Star trails

[arubaato]

I've had a number of attempts at star trails using digital (400D and 5D2) but have not had the patients of sitting around for another hour, and then another hour afterwards for the NR. So last month when a bunch of us when shooting, i decided to set my film canon SLR to shoot star trails while I used the digital to shoot other longish exposures. This is the result.

Does anyone know how to effectively remove the noise/grain without sacrificing sharpness? I tried noise reduction on PS but wasn't happy with the result.

Thanks.