Celestial Navigation in SH4

[6SJ7GT]

UPDATE:
I have place the tools for this in the SH4 Gameplay Mods on this site.
look for the SH4 Nav Package

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, and takes the sub position in a saved game and transfers it to a freeware planetarium program.

There is a tutorial here if you want to try celnav out.

I have put together the Almanacs and tools needed for plotting in a 7zip here.

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.../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.
******************

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

2. Install Python, this version has the windows extensions: Activestate Python

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 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]

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

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]

This is genius!

[Schultzy]

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]

Originally Posted by Schultzy

You're turning me into a navigation addict.

Glad to see I'm not alone!

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

[6SJ7GT]

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 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

[SteamWake]

Originally Posted by Doolan

Glad to see I'm not alone!

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

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

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

Hi all,

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

Regards,

L

[Pisces]

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]

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

[OrangeYoshi]

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]

You still need to download the most important thing, the Stellarium planetarium program. 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.

[Dutch]

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]

about GMT: I made some custom missions and (I think)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° <-- 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 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]

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/Ce...ion-for-H4.7z/

Almanacs for both SH4 and SH3:
http://www.filefront.com/14996507/19...5-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.