Today it was brought home to me just how dangerous it is to work on your own in this imaging business.  Tom How is a local guy and an imaging expert, and we only recently realised that we hadn’t met up for (too many!) years.  So Tom popped over to Brockenhurst this morning to see what I had been up to in the intervening years.  Tom also educated me about darks, bias frames and flats, something he has spent a lot of time on getting properly sorted out on his system.  It was when he showed me the bias frame from my M25C that he immediately knew that something was wrong with the camera – there was a large top-to-bottom gradient.  As I’ve never looked at a bias frame before it meant nothing to me.  However – it did kick me into action – and the long and the short of it is that (after mailing Terry Platt) it looks like the Peltier cooler is open circuit.  I have no idea how long the CCD hasn’t been cooled, but I suspect it goes back to when the power supply gave up the ghost a couple of years ago!!  Blimey – Noel and I have been turning out some pretty nice images without a cooled CCD.  We were getting a bit cheesed off with the hot pixels mind you – and I was very surprised (after having used the H9C for a few years) that I couldn’t do a decent job on CTB1, the supernova remnant in Cassiopeia.  Now we know why!!  So it is a trip up to Starlight Xpress ASAP for some surgery on the M25C and hopefully we’ll see a big leap in image quality brought about by some decent chip cooling!!  If Tom hadn’t popped over and pushed me along to see about bias frames and the like I would have carried on in ignorance.  This is the risk you run if you work on your own in this technologically demanding hobby 🙂


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