Looks great, however, the first question EVERY one is going to ask: WHAT ABOUT MY PRESCIOUS FRAME RATES? As you know this is a big issue.
Any insght for us?

Hi loomex,
  I did some tests on the Comet west bitmap. It's a relatively large bitmap. AutoStar works by converting every pixel (except black pixels) to a star. Therefore if you're not careful a large bitmap will create a large number of stars and frame rates will fall.

You can help frame rates in two ways. First, when creating or editing a bitmap, ensure that all dark/non-displayed pixels are black (RGB values 0,0,0). Black pixels are not converted to stars.

Second, there is a minimum brightness setting. For example, if you set it to 10 then pixels with average brightness of 10 or less will not create stars (a pixel of brightness 10 would probably be invisible, anyway).

In my test, without the comet the frame rate was 20 FPS.

With a minimum brightness setting of 5, 81000 stars were created and the frame rate was in the range 12 - 15 FPS, so there was a significant impact. A large proportion of the created stars was so dark as to be invisible.

With a minimum brightness setting of 20, 16000 stars were created and the frame rate was around 18, so there was only a small impact. The comet still looked essentially the same.

With a comet and a number of user objects plotted (e.g. a lunar eclipse and some Messier objects) well over a hundred thousand stars can be created (the manual recommends you don't exceed 150,000!) If there are a number of user objects the impact may be small because only a fraction will be in view at any time. In all my testing I've never noticed a frame rate fall that was serious enough to affect the overall experience.

I hope this helps.

Best regards,
   Chris