Celestia Forums

I would have expected to find an answer to this question via seraches but no such luck... sorry if this quiestion is already answered, I tried to look.

I am not very good at celestia and I really only use it to illustrate fictional star systems. I only know the basic terms illustrated in some tutorials and don't know much about astronomy, physics or mathematics. Could anybody tell me in simple terms how to tidally lock a planet? I set the inclination to 90 degrees but I still have to get one pole somehow following the star.

Oh, also I'm not really fussed which pole ends up at the night-side or day-side because it's a barren rocky planet.

The easiest way is to do nothing: delete all rotational specifications from the SSC file.
Tidal locking is the default.

Here's an example. The long axis of the planet "locked" always points toward the Sun.

Ok thanks it worked to take out all rotational details.

I use a different layout for my code than you do:



What does yours mean? Also is there a way to get my locked planet to still spin, but on its side so that one pole always faces the star?

Your SSC looks fine.

I used SemiAxes so I could quickly verify that it stayed pointing in the right direction. With one dimension so much bigger than the others, it makes the planet look like a spear. I didn't feel like using a texture, and Coloring it green made it more interesting than plain white.

I think what you describe probably could be done with two coordinate systems -- an invisbile "parent" and the visible planet as its "child". I'll have to try a few things.

Using a reference frame which explicitly is oriented toward the Sun seems to be the easiest:
Point its rotational axis toward the sun, and rotate around it.



See the Celestia WikiBook for more info, although it's rather cryptic.
http://en.wikibooks.org/wiki/Celestia/Reference_Frames

Hi thanks for helping me out.

Wonderful, it's working great.

You're very welcome.