Paul - there's 2 moons in this image. Also - if you save your finished result in registax as a tiff then you keep more detail, TIF is 16 bits per channel, vs BMP at 8 bits per channel.
If you're going to try recovering detail in Astra Image then you need to keep as much detail as you can.
Astra image is commercial, but you can download a free version that does everything except save, and you get around this by taking screenshots to grab the finished image.
http://www.phasespace.com.au/
cheers, Bird