Real Navigation Mod files - FINAL

Originally Posted by don1reed

EDIT: As you know, a real sextant operates very similar to the "split image Kollmorgan periscope" in SH4, pity the Dev's didn't go one step further and allow the scope to elevate to 90° so as to measure the angles of the celestial bodies in the heavenly canopy.

That is not a problem if you desire it to be so......

a small simple change to one of the scopes in the camaras.dat file...


Im not sure what you ment with the calculations - could you make the example with these numbers Don1 ??

Game data:...............................Star Calc for the day

Sun at set - 08:26:00.............06:36:00
Noon - 13:47:00.............11:47:00 height 41 deg's
Sun at down - 18:59:00.............16:59:00

[don1reed]

@Mav:

Split image: A way to register degrees of elevation is needed and a way to make the split image function work without being centered "L key" on a ship.

-...-

Meridian time: (This is just an example of my suggestion)

Local date : 4 Feb 42
GMT date : 3 Feb 42

Location: 33° 37' N, 139° 21' E

Sunrise: 06:12:00 base time
Sunset: 17:14:49 base time

17:14:49
-6:12:00
11:02:49 = # of daylight hrs. divide in half = 05:01:24 add this to sunrise time = 11:13:24 <----this is real noon time in the sim if the sun is bearing 180° (true).

Further explanation: At Sunrise-Sunset...

The center of the sun is actually 50' (or 0.83°) below the horizon, the upper limb is 34' below the horizon.

So in the case of SH4 we have

Sun Set (center of sun)...18:59:00
Sun Rise (center of sun).-08:36:00
...................................10:23:00/2

.05:11:30
+08:36:00
13:47:30 witch is 1hour 47min 30sec different from the timezone noon at 12:00:00

the location is 30¨00'00 E and 150¨00'00 N Time Zone K= +10 hours

+10 hours
+1 hour 47min 30 sec
is +11 hours 47 min 30 sec of time difference to GMT

aka sunset at this spot should be at 08:11:30 GMT

Now im not really sure how all that corrosponds to where my position is. Don....

[don1reed]

Yeah, Mav, I came to the same conclusion. I was heading back to Pearl from patl off Honshu and came to "all stop" precisley at 32° 08'N, 150° 00' E, (the meridian acctually crossed the tower) and my SR/SS and LAN times were about 1 to 2 hours off from a real Navigation program I also use. My LAN (Local Apparent Noon) was 14:20 (Base time). I presume that the internal game clock will vary throughout the Pacific at this rate.

Navigation with that amount of error is strickly UNSAT. (You will not receive a "GO" at this station.)

If there is a "fix" for this anomoly, it may entail making the same experiment at each and every time-zone (Longitudes evenly divisible by 15). Without accurate time and/or the celestial canopy moving in sync with accurate time for the war years, there can be no precise navigation. I still have a sneaky suspicion that heavenly overlay in the sim is nothing but eye-candy.

What van did, IIRC, is tc through the sim (SH3) and compiled a table based on the red-light in sim turning on/off, indicating SR/SS. This as we know varies from real sr/ss or when a real navigation pgm says sr/ss occurs, they are not in sync. I believe that I read somewhere in this thread that "someone" should attempt to follow the same procedure to compile a sr/ss table for SH4 as well.

...or, has most of the work been done?

Did the Devs incorporate the celestial canopy used in SH3 into SH4 also? I presume they did, due to the quickness of putting SH4 onto the market...same engine...different part of the world.

[don1reed]

Here's an interesting pic of UL sun just dipping beneath the waves. My location: 28-15N 177-32W. What you see is the orange after-glow. The defined circumference of the sun has just disappeared.

Note the time: 18:45. (The interior "RED" light popped on at the same time!)

Well guess what...it seems that base time in SH4 is at the International Date Line, just west of Midway Is. 180°. All other times must then be computed by the player as they make their way across the Pacific.

18:45 btw coincides with my TI-86(Starpath) ephemeris calc/nav pgm., for SS at my posit also. Don't know if you can see my relative bearing of the sun as he dips, but it's 144° that also coincides with 258° true, the actual azimuth of the setting sun on the RL nav pgm.

Scope: #1 aka Observation scope.
Mod: RFB 1.28

Originally Posted by don1reed

Here's an interesting pic of UL sun just dipping beneath the waves. My location: 28-15N 177-32W. What you see is the orange after-glow. The defined circumference of the sun has just disappeared.

Note the time: 18:45. (The interior "RED" light popped on at the same time!)

Well guess what...it seems that base time in SH4 is at the International Date Line, just west of Midway Is. 180°. All other times must then be computed by the player as they make their way across the Pacific.

I bet you started that mission at PEARL HARBOR, but used the "start out of harbor" option, witch puts you at 179.59.8 E or something like that - just outside MIDWAY. This would then corrospond with that BASE TIME is tied to what spot you start at. Now the question is if it counts the minutes as well....

My indications here - starting docked from PEAR HARBOR - is that BASE TIME is timezone X -10 with a 4 minute delay.

Ill try going across the pond taking SR and SS at each timezone center.

Remember the fast method.

Note the RedLight BaseTime for Sun Set.

Wait for nightfall and sighting of Polaris.

Measure Polaris altitude (Hs)

Hs - 1 = Lattitude of your boat. (roughly but better then just the Hs)

From the Lat. look up SunSet in Van's Almanac.

Basetime Sunset is converted to GMT (for Pearl Harbor thats timezone X to GMT)

Difference in sunset is found and substracted/or added to the middle of your local timezone(you know aproximately how far you have traveled with speed over time at course)

Now you can plot your position at SunSet and extrapolate it with speedovertimeatcourse to your present position. Now stick a new course if necesary to reach your goal.

Do that every morning and evening and you will be safe. In the morning its the reverse order of course. First the polaris fix then the sun rise time.