Hi, The attached image shows the noise from a 240s dark frame. This looks abnormal to me. I would expect mostly point sources of noise with some cosmic rays or such. Any idea what causes the "rain" effect? Image details: 240s, -5c cooling on, single dark frame.
Can you send a FITS sample image? What is the serial number written on the camera? What software and version are you using?
1) had trouble uploading so: https://www.dropbox.com/s/2hu39hjv3b14hh1/Autosave Image -001DARK_240S.zip?dl=0 2) 100210395XME 3) This is taken with MaximDL but have tried CCDSoft and CCDOps with the same result. Thanks, Roger.
I have now done some more testing. The rain noise seems to be introduced by the cooler. Turn cooling off: no noise, turn cooling no: longer rain for higher power cooling, shorter rain for lower power cooling. I tried another USB cable just in case and that made no difference. When you say power do you think the power supply might not be functioning 100% ? Interestingly the same power supply has been used for two different ST10's now which have both recently been diagnosed with cooler troubles (this one with rain noise, the other with non-functioning cooler but normal noise). That said, this camera I'm not sure if it had problems when last put in to storage.
We found a link to someone detailing the same problem: http://www.hiddenloft.com/notes/CamPwr.htm Seems power supply/cabling was their culprit, so we'll definitely look in to that.
We eliminated this "rain noise" by changing power supply. Unfortunately we're left with other issues! But, for the rain noies it seems the power supply was the culprit.