On night of Septembter 10, 2011, 28 images on the almost full moon were obtained at 0.015 second exposures. We compute the mean level of these images. They are dominated by the full moon, the sky flux is negligible, and the moon is well centered.
The mean count rate for these frames is 5546.7 counts / 0.015 sec and the standard deviation of the mean counts over all 28 frames is 8.4 counts – if this standard deviation is all due to shutter timing error for these frames, the timing error is ~1.4%. On these short timescales the shutter timing is at least this accurate. 
Longer sequences with bias frames in between the lunar exposures would be good. None of the frames dropped out, but we know that this can happen occasionally, with as much as 20% of the frames dropping out.
