When I last used my CCDSPEC spectrometer with its QHYCCD6 camera, I was concerned about the number of apparent hot pixels appearing on the image. OK – it did not matter as the nature of the spectrum meant a few hot pixels were neither here nor there but still I wanted my new kit to work properly!
….Then I noticed that I had not been turning on the fan – so tonight I took pictures of the night sky (without telescope) using Nebulosity – with and without fan turned on the QHYCCD6 camera. The effect of cooling by this method is dramatic for these 30 second exposures as you can see below.
NB The spectrum of the night sky is just visible in the middle of each picture (30 second images).
All images from tonight’s session, including FITS files can be downloaded here:
With fan TURNED OFF:
With fan turned ON – only a couple of hot pixels remain:
Dark frame of fan turned ON: