I just upgraded to the "max" version, but wanted to comment on this version. I occassionaly used this app for years, but since re-kindling my astronomy hobby I have found it to be an extremely helpful tool. I have similar programs for my Windows tablet PC, but this App is on my iphone & in my pocket! The night mode (red display) is really nice. The more you use it and understand its nuances the more valuable a tool it becomes. Great App! Now Im looking forward to using the upgraded version.