I am seeing diagonal banding in my camera images. The camera is out of warranty as I am the second owner and I think it was purchased a while back. Would I have to pay to have this repaired or is this something DL would cover as a manufacturing defect? (I know I would pay the shipping) Thanks!
I obtained a used STF8300c and it shows diagonal banding in the lights and flats. Is this something that can be fixed?
Looks like someone attempted to clean the window, with poor results. Bill @ Service can clean that for you.
Have you tried a different power supply module? You sometimes see banding like this when the AC to DC power convertors become faulty and electrically noisy or if there is an earth leakage route via the camera to ground. The direction of the banding can be any angle between horizontal and vertical. Try connecting the camera alone and off the telescope to a different dc power supply or battery and test with cooling on and cooling off to see if that makes any difference. If using the camera tethered to a laptop try with the laptop powered by internal battery only, the same noise can be generated by leakage current from the laptops AC to DC convertor as it leaks down the USB cable to the camera. As Doug states it may be a dirty window, if the banding is identical in all images it is dirt, if the banding varies from one image to the next it is electrical. HTH William.
I'd take a bias frame - if it's still there it's electrical. But this looks optical, which will show up only on a flat or light frame.
Thanks Doug and William but I don't think it is optical, unless it's on the backside of the sensor window. Those dust motes are from recent teardown and reassembly out in the observatory, should have done it inside. I've cleaned the window and it had zero effect on the banding. The person I got the camera from had the same issue. I have used battery, AC, 2 laptops, usb cables, etc, same banding. The banding calibrates out with bias and flats. They are exactly the same from frame to frame, at least I can't tell the difference. I do not see the banding in the bias. If it is optical then I think there is something wrong with the sensor window or it is maybe on the chip itself. Is there a way I can test for either of those?
Hi Shawn If the banding calibrates out and is not in the bias frames then it can only be optical. It is unlikely to be on the sensor unless the camera was stripped down at some time in the past. If you use a strong light source at an angle to the port and inspect the window and sensor using a loupe or magnifying glass you should see any streaking quite clearly and be able to determine if it is on the sensor or the underside of the window. It might just be possible that some previous cleaning residue is on the sensor or the window and it only becomes visible when the camera is cold and the residue becomes a seed for condensate to form. While I have stripped and cleaned the sensor and window on several Starlight Express cameras over the years I have never pulled a SBIG camera apart so I would say the next step is to contact Bill Lynch for advice and a quote for cleaning if that becomes necessary, the webpage for contact details of Bill @ Service is here: http://diffractionlimited.com/support/technical-support/ William.
Awesome, at least we ruled out electrical, makes sense. I guess it could be residue on the outer window, I am pretty confident it has never been opened. If that is the case then maybe I will need to send it to Bill. I cleaned it with 90% Isopropyl and tissue but just the "drag and dry" with no force. Maybe it just needs a little elbow grease or something but I am loathe to get too much liquid in there or use any pressure. I know folks that use "lens pens" but I am not confident in them as there could be some grit that would cause scratches. I'll get a better look at it with a bright light and a magnifying glass and go from there. Would be nice if I were able to resolve it with cleaning! Thanks again, Shawn
Well pooh, just looked it over with a bright light source and magnifier, I can't find any trace of streaks, lines, residue or anything, at any angle. I will have to test the condensate hypothesis. Is it safe to open the shutter when the camera is operating with cooling? Seems like it would instantly frost/dew over the outside of the optical window.
Definitely avoid lens pens Shawn, most are impregnated with graphite and are unsuitable for cleaning the window or a sensor. Lens cleaning fluid containing Isopropyl on a lens tissue is fine but avoid holding the tissue with your bare fingers, the Isopropyl will dissolve the oil in your skin and transfer it through the tissue to the thing you are cleaning, I use disposable PVC gloves for that sort of work (the kind you find in food stores or gas stations are ideal). The important thing is to blow away any dust and grit with a rocket blower first, then wipe with a clean fresh lens tissue moistened with Isopropyl and then immediately dry with a fresh dry tissue, don't let the Isopropyl evaporate away from the surface as that is what leaves the streaks behind. Never use the same tissue for more than one wipe, use a fresh tissue for each stroke and no real pressure is needed, the Isopropyl does all the hard work. This is just the same method you would use for cleaning astronomical filters. HTH William.
Forgot to mention before, to check if the banding is present in the bias frames you would need to inspect the master bias made from fifty or more individual bias frames, there will be too much random noise in a single bias frame to show the faint streaking that is visible in your posted flat frame. William.
