Yep, another sunrise/sunset topic.

Von Due · 07-31-12, 08:01 AM

After searching the forums and getting the moon/sun table I am still wondering how this works in SH3.

For one, the game world is flat and rectangular but still I am going with the degree marks on the nav map trying to figure out how to come to agreement with the rest of my crew when the sun sets and rises. I am using the interior light switch as indicator.

Testing, I sailed off to E 0* 0' N 60* 0', got there 3. August 1939. Submerged in time to position myself within no more than 5 metres from the actual spot.

3. Aug. Sunset 2117 GMT
4. Aug. Sunset 2108 GMT

7 minutes difference.

I understand how the sunset hour changes as the days go by but 7 minutes from one day to the next seems a bit much. Is the switching to night lighting a good enough indicator or should I have watched the sun set myself?

Digression:
The next sunrise, Immediately after the lights went to day lighting, I got the true bearing to where the sun rose. It was close to 54*
At 1200 GMT I noted the sun's true bearing at about 166*
In a whim, I looked at these angles:
90* - 54* = 36*
180* - 166 = 24*

36* + 24* = 60* which happened to be my latitude. Question that needs answering is whether this was a coincidence or not. The thought is that the true bearing will be offset from due east the further away from the Equatoral line I get. I want to see how much that offset is at various latitudes. The offset from due south at noon is more puzzling. I haven't got a clear idea what's causing that.

Sailor Steve · 07-31-12, 09:00 AM

I can't answer for bearings, but a quick look at an almanac for any year and any place reveals that sunset time changes by about one minute in the month of August, so you're right to question the in-game sunset times.

Pisces · 07-31-12, 09:21 AM

The light in the game flips when the sun is halfway on the horizon. Yet RL sunset/-rise calculations are based on the full disk being obscured, or the upper edge being on the horizon. So you have to take that time difference into account.

Von Due · 07-31-12, 09:49 AM

Thanks to both of you. It seems to me the game world is a bizarre mix of spherical geometry applied to a flat world. It's a challenge making head and tail of the observations. I remember getting headaches years ago when I last played SH3 trying to figure out the timetable. I feel that headache is returning

Basically, what I have been assuming so far is that, in the game, at a given latitude, the sunrise/sunset would happen at the same hour local time every 15 degrees longitude. I'm more than ready to challenge that assumption but I will carry on testing, getting the sunset hour at N 50* and N 60* at W 0* and W 15* (which would be centre of that time zone I assume).

The light switch before actual sunset is precicely the sort of info I needed. Now I know the switch master can't be trusted and I will watch the sun myself, if possible. I could need an Always Clear Skies mod for that

Pisces · 07-31-12, 01:44 PM

Also, iirc there was something funny with where the game considers the timezones to end. Like GMT (or UT) is valid within 7.5 degrees on either side of the Greenwich Meridian line. Whereas in RL the timezone exists only 15 degrees on the west side of the Greenwich Meridian.

And then iirc there was also mention in one of the old Celestial navigation threads of local time or base time not being correctly displayed for the local timezone after a savegame reload. I never noticed this myself. But something you might want to keep an eye on and do some investigating.

Von Due · 07-31-12, 02:35 PM

Greatly appreciated info there, Pisces.

EDIT: Just a short report

8. Aug 1939

W 15* 0' N 75* 0'

Tracked the sun at 0000 local time, again at 0100 and last at 0300.

At 0000 the sun was at true bearing 346.5
Lowest height above horizon at just before 0100 due north.
True bearing at 0300 was 30*

It adds up neatly that in 3 hours, the sun moves 14.5* pr hour, given errors in measurements and eyeballing.

The sun at the lowest at 0100 local time (ship time 0200) on the other hand gives me more to ponder.

Right now I'm considering Earth to be cylinder shaped but who knows.

Gargamel · 07-31-12, 05:10 PM

As Pisces said, the game bases day/night from where you loaded. So when load in port, the time is accurate to the exact local, not your timezone. As you move through the game world, the clock is not adjusted, nor does the sun alter it's path (based on whatever the game engine works off of, as you are finding out).

When you load a game from a save mid patrol, the clock is saved and loaded without change, but the game adjusts sunrise/sunset as if the ships clock is now the local time. So during operations off the America's, or on a trip to the pacific, you could save in middle of the night, but load during the day, without the clock moving.

Not sure if this helps in your calculations, but it is something to consider.

07-31-12, 08:01 AM	#1
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	Yep, another sunrise/sunset topic. After searching the forums and getting the moon/sun table I am still wondering how this works in SH3. For one, the game world is flat and rectangular but still I am going with the degree marks on the nav map trying to figure out how to come to agreement with the rest of my crew when the sun sets and rises. I am using the interior light switch as indicator. Testing, I sailed off to E 0* 0' N 60* 0', got there 3. August 1939. Submerged in time to position myself within no more than 5 metres from the actual spot. 3. Aug. Sunset 2117 GMT 4. Aug. Sunset 2108 GMT 7 minutes difference. I understand how the sunset hour changes as the days go by but 7 minutes from one day to the next seems a bit much. Is the switching to night lighting a good enough indicator or should I have watched the sun set myself? Digression: The next sunrise, Immediately after the lights went to day lighting, I got the true bearing to where the sun rose. It was close to 54* At 1200 GMT I noted the sun's true bearing at about 166* In a whim, I looked at these angles: 90* - 54* = 36* 180* - 166 = 24* 36* + 24* = 60* which happened to be my latitude. Question that needs answering is whether this was a coincidence or not. The thought is that the true bearing will be offset from due east the further away from the Equatoral line I get. I want to see how much that offset is at various latitudes. The offset from due south at noon is more puzzling. I haven't got a clear idea what's causing that. Last edited by Von Due; 07-31-12 at 08:13 AM.

07-31-12, 09:00 AM	#2
Sailor Steve Eternal Patrol Join Date: Nov 2002 Location: High in the mountains of Utah Posts: 50,369 Downloads: 745 Uploads: 249	I can't answer for bearings, but a quick look at an almanac for any year and any place reveals that sunset time changes by about one minute in the month of August, so you're right to question the in-game sunset times. __________________ “Never do anything you can't take back.” —Rocky Russo

07-31-12, 09:21 AM	#3
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	The light in the game flips when the sun is halfway on the horizon. Yet RL sunset/-rise calculations are based on the full disk being obscured, or the upper edge being on the horizon. So you have to take that time difference into account. __________________ My site downloads: https://ricojansen.nl/downloads

07-31-12, 01:44 PM	#5
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	Also, iirc there was something funny with where the game considers the timezones to end. Like GMT (or UT) is valid within 7.5 degrees on either side of the Greenwich Meridian line. Whereas in RL the timezone exists only 15 degrees on the west side of the Greenwich Meridian. And then iirc there was also mention in one of the old Celestial navigation threads of local time or base time not being correctly displayed for the local timezone after a savegame reload. I never noticed this myself. But something you might want to keep an eye on and do some investigating. __________________ My site downloads: https://ricojansen.nl/downloads

07-31-12, 02:35 PM	#6
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	Greatly appreciated info there, Pisces. EDIT: Just a short report 8. Aug 1939 W 15* 0' N 75* 0' Tracked the sun at 0000 local time, again at 0100 and last at 0300. At 0000 the sun was at true bearing 346.5 Lowest height above horizon at just before 0100 due north. True bearing at 0300 was 30* It adds up neatly that in 3 hours, the sun moves 14.5* pr hour, given errors in measurements and eyeballing. The sun at the lowest at 0100 local time (ship time 0200) on the other hand gives me more to ponder. Right now I'm considering Earth to be cylinder shaped but who knows. Last edited by Von Due; 07-31-12 at 04:44 PM.

07-31-12, 09:49 AM	#4
Von Due Sea Lord Join Date: Jul 2012 Posts: 1,690 Downloads: 30 Uploads: 0	Thanks to both of you. It seems to me the game world is a bizarre mix of spherical geometry applied to a flat world. It's a challenge making head and tail of the observations. I remember getting headaches years ago when I last played SH3 trying to figure out the timetable. I feel that headache is returning Basically, what I have been assuming so far is that, in the game, at a given latitude, the sunrise/sunset would happen at the same hour local time every 15 degrees longitude. I'm more than ready to challenge that assumption but I will carry on testing, getting the sunset hour at N 50* and N 60* at W 0* and W 15* (which would be centre of that time zone I assume). The light switch before actual sunset is precicely the sort of info I needed. Now I know the switch master can't be trusted and I will watch the sun myself, if possible. I could need an Always Clear Skies mod for that

07-31-12, 05:10 PM	#7
Gargamel Lucky Sailor Join Date: Oct 2010 Location: Rome Posts: 4,273 Downloads: 81 Uploads: 0	As Pisces said, the game bases day/night from where you loaded. So when load in port, the time is accurate to the exact local, not your timezone. As you move through the game world, the clock is not adjusted, nor does the sun alter it's path (based on whatever the game engine works off of, as you are finding out). When you load a game from a save mid patrol, the clock is saved and loaded without change, but the game adjusts sunrise/sunset as if the ships clock is now the local time. So during operations off the America's, or on a trip to the pacific, you could save in middle of the night, but load during the day, without the clock moving. Not sure if this helps in your calculations, but it is something to consider. __________________ Luck is a residue of Design.