A stack of four 10 minute exposures at iso400 through a 200 mm F5.6 lens. I really need to get a handle on processing these RAW frames for best results...
Autoguiding now seems to work quite well, here's a comparison between 10 min frames with guiding on/off:
More exposure is better, this one has about 40 min in total, previous attempts had only about 12 min and 8 min.