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Thread - Seeing Stars with Celestia

On 17/1/2003 Ian Musgrave posted:

I've been playing with a program called Celestia, a FREE Solar System simulator that is absolutely mind-blowing.

I've ridden on Galileo, watched sunrise on Upsion Andromedae d and zoomed past Eros and comet Borrelly.

This is relevant to us because not only is it a great toy, but it is also Astronomically accurate, so it is great for teaching
(see the lesson plan at the shatters site for an actual example), and following current astronomical events.

I plan to use it as an adjunct to my skywatch site to illustrate some aspects of astronomy.

If anyone is interested, there are warnings

1.  It is a honking big program, around 10 Megs (!!!), so it will take a while to download (and takes up a chunk of disk space)
2. The latest version (1.2.5) has a conflict with Microsofts OpenGL graphics drivers V1.1, which is the bog-standard OpenGL driver on Win 98, Win 2000, Win XP and WinNT 4.0 systems. So if you have a bog standard installation, or don't know what your open GL driver is download the 1.2.4 version at the second URL (so you don't spend hours downloading to have the program crash on you).
3. It is a resource hog, so it should be the only program running when you run it.

As an example of what's possible here are two files that you can play with (this works in both 1.2.5 and 1.2.4).

The close approach of 2002 MN to Earth on Jun 14 2002, clip and save mn.cel in this message to the main directory as a
plain file (watch out for microsofts tendency to attach a .txt extension to everything).

Then either download neo.ssc from the celestia site to extras, or clip and save mn.ssc to extras. Open Celetia after this (or close and re-open it), Choose File | Open Script, then chose mn.cel and enjoy.

===========snip and save as mn.ssc in extras====================
"2002 MN" "Sol"
{
         Class "asteroid"
         Mesh "asteroid.cms"
         Texture "asteroid.jpg"
         Radius 0.05

         EllipticalOrbit
         {
         Period            2.570451729
         SemiMajorAxis     1.8764616
         Eccentricity      0.5107689
         Inclination       0.11721
         AscendingNode   103.60017
         ArgOfPericenter 115.02029
         MeanAnomaly     358.20808
         Epoch       2452400.5
         }

         RotationPeriod   30.0
         Albedo            0.1
}
============================8<===============8<===================

============snip and save as mn.cel in Clestia directory =============
{
         # 2002 MN close approach to Earth 14 June 2002
         # needs some work on correct orientation
         time { jd 2452439.5 }
         # 14 June 2002 in Julian Days
         select { object "Sol/2002 MN" }
         # Select our asteroid
         follow {}
         # Self evident really
         goto { time 5 }
         gotolonglat { time 0 distance 5 longitude 270 latitude 30 }
         # Position ourselves above the asteroid so we can see the Earth
         timerate { rate 1000 }
         # Speed everything up 1000x
         wait {duration 5}
         orbit { axis [ 1 0 0 ] rate 5 duration 25 }
         # Orbit the asteroid so the we can watch the Earth whiz by
         # this is a bit jerky