SH4 vs the real sky

[Rockin Robbins]

You've seen the sky in Silent Hunter 4. We have guys doing celestial navigation while playing the game using an astronomy program for star positions.

Let's put you on the deck of a submarine off the coast of Florida just about now at 9:30 PM or so local time (Zulu -4). Now I want you to look north, point your cell phone camera up about 40º and take a photo as I have.

And here's my new cell phone photo from last night of the Cassiopeia area. (don't try this with your new iPhone. It can't cut the cheeze) Can you find the constellation Cassiopeia in this Milky Way mess of stars? How about Cepheus? The stars in the top of the Northern Cross of Cygnus?

This is a fricking huge area of sky (field is over 70º wide!) from the top of Cygnus at upper left to Cepheus, Cassiopeia, a chunk of Perseus...yikes! Imagine seeing this with your naked eye. You could from the deck of a submarine in the Pacific ocean. It's tough to navigate while you are freaking out from all these stars.

Our vantage point is about 3/5 of the way out from the center of the galaxy, looking outward at the galactic disk between us and intergalactic space outside the rim of our galaxy. This is the direction that we see the fewest stars. Wait until I can take a picture toward the CENTER of our galaxy and we'll see how good you are at picking out constellations then.

[cloadmcally]

Well RR, I agree with you but sh4 is a simulative videogame, and beeing a simulator means that it tries to reproduce reality as realisticly as possible, and while I think that it would be a really cool mod, I'm afraid the game might explode, maybe I'm wrong though!
Anyways it's a good thing that you brought up this topic, we could really discuss a lot of things with that base!
Cload

[Captain Dave]

I always did think the developers skimped on the stars in SH4. I'd like to see 10 times more, but haven't tried to increase them yet. I'm still trying to get rid of a blotchy sky at night.

[Rockin Robbins]

One problem is that with the resolution available to them it is absolutely impossible to do justice to the subject. My original photo is 5312x2988 resolution. They were working with 1024x768 or not much better.

I just thought it would be fun to show what the sky really looks like. Many have never seen it. Even photographers take photos of tiny parts of the sky. This is 70º wide of stuff the naked eye could see if....

The best way to explain it is that your fist is 10º wide at arm's length. This is seven fists wide in the sky--a major swath.

[Captain Dave]

Camping in the mountains of Utah, I always liked watching all the satellites and shooting stars. Even seeing the cloud of stars in the Milky Way arm was amazing.

[Rockin Robbins]

Okay here's a side by side, actually one above the other comparison. The view from the bridge is not as wide as the field of view in my cell phone so they are not identical in field. I did put Cassiopeia in the upper left corner of both shots.




Becha can't guess which is which!

[cloadmcally]

holy moly that's pretty embarassing hahaha
ok, we NEED a new night sky mod!
Any ideas RR? seems like you can do mods for everything

[Rockin Robbins]

I haven't messed with the sky for the same reason I haven't messed with environment, inappropriate planes and all that other eye candy. If you're fighting your sub, you aren't caring too much about the water color/transparency/floaty stuff or counting stars or wondering why that Zero is dropping bombs. You're submerged, avoiding these things.

Suppose we added a couple hundred stars to that field of view. That would still be less than half the stars in my photo and what would be the cost in game lag?

"You CAN'T press that button, I have to compute positions for 500 stars every five seconds." I think the cost wouldn't be worth the gain.

Maybe the next generation of computers will be good enough. Then the limiting factor will be the drink coaster model of game production. Game companies get one blast of income from a game and it's all over. We might play the game for ten years, but they're outta there in six months.

[Armistead]

Just amazed the got the moon phases correct, even most eclipses are close in the game timed correctly with textures overlapping or touching..

[Rockin Robbins]

What I've seen is moon phases NOT correct at all. I remember one screenshot of the full moon sitting beside the sun and everyone remarking how accurate it was.

Well it might be accurate if you can find what source of light is illuminating the full moon, since the sun is BEHIND IT!!!! And why is the moon 4 times its actual size?

Moon phase is hard-linked between moon phase, moon rise and set times (the full moon NEVER CAN rise at midnight, for instance) and angle betweein the Sun and Moon. Change one of them (or change the size of moon and sun and all eclipses are laughable) and you have what we have in Silent Hunter 4: astronomical farce.

SH4 is not an astronomy simulator. Not even close. That is especially true for solar system astronomy.

[aanker]

I've found that by adding or subtracting hours to my 'ships clock' (which is using base time ) depending on my distance from base, the tables available on the internet for Sunrise & Sunset, Moonrise & Moonset, and the Moon phases are very close to what I see in SH4.

Unlike real life, Latitude doesn't seem to be factored in, but longitude is, which is why knowing what time it is where I am is useful; base time + 5 hours for example.

This information is so helpful that I added the tables for the Sun & Moon and the moon phases to my in-game F1 Help file, for use in planning my attacks, recons, whatever.

I begin each patrol by drawing vertical lines for each time zone on my chart. No, I don't include the jogs that some real time zones have, but I start at the 180d date line which is in the center of its time zone, draw two lines on each side 7.5d to the East and West, then every 15d from those lines. Each of those lines is one hour.

I made this into a mod for a friend years ago. Editing the in-game F1 Help file to include useful information is helpful : ) Ha!

Happy Hunting!

[Rockin Robbins]

Surely you know that sunrise and sunset change with longitude as well as latitude and the game makes no allowance for that? SH4 thinks we live on the outside of a huge toilet paper roll.

[Rockin Robbins]

Let's put it this way. Here is Kim Ronoff screenshot from Dutch Harbor, Alaska on a certain date. See the crescent moon actually in contact with the sun? Isn't that just a freakin' impossibility!



Kim entitled this an Alaska eclipse. But much is wrong with this picture. First is the relative sizes of the moon and the sun. In the real world the sun and moon are almost the same size, half a degree in angular size. Because their distances from Earth vary because of the shape of the Earth's orbit around the sun and the shape of the moon's orbit around the earth, their sizes vary a bit.

Sometimes the moon is a tiny bit larger than the sun. Sometimes it is a tiny bit smaller than the sun. BUT IN NO CASE IS ONE TWICE THE SIZE OF THE OTHER! Here the moon (over twice its real size in the sky) is dwarfed by a huge sun which is over four times larger than it is in the real sky. MONSTROUS FAIL.

Then we look at the bodies themselves. The sun shines by its own light so is always full and by some stroke of coincidence the game shows it that way also.

But the phase of the moon is determined by the only source of light to illuminate it: the SUN. So if the moon is so close to the sun that it is touching and the only possible source of illumination IS the sun, what phase is it? That's right boys and girls, the sun would illuminate the side away from us and we wouldn't see the moon AT ALL!

That's what a lunar eclipse is. The moon, backside light, passes directly in front of the sun during the daytime and we see a black moon covering the face of the sun, obscuring some of the light. If the moon is exactly aligned with the Sun, we could have a total eclipse, where the sun vanishes and the moon is not seen because its lighted side is on the back side where we can't see it. Or if we're in a time where the moon is slightly smaller than the sun we'll see a circle of black in the middle of the sun with a thin ring of bright light from the sun around it. That's called an annular eclipse.

Now that we've thoroughly trashed the screenshot beyond all recognition, let's take a look at the output from a piece of astronomical software called Cartes du Ciel to see what the sky really looked like at the time. Is there ANYTHING valid going on here at all?



Here's the same date as Kim's screenshot from Dutch Harbor. Now I don't know in his screenshot exactly what the sun's position is on the horizon so we can't check that. I don't know the game time so we can't check that. So I just picked the time when the sun was halfway risen to check relative position of the moon. The moon is not visible because it is zero percent illuminated from the earth, but it is there, above and to the left of the sun.

Now at first glance it appears that Kim's screenshot shows an eclipse and at that time there was no eclipse. But you have to remember that SH4 shows the sun at 4 times actual size and the moon double its true size. That means that when they're close together SH4 will show the eclipse when there was no eclipse at that time of the morning.

Now lets look at an animation of the actual eclipse of that day on the same horizon plot as before. There WAS an eclipse that didn't happen until about noon. Lots of cool stuff going on here. First of all, when you look at the shot in the morining you say "look at the sun. It's rising!" But it isn't at all. In fact it's moving much more left to right than it is rising. As a matter of fact it (and the moon) are flying in formation almost horizontally ACROSS THE SKY! So this is a time lapse view of their flight across your sky, Dutch Harbor, Alaska, February 4, 1943. Enjoy.



Remember what I said that sometimes the moon is smaller than the sun? That was true this day, February 4, 1943. And you can see that although the moon passes completely in front of the sun, there is still a ring of sunlight around the outside of the moon at full eclipse.

So the only information that SH4 provides that is correct is the positions of the center of the sun and moon. The phase of the moon is wrong, the sizes of both are wrong. If there is an eclipse all timings are wrong and there will be several times more eclipses in SH4 than in real life.

I have made no attempt to figure out whether planetary positions are right in SH4. SH4 isn't an astronomy simulator and it's not fair to judge it by its astronomical accuracy.

[aanker]

Originally Posted by Rockin Robbins

Surely you know that sunrise and sunset change with longitude as well as latitude and the game makes no allowance for that? SH4 thinks we live on the outside of a huge toilet paper roll.

Yes, I realize this and said, "Unlike real life, Latitude doesn't seem to be factored in, but longitude is..."

On that giant sheet of paper that is the SH4 chart, East and West of 180d does matter. Furthermore, the sunrise/sunset local times will change, and are very close to the published times.

Check it out in-game : )

[Rockin Robbins]

You got it backwards. Longitude matters, latitude doesn't in the game. Edit: I got it confused and just copied what you said. I'ma goina crazy there...... But yes, I'll check out some setups and post them to see what's accurate and what is not.

Wouldn't you love to visit Alaska and actually watch the sun fly horizontally across the sky? Now THAT would be amazing to watch.