Thanks! It has been an amazing experience, if a bit exhausting (I am a single founder and the only developer). I did it because it was cool, started giving them to friends, and then it became obvious that they were making a very large impact in some people's lives. So I decided to try to reach a larger audience, which had the nice side effect that now I can make a living from it.

I am using the stereographic projection, and I display up to magnitude 7. The conversion from magnitude to diameter is one of the key elements of getting a beautiful result.