 05:13 PM

I've been using it ever since, Mike, first posted it for SH4 and later converted it for use with SH3.

Sadly, I have not yet found a way to use with SH5.

A lot of folks have problems with SH3 due to the "drifting" and/or "sleepy helmsman" and probably don't use it that much on that game. Since I play TC x1 primarily, that gives me time to "whack" him when he falls asleep, to keep him on course.

Biggest problem is with the F5 screen Chart, particularly with DR in latitudes N and S where longitude degrees are significantly narrower than 60nm.

Lately I've only been using three star fixes obtained with pre-dawn and sunset twilight. Running fixes (RFix) using the Sun requires a DR more equivalent to one that could be obtained in real life. This results in an "UNSAT" RFix.

Using the Three star Fix usually puts me right on the money.

Armistead

01-17-11, 07:23 PM

I'm goin' down

01-19-11, 11:20 PM

you made it further than me. I cannot figure how to navigate. I need a video or an ELEMENTARY tutorial.

TorpX

01-20-11, 11:31 PM

I did for awhile, but it takes sometime and in itself can become the focus of the game. The coming in and out to use the program is a task. You eventually become so wrapped up in it you forget fighting.

This is pretty much my view of it. I did it for a little while, but found it absorbed a lot of time and energy. I would like to be able to play through a week or so, if things are quiet. As it was, after a day or two, I didn't really want to find a contact.

I do like the concept though. If there were better in-game tools or, put another way, fewer obstacles in Sh4, I think it could be a viable proposition. As it is, it's a tough row to hoe.

In any case, a have a few ideas in case there are modders who would like to develop the approach further:

Create some kind of dead reckoning indicator in the game. With the game as it is now, you have a choice between knowing exactly where you are (I don't need celestial navigation), and having no idea where you are (I'm hoplessly lost). Trying to account for every course change, speed change, evasive maneuver or weather effect is too much work load, IMO. Also, the player needs this to make an in-game tactical plot when the time comes.
Have a "navigator" in the game, where your position could be calculated automatically, with a reasonable degree of error (say 3 to 5 nm, weather permitting), so the player does not have to do it every single day.
Mod the charts/terrain so that prominent mountains and landmarks could be used to a greater extent. If mtn peaks were accurately marked on the charts (both location and elevation), they would be useful. Same for lighthouses (and maybe a few distinctive features here and there). The Sh4 generic land, in the game doesn't help the cause.
Of these, I consider no. 1, to be the most important, but I'm guessing, also the most difficult (or perhaps impossible). When I was using this approach, I found I could do the star fixes (tho it took more time that I wanted), but the dead reckoning business was torture. Definitely, its the worst part.

don1reed

01-21-11, 07:38 AM

At least, for those who have tried it for the first time in their lives, it gives one an appreciation of the state of the art of navigation in the 1940's. It demands a lot more than -- point and click.

Yes, it takes the focus away from the point of the "game" if you must rely on volumes of Tables (HO Pub 211, 229, or 249) or the ephemeris provided by Mike's almanac for the war years. I breeze through the calcs, admittedly, as I use professional computer programs for navigation, who's database covers two centuries. For me it's a simple matter of just entering date, time, Ho, Assumed Position, and selecting the appropriate body. The program(s) spit out the correct Lat/Long every time.

I agree, Torp, that the DR in all series of Silent Hunter "game" is hosed...fubar.

My dream would be able to use a virtual sextant (a second use for the Observation periscope, perhaps).

TorpX

01-21-11, 09:10 PM

At least, for those who have tried it for the first time in their lives, it gives one an appreciation of the state of the art of navigation in the 1940's. It demands a lot more than -- point and click.

Yeah, I admit I'm a little lazy.

Yes, it takes the focus away from the point of the "game" if you must rely on volumes of Tables (HO Pub 211, 229, or 249) or the ephemeris provided by Mike's almanac for the war years. I breeze through the calcs, admittedly, as I use professional computer programs for navigation, who's database covers two centuries. For me it's a simple matter of just entering date, time, Ho, Assumed Position, and selecting the appropriate body. The program(s) spit out the correct Lat/Long every time.

Ahhhhhhh.......... That would help.

I agree, Torp, that the DR in all series of Silent Hunter "game" is hosed...fubar.

Yes, but I do admit it has one BIG advantage over my earlier fav, SHCE; I can actually sail accross the Pacific. I really didn't like being confined to a virtual aquarium.

