M31 the Andromeda Nebula - 5-1/3 hours
click image for larger (50%)

almost perfect fit for the 600mm and aps chip... north skewed a little .....
58 five minute and 30 minutes of short subs for a combined 5 hours and 20 minutes exposure with the Vixen ED80 at f7.5
the first 290 minutes in one session (the sun came up in frames 59 and 60)....

captured using Nebulosity, bad and warm pixel conversion, base color balance, flat frame, and ddp in Nebulosity
gradient removal, noise ninja final color balance and jpeg in Photoshop CS3

Vixen ED80 at f7.5 (no corrector) riding on my Meade Classic LX200 12 inch, Hap mod 350d,
guided by PHD, DSI Pro on the 12 inch at f5.8 --- sky good but moist, about 2 arc second

enjoy