RealNav navigation..

[kevtherev]

Originally Posted by poor sailor

I was tried your advice Georg and found your solution excellent for me! Many thanks!

I tried this also but it does not work for me, maybe I am doing something wrong. I do not however wish to do sextant navigation as for real, I only want to get rid of my own ship indications and try my hand at 'Dantenoc Navigation'. Here goes:-
I am running GWX 1.03 without the 'Real Navigation' mod installed. I have however used the 'no tail' mod
from Georg and also his advice on modifying the map.cfg data. I am still experiencing an indication of
'my own ship' in the form of a circle at all levels of map magnification. Is there any way that I can
get rid of this indication ?



In the examples please ignore the 'planned route' as I am only using this as a trial for the Kiel canal
option !!! Would normally, without own ship indication, be doing the navigation myself.
Mods installed (jsgme) are:-
GWX - 16km Atnosphere
GWX - Capt America's Officer Icons
GWX - English Nav Map and Grid refs.
GWX - Lite harbor Traffic
GWX - Main Movie 'Das Boot'
GWX - No Medals on Crew
GWX - Reduce Positive Buoyancy
GWX - Lower DF antenna
TypeVII_open_hatch
Open_Hatch_peri
Course_tail_removed_from_GWX103

I am not an expert on mods and configs but I do not think that I have done anything wrong ?? Could anyone please help ??

[vanjast]

Originally Posted by kevtherev

'my own ship' in the form of a circle at all levels of map magnification. Is there any way that I can get rid of this indication ?

What you can do is browse through the game folders (usually the Menu one) and have a look for the image containing this circle. When you find this image, edit it with an image editor. As with most SH3 images this image will have 2 layers - Background and Mask. All you have to do is edit the mask layer by blanking/fill it out completely (eg: get rid of the image in this mask). This will 'mask' out the image completely.

If this image is part of an multi-image image (lots of images in one image), do the same to the mask layer but only over this particular section of the image.

That should do it.

[Georg_Unterberg]

Hi kevtherev,

you need the 3 transparent submarkers from vanjasts "Realnav" - mod.
I saw that you didn't install it, so I'll upload the files separately. Note: This will just make your sub-circle disappear.
To get all the other benefits from vanjast, like his excellent Lat/Lon Map and sextant, you'll need to install the full mod.


Hang on a moment.

edit: ok uploaded the 3 files you need. Please install with JSGME

http://files.filefront.com//;7629500;;/

[kevtherev]

Originally Posted by Georg_Unterberg

Hi kevtherev,

you need the 3 transparent submarkers from vanjasts "Realnav" - mod.
I saw that you didn't install it, so I'll upload the files separately. Note: This will just make your sub-circle disappear.
To get all the other benefits from vanjast, like his excellent Lat/Lon Map and sextant, you'll need to install the full mod.


Hang on a moment.

edit: ok uploaded the 3 files you need. Please install with JSGME

http://files.filefront.com//;7629500;;/

Downloaded and installed via. JSGME, works a treat, now I am virtually 'blind'. Great job for me Georg, many, many thanks to you and others who have helped me with this prob.
Although my methods of navigation leave a lot to be desired as regards 'real nav' they suite me at the moment until I can get some understanding of 'celestial and sextant navigation'. Although the nav method I use is not quite 'real' I find that it has another added aspect to this wonderfull sim (SH3 and GWX).

[Georg_Unterberg]

Originally Posted by poor sailor

Well, now I'm starting with this great mod. I learned how to use the sextant, but how to use the sunset/rise table and how to calculate longitude, is there any formula to get this? Sorry, maybe is there in your manual Van, but I couldn't understand well I think.

saw your question, but it's not so easy to explain - it will take a while
(anyone can jump in here and help or correct me)

IMHO the accuracy from sunrise/sunset spotting is not very good. And you only get longitude this way.
You still have to know latitude in some way and therefore you will need the sextant. To use vanjasts
suntables to solve for longitude you must know your latitude approximately to enter the table correctly.

by then the rule of thumb is: every 4min the sun moves 1° from east to west, every hour the sun moves 15°.

so an (maybe not so easy) example:

its 25/May/1943: you are at about 20° S Lat.
You want to know longitude, so you wait for sunrise. At 6:24 ship chrono you see this:



You note: I "estimate" sunrise at 6:24. Now enter vanjast's table to look for sunrise/set page of "Southern Latitudes ".
Look under line 25/may and column 20°S. Note the sunrise time you'll see 6:24 !

You are on spot on either meridian of 0° 15° 30°....... Now note the time difference between ship chrono and local time.
local time is 1 hour earlier, so you are exactly 15° W of greenwich.

Now imagine you saw the sunrise under same conditions at 6:32. Thats 8min later than table time.
So you'll have to add 2 more degrees to the west. Together with 15° W for 1h time difference (local-chrono) that's 17° W.


The hardest part in all this is: you'll always have to wait for the sun!
And I get varying results, maybe it's the way the sun is modelled in SH3. I'm more or less 2min = 30' accurate, that's half a degree.

note: If you travel at e.g. 24° Lat you'll have to interpolate in the table between times for 20° and 30°.

[poor sailor]

Many thanks for your looking to help me to understand how to measure Longitude. Your example is very well and I understand much better now.

[Notewire]

Ok, because I am king of the very simple question -

Do you mark the sun at the top of the sun, the middle of the sun, or the bottom of the sun?

I saw a comment about this in the thread but didn't quite understand.

Thanks,
Notewire.

[vanjast]

Notewire,
In real life the sunrise/set is when the upper rim of the sun just becomes/dissapears above/below the horizon.
The game sunrise/set times are set to when only half of the sun is visible on the horizon. The time taken from upper rim to complete sun is about 4-6 minutes depending on your latitude. The higher the latitudes the longer it takes as the sun travels at a much shallower angle to the horizon.

There is a slight difference in the Mods RL almanac compared to the game times. It can be as much as 4 minutes (1 Degree Longitude). Not a 'train-smash' but as long as you are aware of these conditions.

I have not had time to go over the whole lot as family and RL is on top of me, but will do when I have a break.


From the US Naval Observatory Website

Sunrise and sunset conventionally refer to the times when the upper edge of the disk of the Sun is on the horizon, considered unobstructed relative to the location of interest. Atmospheric conditions are assumed to be average, and the location is in a level region on the Earth's surface.

Moonrise and moonset times are computed for exactly the same circumstances as for sunrise and sunset. However, moonrise and moonset may occur at any time during a 24 hour period and, consequently, it is often possible for the Moon to be seen during daylight, and to have moonless nights. It is also possible that a moonrise or moonset does not occur relative to a specific place on a given date.

Civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 6 degrees below the horizon. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities. Complete darkness, however, ends sometime prior to the beginning of morning civil twilight and begins sometime after the end of evening civil twilight.

Nautical twilight is defined to begin in the morning, and to end in the evening, when the center of the sun is geometrically 12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor operations are not possible, and the horizon is indistinct.


Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 18 degrees below the horizon. Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening the Sun does not contribute to sky illumination; for a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible.

Does anyone of you have any experience with Real Navigation with SH4??

I cant seem to fit the game clock to anything.

fx. New mission build with boat parked outside Pearl Harbor close to a posission 20N 158W on June 1. 1944

Vanjast's Almanac says:

Sun Rise 05:20
Sun Set 18:35

An Almanac program says:

Sun Rise 05:52 @ 66deg true
Sun Set 19:08 @ 294 deg true

StarCalc says:

Sun Rise 05:52 @ 66deg true
Sun Set 19:08 @ 294 deg true

In the game the gameclock (called Base time, and i'd presume thats Pearl Harbor time equal to GMT -10) says:

Sun Rise (half disc visible) 04:52 @ 67 deg true
Sun Set (do.) 18:08 @ 295 deg true

Could it be that Summertime has anything to do with this...?

