Celestial Navigation in SH4

[I'm goin' down]

Why?

[Pisces]

why do we want to use celestial navagation?

Originally Posted by I'm goin' down

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

[I'm goin' down]

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.

[6SJ7GT]

Originally Posted by I'm goin' down

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.

I'm goin' down, You're right that the game has all of the tools you need to navigate. Celestial navigation does tell you where you are, and combined with dead reckoning is what was used pre-GPS to navigate. Adds to the simulation realism to do things the way they were really done on the boats.

FYI, this was even used in overseas navigation by aircraft until about 15 years ago.

Mike 6sj7gt

[Pisces]

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 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 ... 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.

[vanjast]

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

[6SJ7GT]

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]

In one of the downloads there is a link to A Short Guide to Celestial Navigation, 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]

Originally Posted by I'm goin' down

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...

[berobispo]

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 .

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]

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

[Pisces]

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/astron...s/cel-nav-data