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Old 13-06-2016, 02:55 PM
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Shiraz (Ray)
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Join Date: Apr 2010
Location: ardrossan south australia
Posts: 4,918
Two more experimental images with ASI1600mm-cool CMOS

The M16 in Ha was 24 subs of 200seconds each. No calibration of any sort was used - it was dithered. The seeing was pretty bad (the guiding was running at about 1.2arcsec RMS_ - normally not suitable for imaging). The gain was set at 100 and an initial sub was 300seconds - however, the atmosphere was so turbulent that it messed up the stars and I changed back to 200 sec to give something like roundish stars. Although it is quite soft, was pleasantly surprised at the smoothness of the result. This is the full image - 3meg so a bit slow. Wanted to show how the 1.25 filters affect star shape in the far corners - the full 16mpix will not be available with the small filters. I am coming to the conclusion that, with a bit of care, calibration is not essential for good SNR with this camera - a little bit more light exposure may be a better use of time than calibration of large numbers of subs. Plan to do some tests and quantify how much benefit there is from calibration.

full size: http://www.astrobin.com/full/252173/0/?real=&mod=


The moon fits easily in the field of the 1600 camera with a 1000mm fl. An AVI sequence was taken at 8 bits, 5ms?, gain10? and about 1-2 frames/sec full frame. The best 25 of 100 frames were stacked in AS!2 (lucky imaging software) and finished off in PixInsight. Again, the seeing was not good, but the very short exposures had the effect of freezing the occasions of better seeing and the result is not too bad. This is not a DSO, but it seemed appropriate to post here, where current users of the camera post. Fan was running - no obvious sign of vibration effects.
small version http://www.astrobin.com/full/252168/0/
full size crop:http://www.astrobin.com/full/252168/0/?real=&mod= NB you might have to pan around to find it - there is a lot of black sky.

By the way, taking sky flats with this camera is a doddle - with a download time of about 1 second on my system, the whole process (under bright sky) can be over before the sky changes enough to require a new exposure setting.

thanks for looking - these are experimental images, so would appreciate feedback. Regards Ray
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Last edited by Shiraz; 14-06-2016 at 09:05 PM.
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