I am planning to get an ASI6200mm but have been using a FLI Proline 16803 as my main imaging camera now for over a decade.
I usually judge new gear by the images I see posted as often people are enthusiastic about the latest gear. To be honest I have not seen any ASI6200 images that are outstanding yet. A couple that were impressive. I saw a good Saggitarius Trio image from a QHY600 that was very short exposure yet it looked like a long exposure image. That showed off how well matched this camera is to an FSQ type setup.
FWC of the 16803 is 105,000 electrons with 1x1 binning. It handles very bright stars very well.
So keep that in mind. 1x1 binned images have 121mb file sizes. 16803 are 32.8mb. 3.76nm pixels ideally only suit shorter focal lengths, 9 micron pixels do the full gamut from FSQ106 to CDK17.
The 16803 is all about its huge field of view. Its 50% bigger than the 6200. That's massive and the huge FOV of the 16803 creates a unique image that seems to really please viewers.
The 16803 does form vertical lines in the sensor over time. My 16803 is about 13 years old possibly a tad older. It had no vertical lines in it for a long time but now it has one brightish line and sometimes a few smaller not bright vertical lines. These sometimes calibrate out and other times they don't. You can set up a defect map or they are easy enough to remove using Photoshop healing tool in the later versions of Photoshop that tool will remove a line by clicking the start and then holding down the shift key and clicking the end of the line it will remove a straight line. PI also has a cosmetic correction App which I believe will remove them if set up correctly.
Binning on CMOS is only software binning. You still get an increase in SNR but its not as effective as binning on a CCD. So the QE advantage of the 6200 would be weakened compared to 2x2 binning on the 16803. The smaller pixels would mean oversampling on many scopes also weakening the QE advantage. I see some QE advantage of my 84% QE ASI183 but not as much as you might expect compared to a KAF16200 or 16803. Its there, its not massive though.
Smaller pixels do have some advantages though. I find I get rounder stars as each star is made up of more pixels and gives a rounder appearance.
But they also make it harder to focus. On my 16803 focus was pretty easy and easy to see when you nailed it. With the 183mm its much harder but not super hard but I wanted to make the point its harder. Also much more prone to the seeing.
As to noise my 16803 is very clean at -30 to -35C. Sure there is some but noise is not an issue as what little there is calibrates out easily.
CMOS sensors do seem prone to varying fixed pattern noise. This looks like little horizontal lines of darkness which vary from sub to sub. It won't bias out because its shifting. Luckily it seems to disappear in processing once stacked. I would use dithering though with these cameras.
So bias on these cameras is an odd ball. They don't seem to work.
Cooling on the ASI6200 seems quite weak. 0 to -10C seems practical in the sense of not much noise but dark current isn't the only gain from strong cooling. Maybe less important with a CMOS but there are still gains. I would have to do a side by side comparison but with the extensive imaging I have done so far with my ASI183mm, -25C cooling seemed nicer images than -10C. Not 100% sure of that though as other conditions may have been more relevant. The Proline 16803 does -40C often and -30C all year round, perhaps even -35C.
Having to shift gain and offset is a bit of a pain. CCDs are simpler there and less complication with having to have a large suite of darks/flats.
Everything has to match. This is worse with QHY as they have currently 3 modes on top of gain and offset plus they are planning to offer 8 modes. Sounds good in one way and a total pain when it comes to processing your files trying to get everything matched up exactly.
There are some reports of banding where some say its not a problem and some say it can be.
Owners of the 6200 though seem to be very happy with the camera and would recommend it. The 6200 is about 1/3rd the price of 16803.
My `6803 is a FLI Proline and its very large and heavy. Probably weighs something like 2-3kgs. It puts stress on the focuser. The 6200 is light in comparison. The 16803 requires 50mm square filters which are expensive the 6200 50mm round which are still expensive but less so.
But new 6200 type cameras will continue to come out as Sony makes new sensors for its mirrorless cameras (the 6200 sensor I believe is the same as what is in the Sony A7riv camera). Whereas the 16803 has ceased production so if you want one then now is the time whilst there is some stock left.
Having said all the above I am still personally excited about getting a 6200 camera but I would never sell my 16803 for it.
I don't quite get why people are doing super short exposures and stacking hundreds and taking days to process the calibration files. I use 300 and 600 second subs on my ASI183mm at -25C and it works great.
By the way lowered dark current is not the only benefit from deeper cooling.
In summary I think it would depend more on your planned setup. If you have a long focal length scope like a CDK12-20 inch or similar type then the 16803 shines in this sort of application. If you are planning to use an FSQ or similar shorter refractor setup then the 6200 should shine there as well but the 16803 still works just fine and will give a 50% larger field of view (that also means an expensive scope to be able to illuminate such a large field - 54mm versus 44mm for the 6200)
My 2c worth.
Edited by gregbradley, 11 August 2020 - 04:41 PM.