I have too problems. Not sure they are related. The first problem is dark horizontal lines extending from bright stars You can see this in the stacked OIII image. There is also smearing of hot pixels horizontally in the dark that I suspect is part of the same problem. --------------------------------- My second issue is that I noticed a varying background noise in my NB images. I made a FFT of the read noise by subtracting a master bias from a single bias. It produced the last image showing a non-random pattern consisting of thin vertical lines. Please help Thanks Max Mirot
Here you go. Dark https://www.dropbox.com/s/wdydzzwf53aib9t/-30 2019 10 26-0010D30.fit?dl=0 Bias https://www.dropbox.com/s/43r4r3am48slglf/-30 2019 10 26-0011B.fit?dl=0
The background should not be an issue. If calibration is done correctly it will subtract out. I am more concerned by the trails behind the stars. Can you supply the light frames?
https://www.dropbox.com/s/9i0ww09zm..._BIN1_-30C_011_20191022_212951_270_E.FIT?dl=0 https://www.dropbox.com/s/8140f72ll..._BIN1_-30C_016_20191020_014544_021_E.FIT?dl=0 https://www.dropbox.com/s/jyk89y9u8..._BIN1_-30C_001_20191025_193019_728_W.FIT?dl=0
I'm not seeing anything like the streaks in your first light image. Was that a single frame? Do you have the raw FITS file for that frame? What is your camera serial number?
I must be not understanding. These are raw fits taken with MaxIM DL. They have not been calibrate or altered by software unless I picked the wrong directory. I am not at home so I don't have the Serial number handy. I will it get tonight Max
Max - I just had a look. The Light_frame.jpg is a JPG subframe of an image, and the OIII and Ha images you provided are of a wider field, centred pretty much on the same thing, but there is no evidence of a problem. So, we're looking for the images that you used to produce the light_frame.jpg.
Sorry. This is definitely a Pixinsight processing problem. I will let you know more when figure it out. Thanks Max
https://www.cloudynights.com/topic/682800-unknown-ccd-artifact/ I have not been able to fix this with changes to calibration and processing. The problem has been seen before. Cameras were sent back to mfrs for clocking adjustment and firmware changes. My firmware and drivers are current. Max
https://www.dropbox.com/s/jyk89y9u8..._BIN1_-30C_001_20191025_193019_728_W.FIT?dl=0 This is a raw single frame. It is invisible to me
Max - good talking to you today. Turn on RBI preflash in MaxIm, and I expect that will clear up the few ghost images in that last frame. I suspect the processing tool to remove the ghosts in PixInsight is causing a bit of that effect you are having. The Cloudynights issue looks like a trailing charge problem with QHY cameras (known issue with them). From my experience, the SBIG STXL-16200 and another manufacturer (non QHY) don't have those artifacts. In short, turn on RBI, and then see how you make out.
I am returning to images after 2 year break. I still have the horizontal dark streaks coming from stars in my STX 16803 . The stars don't have to be very bright. The artifact is most noticeable in narrow band images. RBI mode does not fix the problem. I was wrong before. I do not think it is due to processing. However, I can't detect the streaks in the raw or calibrated frames fully stretched. It is obvious once they are integrated. Would a stuck shutter cause this ? Max