View Full Version : Sunrise/sunset times
I remember back in the original SH1 there was a way to get sunrise/sunset and moonrise/moonset times as well as the current phase of the moon. I *think* it was on the wall calendar in the captain's cabin IIRC, but it's been years since I played it. Is there an equivalent to this in SH4 1.5 with TMO 2.0?
So far the SH4 astronomers have not been able to find a predictable pattern in the phases of the moon. People her have shown screendumps of the moon to be near the sun, yet showing a first or last quarter moon. So that one is out. Maybe it's rising and setting is accurate in the game. Never checked that really.
Sun rise and set is accurate to the time and place. But you need to know where you are to be able to calculate the right clock time. There are threads about celestial navigation where it is discussed extensively. Don't have the link ready though. Just search for celestial navigation in the SH4 (and sh3) forums.
There isn't anything similar as SH1, that I'm sure, for any stock/supermod flavour.
Armistead
09-09-10, 08:16 AM
As stated, I've seen SS with the moon and sun almost on top of each other on the horizon.
One thing that is right, in the winter time in the North Pole it stayed dark almost all day when I checked out the ice shelf.
As stated, I've seen SS with the moon and sun almost on top of each other on the horizon.
...Well, that's not unheard of. The question is if that would have been a (near) solar eclipse in real life too at that very same day any time (and place).
Armistead
09-09-10, 09:53 AM
Not my field, but never heard of a eclispe on the horizon.
Deephunter
09-11-10, 02:07 PM
Solar eclipses can be seen at just about any point in the sky, depending on where you are when they occur. The moon would not be visible in close proximity to the sun as the sunlight would be greater than the moon's reflected glare.
I was lucky to witness a total eclipse of the sun waaayy baaackkkkk in 1991. That is one experience I won't ever forget. "Totally" awesome....
Rockin Robbins
09-11-10, 08:36 PM
Solar eclipses can be seen at just about any point in the sky, depending on where you are when they occur. The moon would not be visible in close proximity to the sun as the sunlight would be greater than the moon's reflected glare.
I was lucky to witness a total eclipse of the sun waaayy baaackkkkk in 1991. That is one experience I won't ever forget. "Totally" awesome....
Actually a solar eclipse can only happen at the precise instant of the new moon because that is when the moon is closest to alignment with the sun. If you see a total solar eclipse, then, it will happen at high noon local time. This can be any time by your clock between about 11:00 am and 1:00 pm depending on how close to the center of your time zone you live. At the equator, the path of the total eclipse moves at 1000 miles per hour across the face of the Earth.
You can see a partial eclipse any time between sunrise and sunset.
Also, you do not see the moon because there is no reflected light from the moon during an eclipse. Only the half facing away from you is lit and no portion of the lighted part of the moon can be seen. During the eclipse you will see the moon lit dimly by earthlight, the reflected light off the earth bouncing back to the dark side of the moon.
Armistead
09-11-10, 09:33 PM
The old man I use to work with years ago was a hoot. If you asked him what the sun was, it was a sun. Could never convince him it was a star, it was a sun, after all star are little white dots and far away. Even when I showed him in a science book...no go.
I've seen weird things too like the sun in front of the moon but that is an artifact from how the sky is rendered by SH4
Regarding times:
Out of Pearl for example I always draw lines 7 1/2 degrees each side of 180d - IDL - then go 15 degrees west from there ( & east to Pearl) for each hour and the sunrise sunset times are pretty close: from SJ it is roughly 4 hours from base time, from the Yellow Sea 5 hours etc.
Furthermore the moon phases, moon rise, and moon set are also close to my tables.
I made 3 pages of my help file into tables; moon rise, moon set, sun rise, sun set, and the phases for use while I'm on patrol. SH4 is close enough for me.
Happy Hunting!
Art
Rockin Robbins
09-13-10, 12:37 PM
Holy Cow Aanker, that's ludicrous!
http://i196.photobucket.com/albums/aa293/RockinRobbins13/Silent%20Hunter%204/KimRonhoffAlaskaeclipse.jpg
Here is the ridiculous shot from Dutch Harbor that started my whole investigation. Here we have a crescent moon in contact with the setting sun in the sky. There are many, many problems with this rendering.
Perfectly obvious is that the moon is rendered half or maybe even a third the size of the sun. That is completely false. They are both almost exactly the same size in the sky due to an amazing coincidence. In reality the sun is almost exactly 100 times larger in diameter than the moon. But its distance is also almost exactly 100 times further, making them look identical sizes in our sky, not one three times larger than the other as rendered by the "close enough for me" SH4. Because of the non-circular orbit of the moon it gets much less than a tenth of a degree larger or smaller than its nominal half degree size. The earth's orbit around the Sun is nearly but not perfectly circular, so the sun also changes a tiny amount in size depending on when you look at it. We're talking about tiny, tiny differences, never even detectable unless during an eclipse. For all normal purposes, they are identical in size, subtending almost exactly one half a degree in angular size. In this regard, SH4 can't be called "close" unless you are laughing while doing so.
The second error in the screenie is the phase of the moon, which leads to the third error, the setting time. Most people don't realize that the phase of the moon directly tells you its setting time! For instance, a 3/4 moon (that's half lit) is always straight overhead at sunset. Since it is straight overhead at 6 pm astronomical time, that means it is three hours behind the sun and can't set until 9 pm. The moon in the screenie is about 1/8 phase. That means that its position is wrong and should be rendered a quarter of the way between the zenith and the sun. That is the ONLY position where the moon can show that phase. This would shift the setting time to 1/8 of the 12 hour daylight period or one and a half hours later than SH4 will show it. Is an error of an hour and a half "close?"
If you want to chase the rabbit of "the moon is rendered in the right place and the setting time is accurate" then you have forced SH4 into another error of showing the moon at completely the wrong phase. At that position the moon would be new, with no lighted portion visible at all. You would be totally unaware that the moon was in the sky without an almanac or having followed it from previous days when it was visible.
I haven't even barked up the tree that the original poster told me the date represented and that it was the date of the animation I have already posted in this thread. Since it was the day of the eclipse, we know the alignment of moon and sun. At sunset it would have been after the eclipse and the moon would have been invisible, but to the right of the sun, not above it and slightly to the left.
So SH4 doesn't get close in any aspect of the screenshot. Fail, fail, fail, fail. In what way can that be "close enough" unless you just don't care when the setting times are, what size the bodies are, where they are depicted in the sky and what phase is shown?
Silent Hunter 4 is not a solar system simulator and wasn't ever meant to be. Trying to hold it to that standard is ridiculous. We see a sky. That is about as far as it goes.
Holy Cow Aanker, that's ludicrous!
Huh?
The first thing I wrote was:
I've seen weird things too like the sun in front of the moon but that is an artifact from how the sky is rendered by SH4
Next I described how to get pretty close sunrise sunset times. SH4 as a game gets them close enough for me: every 15 degrees = 1 hour from base time ( East <---> West from Pearl). I didn't mention Dutch Harbor. I didn't call SH4 a solar system simulator. I didn't compare the size of the sun & moon.
I did mention the moon phases in SH4; the phases and moonrise, moonset are all close enough for me.
The OP missed the calendar that SH1 had. So do I. SH1 was not an astronomy program either but knowing when it would be dark for example, would help in planning an attack - like a night surface attack or a night periscope attack. Knowing when the moon is not up at night is useful. SH4 gets that close enough for me.
I was trying to help the OP make sense of what SH4 does provide.
Holy Cow Robbins, relax!
Happy Hunting!
Art
Rockin Robbins
09-13-10, 08:49 PM
Sorry, it's the amateur astronomer in me getting the best of my judgment. Yes, it is helpful to have a table of how the game treats sun and moonrise times, whether they are right or wrong. You are completely right about that point.:salute:
Sammi79
09-18-10, 01:21 PM
How much work would it be to create an SH4 almanac? I'm assuming a very large amount of time and effort. That would be perfect though to have charts that correctly stated the various (incorrect) positions of celestial objects as rendered in SH4. It is easy to change the relative sizes of the sun and moon so that they are the same, aswell as the correct relative size in degrees, I don't know how to alter phases atm but that would be all you'd need for realistic navigation. I personally wouldn't know where to start on such an ambitious project, but I'd be willing to help out if someone started it off. That would absolutely complete the game for me, anyway. I could never get on with using external programs to render the night sky to do nav calculations.
The almanac has already been made. I extracted 3 pages and added them to my F1 help file from:
http://www.subsim.com/radioroom/showthread.php?t=138585 - the Combat Information Center mod and I find it very useful. The full moon and new moon phases, moonrise moonset times seem to be pretty close as well as sunrise sunset times but I don't want to get jumped on for saying that. They are close enough for me considering this is a game.
This same information is available from NASA and maybe it is in other mods.
You sound very ambitious if you really want to fix the SH4 sky for navigation - if it is even possible(??). Good luck if you do!
Happy Hunting!
Art
Rockin Robbins
09-18-10, 06:40 PM
The stuff is all hard-coded. You can mess with the way things are displayed, but not what and where it is displayed.
Personally, I'm in aanker's corner. This isn't a solar system simulator and what we got is pretty impressive considering that it is just meaningless window dressing on the game.
Sunrise, sunset, noon times for each day? No submarine would have been without them! By comparing the difference between your sunrise and the GMT sunrise you directly work out your longitude without a lot of hocus pocus. That information was indispensable for the real sub jockeys. SH1 had it right. SH4 missed by a mile there.
Oh, I forgot. I was supposed to jump. Darn. Missed it by that much...
When I'm in the mood I keep a rough record of sun(moon)rise/sun(moon)set and moon phases as I cruise towards my objective. An in-game "almanac" is certainly a "must" have.
.
Sammi79
09-19-10, 04:59 AM
The stuff is all hard-coded. You can mess with the way things are displayed, but not what and where it is displayed.
Personally, I'm in aanker's corner. This isn't a solar system simulator and what we got is pretty impressive considering that it is just meaningless window dressing on the game.
I might be a bit off track here but it seems what we need is a record of where and when the sun, moon and (specific) stars are displayed in game, as opposed to reality. Also we need to know what (if any) solar cycles for the rendered sky objects are modelled I.e the tilt of the earths axis relative to the sun over the year, refraction and height of eye, Are the celestial poles in the correct places in the sky etc... As I would assume that many of the intricacies of the reality are not modelled, plenty of the more difficult navigational calculations and adjustments would not be required, still it would be very entertaining to be able to measure in game objects and come to an acceptably accurate plot of your current in game position.
I have Dl'd the real nav mod pack and poked around a lot and there are obviously severe limits for measuring tools due mainly to the scale of the in game display. Any pseudo sextant graphic is dependant on a) resolution and b) FOV settings in cameras.dat Using the Obs scope is a good idea but with no way to attach a vertical vernier scale it serves only to further limit the altitude that celestial objects can be measured.
Damn I'm getting that 'must go and have another look in those files' feeling :damn:
WernherVonTrapp
09-22-10, 04:22 PM
Just in case a reference is needed:
http://eclipse.gsfc.nasa.gov/phase/phases1901.html
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