Demonstrating Annual and Retrograde Motion
I feel like this was asked a while ago, but I do not see it.
I would like to show annual motion and retrograde motion with the stars staying in one position and not slowly progressing across the dome. With the annual motion button selected and if I select a time interval of days or sidereal days, the stars still move across the sky. This is still kind of confusing because you have to watch both the planets and the stars to see the positions change.
Is there a better way to do it? I was easy with an optical-mechanical because the planets where on separate motors from the stars. You could very clearly see the planets move against the background of the stars.
Service d'assistance aux clients par UserEcho
Hi Paul,
I think what you want to do is to step through time with a time step of sidereal days/second without annual motion on. This will keep the stars in the same place and you will see the movement of the sun and planets only. Is that a little more what you are thinking about?
Yes, that works, but I have to keep clicking the "skip ahead one time step button" to get the planets to move. Is there any way to put it in motion and still keep the sky stationary?
What would also be cool is a why to lock onto an object like the Moon, a planet, or a comet and have it stay in one position on the dome. I understand that the camera/ viewer would then be traveling over the surface of the Earth, but it would be a good way to show Moon phase, the phases of Mercury and Venus, or a comet changing over time.
It's possible, from orbit mode (with the Earth off) to lock to a constellation/planet and watch this effect. There is also a retrograde motion module in the community content area that ay help with this. As with your other question, I also do this with stepping by sidereal days to keep the stars still while letting other objects move. There was a thread about this on the users group a while ago too that may have more answers.