Real Navigation with SH4

[kv29]

So if the clock is ok, time measure should remain accurate for the rest of the mission, or the clock is bad too?

[Minimax]

So if the clock is ok, time measure should remain accurate for the rest of the mission?

Yes!

And we need the time difference (local time - GMT) for every start - location.

[kv29]

is there any way to mod the "timezone"?
we need an onscreen sextant mod!

[Minimax]

there is a sextant for SH3, but it doesn't work in SH4 - i do my best



SH3 Sextant: http://www.subsim.com/radioroom/show...eal+navigation


Edit:
@Mav87th
Sorry didn't read your postings completly

or if this corrosponds with my position lat/lng ?

YES!


Does the sh3 - sextant work for you?

Originally Posted by Minimax

And we need the time difference (local time - GMT) for every start - location.

So when one starts in PEARL one needs use PEARL time - TimeDif = GMT at all times while sailing...

Question is, will this be valid as well if one starts outside the harbor, or will it default to your homebase time there as well.....

[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

Note: reposted from SH3 Mod forum.

[don1reed]

@minimax:

You've made the same mistake as I have re sextant mod...

place the bottom of the sextant ( zero 0) on the bottom of the screen, not, I say again---NOT on the horizon. The sextant will not read low angle bodies & make sure the object you are observing is in the center of the screen, that is make sure you are view dead ahead, then press the (-) key to zero the screen. Do not elevate (up/down arrows), just rotate (left/right arrows) to the body of interest...get it centered in the screen. Bring the sextant from the side and maneuver it between the top/bottom of screen, (a small bit of yellow should be seen at top & bottom when properly adjusted. Registration marks). Now read altitude.

As I've requested and said elsewhere, the Observation scope would be a good candidate for substitute sextant, as it can be elevated to 90°; but, we need a way to read the elevation angle from horizon to body.

Minimax - how did you get that Sextant image to be draggable.....


And Don1 -- are you sure its not just course you started in the water west of Midway at campaign mission start... Witch would corrospond with Minimax's opinion about Base Time = time at start position in mission

[kv29]

I got confused

I calculated these 3 sunsets:

Pearl Harbor
Date: 07/10/44
157°59w 21°14N
sunset=18:24
SunAlmanac= shows a latitud of 10° at that hour. For 21°, sunset should be at 18:43
Starry night= visually shows sunset at 18:45

Brisbane
Date: 06/11/42
153°51E 27°9S
sunset=17:12
SunAlmanac=calculating time/degrees between 20° and 30° in SunAlmanac, you get exactly 17:12 :p
Starry night= visually shows sunset at 17:14

Perth
Date: 03/16/43
114°56e 32°11s
sunset=18:44
SunAlmanac=Shows a latitud of aprox 70° at that hour. For 32°, sunset should be at 18:16
Starry night= visually shows sunset at 18:18


wtf??

[Minimax]

@don1reed

place the bottom of the sextant ( zero 0) on the bottom of the screen,

Thanx for your explanation - my problem is:

Minimax - how did you get that Sextant image to be draggable.....

I don't get it draggable!


@kv29
Did you move your sub after starting the game?

I made some tests with the editor:
they're all like that:

******************
start position
40°00' S 140°00' W

sunset almanach:
19.32
sunset on-board-watch
19.32
******************

Same with in- and outside Pear Harbour: GMT sunset = local time sunset


I used that sunset almanac

http://www.vanjast.com/NavMod/RealNav_ReadMe2.zip

published by Vanjast here:

http://www.subsim.com/radioroom/show...eal+navigation