Modifications to Supercircuits PC23C

The PC23C from Supercircuits is seeing widespread use in videoastronomy due to its low cost, high resolution and extremely good low light sensitivity. However, in its stock configuration the camera ignores small brightly lit areas when setting the video gain. These areas then clip to white. This is generally acceptable for a security camera which has to be able to produce a usable image in shadows. However, it is not suitable for astronomical uses, and especially planetary imaging at prime focus.

Video AGC

There are now two modifications to the video AGC operation. The first clamps the video gain at minimum, and the second changes the way the video AGC circuit senses level. This modification reatins the full AGC operation yet reduces clipping on small bright objects.

Video AGC modifications

Manual shutter control at last!

There has been considerable interest in providing manual shutter speed control for the PC23C. Finally, someone has found a way! Charles Allison has scoped out the data sheets and the internals of the PC23C and has found a relatively simple way to provide manual shutter speed control, with some interesting twists.

Manual shutter speed control

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