Hello everyone, today I turned on my Sbig stf mono and I noticed a vertical line. What do you think could have happened? I tried to replace the USB cable, but the line is always visible. The line is visible both with dark and with luminance. Greetings to all.
This is actually normal; all sensors experience some gradual deterioration over time due to radiation damage. CCD sensors are impacted by cosmic rays and ionizing radiation from nearby materials (especially concrete and gyprock). Over time these events cause tiny defects in the crystal lattice, eventually resulting in artifacts like this. This is not really a problem. The impact of hot columns is reduced greatly when the sensor is cooled, and then dark subtraction typically removes them completely. So please cool the camera down, and take a new set of dark frames. I think you'll find that the line is completely removed by calibration.
Doug hello thank you for answering. I'm not expert on the subject, but I do not think that the CCD deteriorates over time. And even if it is not normal because I bought it for about a year and a half ago. I did several tests with low temperature, but the line is always present. Also I changed USB ports, and also PC, but the line is always present. The last shots I made last week but the line was not there.
CCDs definitely do develop hot columns over time. I have a KAF-6303 sensor that had no columns in 2001, but now has half a dozen very bright columns. They all subtract out. Try subtracting a dark frame.
Doug I did like you said you, I lowered the temperature at -20, and the line and disappeared almost completely. But you think you can fix? The CCD is still under warranty.
The sensor warranty is one year. See http://diffractionlimited.com/terms-of-sale/ We would not charge for labor, but you would have to pay for the replacement sensor. That said, I would not recommend doing this. Given that it has disappeared almost completely at temperature, dark subtraction will completely eliminate the column.
Thanks Doug, I used the Astroart function "Correct" column in the pretreatment step and disappeared completely. Do you think they can go out the other columns in the future? How much is the Kaf sensor 8300?
I strongly recommend that you NOT use column repair. That is used to interpolate across a badly damaged column. This is something you can calibrate out and get a PERFECT image. Take a fresh dark frame, and perform normal calibrations - i.e. regular dark frame subtraction. The line will disappear. Yes it is possible for radiation damage to produce additional columns in the future. Hopefully that will not happen for years. Again, even if it does happen all you need to do is take fresh dark frames and perform the normal calibration steps.
I did a prva with two dark with the same acquisition time but at different temperatures. One at -15 to -20 and the other, I have for the moment only ones. If you look carefully lacolonna even a weak one is still visible. Here in Italy I come from the weather is bad and I can not buy additional dark.
The subtraction has to be performed with frames taken at the same temperature. Otherwise the column will not subtraction perfectly, as you have found. Also I can't tell anything from a JPG image. It would have to be FITS.