My dream would be able to use a virtual sextant (a second use for the Observation periscope, perhaps).

Maybe there will be a Silent Hunter VI. :-?

6SJ7GT

02-08-11, 11:32 PM

I uploaded the SH4 Nav package to the SH4 mods in the files section.

This one has updated Nautical almanacs (still the same information, just a different look as I generated them directly to pdf from python).

It has some other goodies, including an Excel sheet that plots a 3 star fix.

Cheers,
Mike 6sj7gt

don1reed

02-08-11, 11:38 PM

Great job, Mike:yeah:

don1reed

02-09-11, 10:01 AM

Full disclosure, Mike. I mistakenly referred to Gnomonic chart as Conic in our last email.

An here is the reason DR doesn't work in the games:

from HO Pub No.9 The American Practical Navigator a.k.a. Bowditch, 1995

http://img189.imageshack.us/img189/8256/gnomicchart.jpg (http://img189.imageshack.us/i/gnomicchart.jpg/)

A Gnomonic chart provides the navigator a GREAT CIRCLE course. When laid out on a Mercator chart it becomes a curved course made up of many, small, Rhumb line courses. It provides the navigator the shortest distance course between two points...in case some of you have been wondering why you've been running out of fuel in operation Paukenschlag [sic] when crossing the Atlantic.

Soooo....every time you construct a long straight line course (>600 nm) on the F5 chart (which is made to look like a Mercator, but really isn't) you are going many extra miles out of your way to get between the two locations.
Proof: That straight line course on a Mercator chart, is now a curved course on a Gnomonic chart. (they are inversely proportional).

Simply put, the F5 chart is not a Mercator Projection chart and it makes DR navigation very difficult.
Uploaded with ImageShack.us (http://imageshack.us)

TorpX

02-09-11, 12:13 PM

I just read your post don. I don't understand it at all.

I know a great circle route will not be a straight line on a mercator chart, and that this is vital in real world navigation. But I don't see how any of this applies to SH3/SH4. When I checked distances in SH4, I saw clearly that the meridians do not converge anywhere on the map. One degree of lat. or lon. is the same distance everywhere. For all practical purposes, the SH4 world is flat.
Perhaps I should say it's cylendrical, as you can go around the world east to west, but as I said above, every grid square is the same size as every other in the game.

Have you tried to verify your gnomonic idea?

Unless I am very much mistaken, your marked route from San Francisco to Yokohama, will add many extra miles to your cruise in SH4.

don1reed

02-09-11, 12:41 PM

We're on the same sheet of music, Torpx.

The F5 screen chart IS NOT, I say again, IS NOT a Mercator projection chart.
If it were, then the mathematical rules would apply for Distance = Speed x Time, and they don't.

A Real Mercator projection chart compensates for the longitudinal convergence by making the space between them longer, as they approach the poles.

I feel your pain.

don1reed

02-09-11, 01:00 PM

Have you tried to verify your gnomonic idea?

If you mean, Have I tried making a Great Circle course across the Atlantic?

Not in the game, but, I have used the "idea" in real life.

For Straight Line distances > 600 nm, it's a necessity at sea to make a Great Circle course. If you fashion a straight line course on a Mercator chart for long distance, you'd wind up going miles out of your way. This is why some players have run out of fuel crossing large bodies of water in the game.

You can prove this to yourself with a "desk globe".

Hold a piece of string between New York and England, pulled tight to the globe. That string represents a Great Circle course. Now, carefully, note where the string crosses meridians and parallels. Annotate those locations on a Mercator chart. You will now have a curved course to follow, which must be broken down into smaller, straight, Rhumb line courses. Even though the course now appears curved, it is the shortest distance between two points.

Rule of thumb:

If straight line course is N of Equator on a gnomonic chart or globe, it will curve toward the North on a Mercator chart.

TorpX

02-09-11, 01:21 PM

If you mean, Have I tried making a Great Circle course across the Atlantic?

Not in the game, but, I have used the "idea" in real life.

For Straight Line distances > 600 nm, it's a necessity at sea to make a Great Circle course. If you fashion a straight line course on a Mercator chart for long distance, you'd wind up going miles out of your way. This is why some players have run out of fuel crossing large bodies of water in the game.

I'm not disputing your expertise or anything your saying as it applies to real world navigation, I just don't see how it factors into the game. The SH4 world is a computer generated illusion, and everything I've seen in the game has led me to think that, they simply didn't consider it worthwhile to incorporate a sophisticated spherical model. They instead decided to use the simplest and easiest model, which is a "flat earth". Unless the model used was purposely designed to simulate what you describe, I don't see how it could occur.

don1reed

02-09-11, 01:36 PM

I know that, Torpx. :)

I'm saying:
1) Dead Reckoning doesn't work in SH3 or 4.
2) Celnav does work...as far as locating your position by three body fix.
3) RFixes only work when using two timed bearings on landmarks over short, line-of-sight distances.

I've quit trying to use DR in the games...too frustrating at my age. :)

cheers,

TorpX

02-09-11, 01:45 PM

1) Dead Reckoning doesn't work in SH3 or 4.
2) Celnav does work...as far as locating your position by three body fix.
3) RFixes only work when using two timed bearings on landmarks over short, line-of-sight distances.

I've quit trying to use DR in the games...too frustrating at my age. :)

cheers,

Yeah, I gave up on it too. DR was an exercise in frustration. :damn:

fitzcarraldo

03-29-11, 09:44 PM

Where can I download the files of this realnav? I downloaded the Stellarium program, but the rest of files, all links are death...:wah:

Many thanks!

Fitzcarraldo :salute:

6SJ7GT

04-02-11, 08:36 AM

Fitzcarraldo,

I uploaded the package to the SH4 gameplay mods on this site.

look for the SH4 Nav Package (http://www.subsim.com/radioroom/downloads.php?do=file&id=2991)

Cheers,
Mike 6sj7gt

fitzcarraldo

04-02-11, 08:44 AM

Fitzcarraldo,

I uploaded the package to the SH4 gameplay mods on this site.

look for the SH4 Nav Package (http://www.subsim.com/radioroom/downloads.php?do=file&id=2991)

Cheers,
Mike 6sj7gt

Many thanks, Mike! Downloading now :yeah:

Regards.

Fitzcarraldo :salute:

Daniel Prates

04-14-11, 03:52 PM

fitzcarraldo

04-14-11, 04:49 PM

Just a literature tip: LONGITUDE, by Dava Sobel. One of the best books I ever read about this subject. It covers the famous 'longitude problem' of centuries ago, the various attempts of solving it, and how a clock maker eventually nailed the prize. Of course, it is a history book, not a techical one.

Many thanks for this literature tip.:up:

Only I need a sextant in my SH4...I dowloaded the pack for celestial navigation, but I don´t have the sextant. I read the thread about the sextant in the Obs. periscope, but I like a simple sextant-rule as that I have in SH3.

Where is that sextant, if it exist?

Best regards.

Fitzcarraldo :salute:

Pisces

04-15-11, 07:28 AM

Many thanks for this literature tip.:up:

Only I need a sextant in my SH4...I dowloaded the pack for celestial navigation, but I don´t have the sextant. I read the thread about the sextant in the Obs. periscope, but I like a simple sextant-rule as that I have in SH3.

Where is that sextant, if it exist?

Best regards.

Fitzcarraldo :salute:In this thread it is called "the program Stellarium"!

fitzcarraldo

04-15-11, 07:37 AM

In this thread it is called "the program Stellarium"!

OK, I use Stellarium, but it is an external program. I speak about a sextant-rule style mod for SH4, as the Real Navigation Mod for SH3.

Many thanks and regards.

Fitzcarraldo :salute:

Pilot_76

10-26-11, 02:28 AM

OK, I use Stellarium, but it is an external program. I speak about a sextant-rule style mod for SH4, as the Real Navigation Mod for SH3.

Many thanks and regards.

Fitzcarraldo :salute:

I am really eager to start this Stellarium/SH4/SH3 "partnership" but I still have much to learn. What I've dug so far is that sextant mod works only for SH3, SH4 v 1.3. I tried to install it on the 1.5 version but with no success. Besides reading all these posts I agree that Stellarium is a much better tool and has more immersion so I am almost giving up the idea of using the Sextant mod at all.

Some doubts I have:

-How is it possible to remove completely our sub from the map? The no sub map mod partially does it.

-Is DR only good for ranges <600nm?

BTW: I posted a comment on WOTA's facebook page suggesting Cel Nav as an option. He got very interested. Feel free anyone to go there and support this thanks. WOTA is a SH version for iPad/ iphone (in other words, what Ubisoft chose not to design).

