Hi! A friend of mine is using a SBIG STT-8300 camera with a 6'' telescope but the data we're getting has some wierd streaks and wave-like patterns in them. Two things are bothering me. First: If you look at these three calibration files of different exposure lenghts here: https://www.dropbox.com/s/jlzzrz6mx249fad/CCD-waves.zip?dl=1 when you stretch the bias and dark frame, you can clearly see a wavelike pattern: http://imgur.com/a/Gaw5j This is present in both bias and dark frames, even though one is an 1/100 sec exposure and the other is a full minute. The waves aren't in a fixed position from image to image, the peaks and troughs, the angle of the waves and the vertical location of the 'wave lines' all shift from image to image. Is this a normal thing to see in this camera? In the 1 minute dark frame exposure I would have expected that the image was very smooth, save for hot pixels. Any idea of the cause of this or how to best correct it? I have 10 bias frames which also each exhibit this phenomenon, and after integration the wave pattern is nearly gone, which indicates that it's somewhat random in nature. Second: In this stretched 10 min exposure of M51: http://imgur.com/a/eOeFz#1B2XqWR some very well defined noise lines are running across the image. The noise seen here looks like it might be of a different kind, since it's not wavy, like the first kind. Should I expect this kind of noise in the images produced? -- Best regards, Jes Hansen
It's definitely not normal. That's some kind of interference. Are you using the power supply that came with the camera?
Hi, It's my camera I am using the power supply that came with the camera yes. Anything I can do to test or check the camera? I am using the Ethernet connection to collect the images. Could the noise come from interference in this cable? A number of cables are running very close to each other since this small telescope+camera is mounted as piggy-back a larger telescope (1m): http://phys.au.dk/typo3temp/_processed_/csm_IMG_6217_b67e94d32a.jpg Kind regards, Mads
Possibly some kind of interference. Try shutting everything else down and take a bias frame. If the noise is gone, then switch things on one at a time until it reappears. Then we can deal with that. FYI, the noisiest system in many observatories is the mount servo drive.
Hi Doug, I am finally at the site again. I have unmounted the CCD and tried to do a bias frame in a completely different environment. The interference is still present. I even bought a new power supply from SBIG to test if this was the cause. It had a small effect but the interference is still there. I have read in the manual that there is a internal power regulator. Could this somehow be damaged? If so could I test it? Are there any other test you could suggest me to try?
Yes it is probably an internal power supply failure. Please contact Bill @ Service - see http://diffractionlimited.com/about-us/contact-us/
Hi Doug, After contacting Bill Lynch he recommended me to ship the CCD to him. This I did and according to DHL it was delivered on the 15th of November and received by Bill. I have not heard a thing since and tried to contact Bill a week ago without a reply. Do you know if anyone has looked at it? I have a scheduled trip to our observatory (which is on Tenerife 4000 km away from where my office is in Denmark) in March next year and I really hope it would be returned at that time.
