Vega (alpha Lyrae)
Canon EOS5DMk2 254mm Newtonian @ 1200mm 64 x 2s f/4.8 ISO3200
I was interested to see how atmospheric turbulence affects images on the shortest possible timescales. Extrapolating from my chart of saturation magnitudes I reckoned that it should be possible to image Vega in 1/2000s at ISO 6400 without quite saturating. Tonight was cool but very still at ground level and here are some frames from a sequence I took, magnified in GRIP to make the pixels visible.
At this time of year at latitude 54.8°N twilight never ends so there was a little background light pushing the result just into saturation.
A stack of 73 such frames resulted in this: