That's a really interesting method, Alex. So, do I understand correctly that each image was a 0.32 sec exposure? Remarkable. 

A short exposure does mean that you get good resolution even at the centre of the cluster.

Is there the possibility to integrate for longer? And can the image be processed to remove dark pixel or hot pixels should there be any?

Thanks Jeremy.

Analogue video cameras pump out frames at a constant rate of 25/sec (PAL standard, 50 interleaved fields/sec). Models like the Watec 910 can integrate, so they can be set to internally stack 2, 4, 8, 16 or more frames, then output a steady stream of these integrated frames. OccuRec can read this stream and individual frames from its resultant file can be saved as BMP, FITS.

In this example I used an integration setting of x16 (16 video fields = 16 x 0.02s exposures = 0.32s) and adjusted the AGC (gain control) to optimise the view, balanced between reaching a good lim. mag. and avoiding overexposure from local light pollution. The video integration and gain can be adjusted to bring out different features. This stacking from 8-bit video cameras doesn't match the well depth achieved by 16-bit CCDs, although expensive 12-bit video cameras are available.

Just like with standard CCD images, you can also take video darks, video flats, video bias recordings of a few seconds' duration. Tangra can process these and create dark and flat BMPs and apply them to the video. This is useful when recording an important event such as the Triton occultation, where Paris Observatory requested that darks and flats be included in our data submissions.

much appreciated. Hopefully you will share some more images taken this way in the future.