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Hello, I'm glad to find this group. I have one of the first G3-16200 cameras and I'm extremely happy with it. The download speed is a bit slow compared Mk2 versions but I'm not complaining. Based on my very positive experience with the above camera, I wanted to purchase a second one to be used on my side-by-side setup only to find out that a CCD based camera was not an option anymore. With the kind help of Eva at Moravian, I ended up buying a C2-12000A camera. After years of resisting the CMOS revolution I finally gave in and bit the bullet. I'm still trying to come to grips with this different technology and would like to see some dark and light subs of other C series camera owners for some sanity checks. I would be much obliged if any C series owners can get in touch with me and share their subs. My initial feeling is a very big disappointment with CMOS since I was expecting much cleaner subs compared to those of high RN CCD subs. Thanks for reading. Clear skies Sedat |
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Hi Sedat, I have recently purchased a C3 26000C, still trying to make up my mind on the change from my G2 4000 CCD, but the results look promising. I can send you some subs if you want. How would you like me to send them? The FITS files are 50MB but I could save them as Jpeg to make them smaller. Clear Skies, Roger |
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Hello Roger, Thanks for responding. Congratulations on your new camera. Would love to see couple of fits files, like 1x bias, 1x dark and 1x light if it won't be too much of a work for you. Dropbox, Sendit or any other file delivery service of your preference would be fine for me. Thank you so much. Mine has a different sensor and having worked with CCD cameras for many years, I'm not happy with its performance . It appears that the sensor is not cooled at all, as privately explained to me by Moravian's Pavel Cagas. The sensor used in my camera, according to him, is difficult to cool because of its design limitations. Secondly, again according to him, the sensor is cooking the data before transferring it to the camera electronics. All this makes calibration a very diffcult task. I want to sell the camera but I cannot because my conscious says this wont be fair to the prospective buyer. Clear skies Sedat |
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Hi Sedat I am sending a Bias, dark, flat and Light on dropbox. Dropbox link https://www.dropbox.com/sh/dhsubojxm42lxew/AAAsnOqggiZiKjWc2xTVnQHAa?dl=0 These are the files straight from the camera, so not debayered or calibrated. Hope this helps. Cheers, Roger |
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Hi Sedat I don't understand your cooling comment, Moravian's website says the C2 12000A has cooling to 45C below ambient. Surely this is correct? Cheers, Roger |
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Dear Roger, thanks for the files. Much appreciated. Your files seem very CCD like. Mine look terrible compared to yours. Regarding cooling, the camera is cooled but not the sensor itself.. I have talked to many experts regarding this problem. Below are the comments from Bernd, who is really an expert "it is a simple calculation what to expect. Taking the dark at 17 °C captured with SIPS. The 210 "warm" pixels result in a mean intensity of about 1433 ADU. The normal behavior of Silicium-based photodiodes is that the dark current is halved when the temperature is lowered by T1/2 of about 6 K. Imagine the sensor is cooled from 17 °C to -20 °C, i.e. by 37 K. This is 6-fold the T1/2 of 6 K. So you can expect a decrease of dark current by factor 2^6 = 64. I don't know the bias offset exactly (you didn't capture bias frames), but according to the statistics of the darks it will not exceed the range of 235 ADU. The calculation then is; Measured dark current (mean of 210 pixels) at 17 °C = 1433 ADU - 235 ADU = 1198 ADU Expected dark current (mean of 210 pixels) at -20 °C = 1198 ADU / 64 = 19 ADU Instead the measured dark current for the 210 pixels at -20 °C is 1141 ADU - 235 ADU = 906 ADU. This tells you something about the cooling efficiency of your exemplar of the camera. My conclusion is: your exemplar of this camera is defect. If Moravian tells you that this behavior is normal for CMOS cameras, then they don't know what they talk about. Pavel should inspect your dark frames, take note of the above calculation and then give his opinion." In short, cooling has almost no effect on the warm pixels. I don't want to consume your preciious time with my problem but I have ample data to support this. This is acknowledged by Moravian themselves but they shamelessly keep selling this camera. I also have a Moravian made KAF-16200 based camera and I'm extremely happy with that one. Unfortunately, my second purchase from them was a mistake... Cheers Sedat |
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Hi Sedat, Were you able to find a resolution for the poor cooling of the sensor? I'm considering buying this camera but would rather avoid it if this is an inherent design flaw. Cheers DC |
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Hello DC, After my initial efforts, I stopped using that camera. However, NoiseXTerminator is doing a marvelous job in cleaning noisy frames so I may consider using the camera again. It is a great camera otherwise. Clear skies Sedat |