More weired is the moon phase - this one is way out of sync.
It should set at 02:32 @ 271 deg true, but it was in the game at 02:10 @ 268 deg true.

Could it be that its not the year 1944 that is used in SH??

[Notewire]

Originally Posted by vanjast

Notewire,
In real life the sunrise/set is when the upper rim of the sun just becomes/dissapears above/below the horizon.
The game sunrise/set times are set to when only half of the sun is visible on the horizon. The time taken from upper rim to complete sun is about 4-6 minutes depending on your latitude. The higher the latitudes the longer it takes as the sun travels at a much shallower angle to the horizon.

There is a slight difference in the Mods RL almanac compared to the game times. It can be as much as 4 minutes (1 Degree Longitude). Not a 'train-smash' but as long as you are aware of these conditions.

I have not had time to go over the whole lot as family and RL is on top of me, but will do when I have a break.



From the US Naval Observatory Website

Sunrise and sunset conventionally refer to the times when the upper edge of the disk of the Sun is on the horizon, considered unobstructed relative to the location of interest. Atmospheric conditions are assumed to be average, and the location is in a level region on the Earth's surface.

Moonrise and moonset times are computed for exactly the same circumstances as for sunrise and sunset. However, moonrise and moonset may occur at any time during a 24 hour period and, consequently, it is often possible for the Moon to be seen during daylight, and to have moonless nights. It is also possible that a moonrise or moonset does not occur relative to a specific place on a given date.

Civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 6 degrees below the horizon. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities. Complete darkness, however, ends sometime prior to the beginning of morning civil twilight and begins sometime after the end of evening civil twilight.

Nautical twilight is defined to begin in the morning, and to end in the evening, when the center of the sun is geometrically 12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor operations are not possible, and the horizon is indistinct.


Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 18 degrees below the horizon. Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening the Sun does not contribute to sky illumination; for a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible.

Thanks Vanjast, as an Army guy IRL, we use BMNT and EMNT - (Nautical Twilight, as explained above) - I will start using the game's "half sun" navigation.

Thanks for your time,
Notewire.

[don1reed]

Hi Mav,

I've been using Omar Reis's Navigator pgm and Starpath's Nav pgm on a TI-86 for years. Recently, Mar 2005, with the birth of SH3 I also added StarCalc for gameplay. I never could get the Cel Nav to work on SH3 or even more recently, SH4.

I suppose a way around the "clock" issue in SH4 is to set dead in the water off a known landmark and goto TC and watch and stop the SUN as it makes it's way to Zenith, then make a Noon Latitude/Longitude sight, using your nav pgm to verify the your coordinates...At meridian passage.

Van's niffty nav pgm has opened the doors to find a sure-fire method of finding your fix in the ocean. It's a step in the right direction.

I think i might have the bugger, but it needs a little more investigation.

It seems that forces in the pacific used GMT -11 as a standard, and that corresponds with my initial tests of a "parked" boat outside PEAL HARBOR on June 1. 1944 for both Sun Rise and Set's.

Need to do more testing further from PEARL.

But the timing problems could be that one has to use GMT -11 all over the pacific...

[don1reed]

I'm currently in Time Zone H (Hotel (-8) GMT ), from Fremantle up through P.I. within the game...so far local time is correct local time. Subtracting 8 hrs. gives me correct GMT for navigation purposes.

One loose theory in the binner...

[poor sailor]

Maybe I'm something doing wrong but I have some strange situation on my first serious sailing .

On first picture I found Polaris star (Well, I think that It is )


On second picture I started measures with sextant and found that is ~40 degree


And on third picture is shown where is this value I found with sextant on map


What I'm doing wrong? I started my patrol in Kiel.