Hello, On Nov. 9, our STXL-6303's coolers stopped in the middle of an imaging session. Once we realized they had, we turned them back on as quickly as possible, but there has been a noticeable change in the sensor. We have vertical streaks (one prominent) in our images that were not present before. They're significantly more obvious at 2 binning than 1, and are evident in biases as well as other images. Since then, we have taken test images but have intentionally kept the camera's set temperature high because I am concerned what may happen if we continue to cool/heat it repeatedly if there is a fault already due to thermal shock. If the new flaws are only due to change in the circuitry, I hope it will be okay to continue using the camera as usual. (I am crossing my fingers that the fact we're only seeing a few vertical lines means that's the case). We should be able to correct the artifacts with darks. If the flaws may be coming from one or more cracks, I imagine a new sensor is in order, but I know servicing for these older models is limited. I am also concerned that the coolers simply shut off. Since then, they haven't done so. I'm not sure if the issue was with the camera or something to do with the software. We never let the cooler power sit above 80% and it's usually significantly below that. My overall question is whether it's reasonable to continue operating the camera as it is, or if we should send it to you for a check-up and possible repair. I'm pasting in side-by-side comparisons of 1 vs. 2 binning for biases and 1 sec - 120 sec darks. I've also attached the original fits files. Thanks in advance, Jamie P.S. Looks like I'm going to reply to this to include the other files. There were too many.
Typically if the cooler shuts off, it's because the camera is protecting itself against too low an input voltage. As the voltage drops, the camera's internal power converter draws more power. If the voltage gets too low the current could get high enough to damage connectors, etc., so the camera shuts down the cooler automatically. Is this powered directly from the supply that came with the camera? Are you using through-the-mount cabling? (Those arrangements often have insufficient wire gauge to support the cooler at full power.) As for the bright column, that's not a surprising thing per se - sensors are subject to gradual cosmic radiation damage over time and can develop new hot pixels and columns. What is a bit weird is that they seem to be smeared horizontally. In fact the hot pixels in the image look smeared also. That suggests the CCD isn't being clocked correctly. That might be due to an internal power supply failure. I suspect the camera requires service. If you would like to do that, please fill out this form: http://diffractionlimited.com/request-rma
Thanks, Doug. We use the camera's power supply, and we do not use through-the-mount cabling. We do plug the camera into a surge protector. I'd noticed the smearing on the very obvious line, but not on the other hot pixels. When I zoom in, yes, it is very clearly strange. Thank you very much for pointing this out! I'll fill out the form. We removed the camera from our telescope yesterday. In the bright light, it was easy to see the fans on the back are quite dirty and the surface of the metal cages around them has a fair amount of rust. Should we clean this first or send it to you as is? Also, do you want us to send the cabling / power supply? We got a little lucky with the timing in a way. We just received a larger aperture telescope that we needed to swap out with the previous one, so we'd have down time regardless.
I'd include the power supply and cable, because we can check that. Up to you if you want to clean up the fans... we'll do it if you don't. If you want to go ahead and return the camera for service, please fill out this form: http://diffractionlimited.com/request-rma