Castorp24

12-28-11, 03:40 PM

Thanks for the good work! :salute:
I recently uploaded a little modification that finally gets rid of ANY trace of the sub/ship in the navigation map (no tails, no little dots). Now it is just impossible to locate visually the thing in the F5 chart.

Download link here:
http://www.subsim.com/radioroom/showthread.php?t=190956

castorp345

01-26-13, 11:12 PM

Here's an update to Michael Jones' brilliant python script to include randomization-based error derived from sea state and own speed, as well as to work with Stellarium 0.11.4.

Please note that the attachment as included here needs to have its .txt extension removed (leaving just the .py of course), and that you need to edit the script to include your own proper directory locations!

Also, be sure to input the correct syntax for the date (yyyy:mm:dd), and UTC time (hh:mm:ss), otherwise the script won't load properly into Stellarium.

Many thanks, Michael, for your original work and for providing such a great & fun way to practice plotting fixes without having to lug my C. Plath around! :D
cheers,
hc
:salute:

Pisces

01-27-13, 06:18 AM

I think the randomization is better applied to the individual altitude measurements. As that is what will be complicated by wind and sea motion. The randomization is now applied to the viewing location in this script. And so applies to all observed objects in the same way. But I understand this is not really possible to program into the startup-script. As it should be a post-fix correction.

Personally I would limit myself to the amount I can zoom in on the object (to simulate the amount of wobble in holding my sextant), and guestimate by eye at what distance it is at from the nearest altitude gridline in Stellarium. That means 3 individual opportunities for measurement errors. Increasing and distorting the size of the position-probability-triangle. Instead of a single offset applied to all observations making you calculate the position of where you are NOT at.

TorpX

01-27-13, 11:06 PM

Here's an update to Michael Jones' brilliant python script to include randomization-based error derived from sea state and own speed, as well as to work with Stellarium 0.11.4.

Would it be possible to make a script that would use a randomization-based error derived from sea/whether state and perhaps navigator experience, to return 3 lines of position? That is, you would pause your game and save as before, then retrieve 3 sets of coordinates for the LOP's and plot them in your in-game charts, and skip the Stellarium and tables part of the procedure.

I like the concept of navigational error and all, but find the whole Stellarium business much too tedious.

in_vino_vomitus

07-16-14, 04:23 AM

So - Celestial nav is something I've always wanted to learn, so when I found out about this method of using it in-game I was pretty happy. I've no idea how long it will take me to get competent at the maths and so far I'm only using it in the Pacific, but here's something that occurred to me. I have to input the GMT time and date into stellarium via Python, and I'm taking it from the tutorial that Pacific boats run on pearl time, i.e. Z-10, but when I move to the Atlantic or the Med, what's my time zone there? I have a map of time zones, does SH4 adhere to it? Someone mentioned saving a game at local noon and comparing a sun sight from Stellarium, which I'll probably do as soon as I know how :) but I wondered if anyone could save me exercising my mind by answering the question off the top of their heads?

P.S. - I had to use 2008 versions of Python and Stellarium to get them all to work together with the script in the download. I mention this just in case anyone has given up on this because of issues with the current versions. A couple of folks seem to have - Also it shows I read the thread before asking the question :)

TorpX

07-16-14, 09:56 PM

If your asking about SH4, I believe that your time will be your home base local time. In SH3, I have no idea.

Someone mentioned saving a game at local noon and comparing a sun sight from Stellarium...

This is probably a good idea. The game is very strange, and I'm not sure how far we should trust it.

in_vino_vomitus

07-16-14, 11:52 PM

If your asking about SH4, I believe that your time will be your home base local time. In SH3, I have no idea.

This is probably a good idea. The game is very strange, and I'm not sure how far we should trust it.

Yep - I was asking about SH4, thanks for responding. I checked the sun, in the Med campaign and I think it reached it's highest point at 12:33 zulu, which seemed about right for Gib', which is right on the Western edge of the Alpha TZ. Still haven't managed to plot a fix yet, or at least I haven't managed to get a computed height within a degree of the observed height twice in a row - The problem is I'm not sure where the error is. In the real world I'd have access to GMT :(

Still having lots of fun working it out though, and since I started this in the middle of a patrol, it's going to be a real challenge getting back to Pearl without using waypoints :)

Anyway thanks for the info - every bit helps:up: