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Error in solarsys.ssc Mercury definition
Posted: 03.12.2002, 00:55
by granthutchison
There's a typo in the solarsys.ssc definition of Mercury. It should read
not
1047.509. The correct setting maintains the 2/3 spin/orbit resonance, and allows you to watch the Sun moving backwards at noon when Mercury is at perihelion.
Grant
Posted: 03.12.2002, 01:09
by Calculus
I actually tried to watch the sun moving backwards but it didn't work.
Now I know why
Thanks again Grant
Correct Mercury orientation
Posted: 03.12.2002, 01:20
by granthutchison
If you would like to get Mercury correctly orientated, too, use the following
Code: Select all
RotationPeriod 1407.509405
Obliquity 7.01
EquatorAscendingNode 48.42
RotationOffset 291.20
(There's a 180-degree error in the EquatorAscendingNode in the original.)
The RotationOffset is correct for a texture map with a central meridian of zero degrees. It brings the zero and 180 degree meridians to their correct positions at the "hot poles" - the two areas that get local noon at perihelion.
Grant
Posted: 03.12.2002, 03:44
by chris
Calculus wrote:I actually tried to watch the sun moving backwards but it didn't work.
Now I know why
Thanks again Grant
Aha! I'd been wondering about this too . . . Now I'm finally able to see the double sunrise!
--Chris
Posted: 03.12.2002, 04:12
by billybob884
so how do you view this "double sunrise"?
Posted: 03.12.2002, 13:56
by granthutchison
billybob884 wrote:so how do you view this "double sunrise"?
Having pasted in the new definition for Mercury that I posted, go to latitude 0, longitude 90 on Mercury, 0.002km above the surface. Track Sol, and speed things up a bit. You should see the Sun getting gradually bigger as it drops towards the horizon, setting by a tad more than half its width and then popping back up again. Repeat performance at sunrise - up, down, up.
Nice test that I've got all the numbers right, since that effect should only be visible on the horizon at 90 degrees and 270 degrees longitude.
Grant
Posted: 03.12.2002, 18:54
by Calculus
I made screenshots of a sunset on mercury.
Have a look at my gallery.
Posted: 03.12.2002, 19:36
by chris
Calculus wrote:I made screenshots of a sunset on mercury.
Have a look at my gallery.
That's a great image! I've never the Sun's path through the sky illustrated so well. So how do you create your 'strobe' images?
--Chris
Posted: 05.12.2002, 01:23
by Calculus
That's a great image! I've never the Sun's path through the sky illustrated so well. So how do you create your 'strobe' images?
--Chris
Thanks Chris
I actually make several captures and assemble them. In this particular example, I also removed the sun flare to get a clear effect.