Celestia Forums

Hi,
I just downloaded Celestia, and what a great program!

One thing I lack (or haven't figured out how do to yet...) is the ability to position myself on the surface of a planet, say Earth, at a given longitude and latitude. There is not a "planetarium mode" where I can see and control the view in a topocentric-horizon coordinate system?

Anyway, it really looks great.

Hans.
hans@thejensens.dk

A quick way - go to any planet, find where you want to land, zoom in to about 3-5m.

More accurate - on the Navigation menu, choose Goto object. Type in desired planet, latitude and longitude, and distance. Click goto.
Hope this has been useful...

Even that, I'm facing the Earth. I need to turn around (how to turn exactly 180 degrees)? and stay with the Earth (how to do this? track object?).

If you use the arrows, you can rotate on your own 'axis', but it won't tell you how many degrees you've turned around. Celestia is more for space exploration. for what your trying to do, you should use stellarium or something like that.

You can use the Goto Surface command, CTRL+G in the Windows version, which places you in the surface on the actual latitude/longitude. It places you looking at the horizon (~90? turn). You can select whatever you want to see from the surface with the Select object command (or <Return> key and a bit of typing). Next, use 'C' to center the selection or 'T' to track/lock view on it.

I'd suggest you to open the Help/Controls popup to learn more. Look at the Celestia documentation too:

http://ennui.shatters.net/celestia/documentation.html

Thanks.

The "go to surface" command is good. Now I can see the night (and day) sky.

Still I think Celestia can be improved by adding a few commands to ease the use as a planetarium. What I hoped for is a simple way to go to a memorized location on Earth looking away from the Earth, and ways to point towards N/E/S/W/top (using the cursors or num pad, I can hardly tell which way I am looking at).

I understand that Celestia is not meant for a planetarium. Yet it seems all the difficult parts are already in place. Minor addtions will make it good for both purposes.

Also I hope to be able to directly enter a value for FOV, instead of shift-drag.

Are you aware of the alt-azimuth controls described in this thread: http://shatters.net/forum/viewtopic.php?t=2381?
Might help a little.

Grant

After reading the thread, I tried control-F and Celetia replies "alt-azimuth mode". I didn't notice any difference in her behaviour. Nor did I find a "non-alt-azimuth" mode to revert back to.

What is the mode doing, and how can it help me to find N-E-S-W?

(these commands all assume you're using Windows)

1) use the "Goto Object" menu and go to a particular lat,long of the Earth (e.g. 51.47722, 0.0 -- the location of Greenwich, England)

2) use the "set time" menu and go to a time at night (e.g. 00:00:00 UT)

3) type the "Ctrl-G" key combination to land on the surface (e.g. if you have the "Night Side Lights" turned on, you'll be surrounded by the bright lights of the city, but the sky above you will be dark. Make sure you have the clouds turned off!)

4) type the "Ctrl-F" key combination to turn on Alt-Azimuth mode

5) You now can use the left and right arrow keys to turn around: "Ctrl-F" has made it so the horizon will stay level.

6) type the ";" key to turn on "Celestial coordinates". You'll see gridlines appear on the sky. this is just to help you stay oriented.

7) type "Ctrl-M", "Polaris", "Ctrl-M" (or use the "Return" key instead of "Ctrl-M". Don't type the quotes or commas) to select Polaris -- the star closest to the north pole on the sky.

8) type the letter "c" to center Polaris

9) use the "up arrow" key to look back down toward the horizon. You are now facing north.

10) take a note of how the RA and Dec lines are oriented.

Does this help?