I wanted to use an astronomy program to check a Maya calendar inscription in the distant past. This program can only accept dates as far back as the start of the Gregorian calendar in 1582. Older dates have to be entered as Julian day numbers and the resulting date display is meaningless. For what I wanted this app is useless. A big advantage of the Mac platform is that the GUI in all applications (including the finder) is consistent. When the developers invent their own creative GUIs like the one in this application, users are confused and frustrated.

This program appears to require the user to have administrative privileges to run it.

My benchmark test is to go to the date April 17, 6 B.C., to see, whether the software correctly shows a lunar occulatation of Jupiter near Aries. Also, I want to change the view to that seen from Babylon at that time.

Compared to Stellarium, it was much more difficult and not immediately obvious how to accomplish these. The date display did not distinguish between A.D. and B.C., the difference being apparent only from the fact that going backwards in time caused the year to increment. It was also not easy to simply enter the date.

I'm curious how this is different from the free "Celestia." Is it worth the $50?

http://www.macupdate.com/info.php/id/7020/celestia