I recently got a chance to play around with the ASI1600MM-Cool camera. Because the chip is much larger than what I'm used to, I used a skywatcher 0.9x coma-corrector. I might need to do some tweaking still to get it in the perfect position, but for now it already seemed to produce a pretty flat field.
In order to reach focus I had to mutilate the plate the focuser is positioned on, right below the top ring of the 16" Dobson, and move it forward 4cm. I messed up the exact position though, so this is definately something I want to look at later, but for now it works 'OK' with some tweaks to get decent colimation again. I also created a hand-controller for my EQ platform that can be connected to the Arduino driving the EQ platform tracking motor. It works very nice, it's much easier to control everything with 'real' buttons instead of using the laptop touchpad... My soldering skills - like my ATM skills - are not that good, so it takes a bit of time, but the programming of the Arduino software is a bit easier for me. I didn't manage to motorize the declination control, I need to think this through. I'm getting used to the manual declination control anyway.
The ASI1600MM camera seems to work very well. Judging from this recording - containing only 34 minutes, with exposures of just 1 second each - the depth is already pretty impressive. I'm quite happy that I can do live-focusing at 10fps (and full res) without any problems; I like my camera's fast. This is also the first time I had a camera in my hands that can do cooling - which is probably not needed for 1 second exposures, but perhaps it will be during warmer nights (and for sure when using longer exposures), but I'll test the dark-current to be sure in the following weeks. The cooling is easy to use anyway, and it should help at least a tiny bit, so in the end I decided to just use it for now anyway (I set it to -15C, which it reached within a minute or so, and then it stayed there during the rest of the night... ).
Processing 40GB of data really is quite a challenge. So far AutoStakkert! manages to plow through it though, and stacking with two-pass sigma-clipping (.. I didn't know there were that many satellites out there!) took about 20 minutes. Without sigma-clipping it should take around 10 minutes I think. Either way it will take a bit of patience to find the correct settings; I certainly wanted to try different processing techniques to figure out how everything was working. In the end I think post-processing (and writing this message..) took more time though, so the stacking time is still acceptable to me.
Unfortunately the seeing wasn't very good, so I had to downsize the final image to get a reasonably sharp-looking image. The short exposures already help quite a bit with keeping the stars smaller though. A day before the seeing was much better, but I was stupid enough to not really make many recordings then (a few minutes worth of M13, and a few other targets with similar total exposure lengths. I still need to process them, but it will take quite a bit of time).
p.s. I don't want to start a discussion here too on CMOS v.s. CCD sensors, the future of deepsky imaging, # of APODs, and more stuff like that. Any other comments or remarks are certainly more than welcome though!
P.s. Click here for a better (less compressed) version of the image: http://www.astrokraa...l_Kraaikamp.jpg
Edited by MvZ, 09 May 2016 - 03:13 AM.