frustrating comet lovejoy

[Ianstraton]

ok I know I should have gone to this location while the comet was still bright but frankly I was too scared I would get robbed or worse...

Anyway here is panorama (consisting of 15 subs) of the milkyway and comet lovejoy over Table mountain and cape town. The images were taken with a modded 550d 18mm lens and astronomik cls clip filter (I'll leave it to your imagination what the scene looked like without the filter... lets just say there aren't so many stars visible!) iso 400, f3.5, 25 second exposures. The subs were loaded into photoshop and merged using the photomerge tool then flattened to a single layer and cropped to remove the worst of the stepping produced by my shot selection.. the resulting image is presented here (reduced in size and converted to 8bit jpg to get it to a postable size, the 16 bit original is HUGE) as you can see there is a strong gradient emanating from the bottom left and overall the colours look a little strange but the main issue is just how faint the objects of interest are within the general glow.

I have tried selecting out the mountain and city and processing the sky separately this sort of worked but the junction between the sky and the mountain ended up looking very very "fake" which was disappointing, I have also tried creating a star mask with the aim of dropping brightness of the sky background but I found that I couldn't separate the comet from the sky glow.

Any processing suggestions would be welcomed..