Hi ! I have an old ST2000XM from around 2004 and from last year the images have banding on the lower half. please see the attached image. I have seen somea threads here concerning banding but I´m not shure the answers apply to my camera. Can the source be a bad usb cable ? Regards Timo Nordberg
The old cameras are USB 1.1 and don't have frame buffers, so need a quality USB cable, preferrably directly connected to a dedicated port on the computer that is not shared with other USB devices. Can you post a FITS image? Perhaps a bias and dark as well.
Hi Colin ! Next time clear skies appear I will test a new quality usb cable. I enclose a FITS img. Dont have bias or darks for the moment. Thank you for taking your time with your reply to my question Rgds Timo
You've processed the image, so I can't tell what's going on. The only thing I see is a bit of a thermal gradient and some vertical column noise. Since the camera is 16+ years old, the capacitors in the camera and the power supply will have degraded (this is normal for all electronics) and this might account for some of what is going on. I'd really like to see a bias and maybe a 1 minute dark.
He may also have a computer that is doing something else while downloading the image. If the CPU is “stolen” from MaxIm during image downloading the rate of transfer will vary and... banding. Those old unbuffered cameras are seriously painful. Along with Colin’s primary advice, also check to see that nothing at all else is running on your PC while you are imaging. This includes automation programs like CCDC, SGP, CCDAP*. Also there may be a “priority” setting for that camera in MaxIm. Set it to High. In the past at least, this would force MaxIm to set its CPU priority high and lock out other software during an image download. I hope I am not overstepping my boundaries here. * If you Are using ACP it’s OK to let it run, it knows about this and puts itself to sleep during image downloads.
That’s all good advice, Bob. There is a high probability that download interruption from other programs is the cause of the problem. Our modern cameras do not have this problem because they have frame buffers.
The ST2000XM connected to CCDOPS is whats running on the laptop. No other programs or devices in other usb ports. I enclose 2 bias img. and 1 dark img. 60 sec. What is your opinionof these ? Rgds Timo
I use CCDOPS for simple imaging and APT or SGP for advanced imaging and sequencing. But always only one program and one device at the same time Timo
