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CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 2:32 am
by oopfan
Hi Robin,
Do you know of any sub-$1000 CMOS cameras that have a Full Well in excess of 15,000 electrons?
Thanks,
Brian
Re: CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 9:43 am
by oopfan
Never mind. I see that ZWO has a handy comparison chart. Too bad that most desirable models are color.
Re: CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 1:39 pm
by admin
Sony 174 sensor if you are happy with big pixels? 32k FWD.
cheers,
Robin
Re: CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 2:15 pm
by oopfan
Yes, I saw the 174. Too bad its 12-bit and not 14-bit. The big pixels mean that I would have to swap in a focal extender or buy a longer refractor for photometry. It is never easy is it?
The 290 works for now. It gives me 3.5 magnitudes of linearity with SNR > 100 in a single frame. I'll wait for the technology to advance.
If I had taken the AAVSO course earlier I would have purchased the 178 instead of the 290 for only a few dollars more. 14-bit ADC instead of 12-bit. 2.4um pixels instead of 2.9um. 3040x2048 pixel array instead of 1920x1080. Same 15k FWD.
Re: CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 2:46 pm
by turfpit
Brian
Sell the 290 to fund the 178?
Larger pixel arrays bring their own set of problems i.e. big mega pixels = big data and the capture machine has to be able to handle it plus the storage requirements for post processing increase.
Dave
Re: CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 2:52 pm
by oopfan
I'll hold onto the 290 and use it as a guide camera when the time comes. One of these days I'll have a better mount that is capable of active guiding. My ASI120MC has got the jitters. I only trust it with polar alignment.
Re: CMOS cameras with Full Well > 15ke-
Posted: Sun Feb 25, 2018 3:31 pm
by oopfan
Given present-day technology a pixel's FWD is proportional to its size. In other words, if you want greater FWD then you are going to have to accept a fatter pixel. ZWO's high-end "Pro" cameras have FWD ranging from 46k to 76k and the pixel size is 4.63um to 5.97um. CCD's are renowned for their high FWD but they too have large pixels.
Unfortunately short refractors are not compatible with fat-pixel cameras. Ideally for photometry you want to have stars in the range of 2 to 4 FWHM. A fatter pixel sensor will lower it to 1 to 2 FWHM which leads to under sampling. Your choices are de-focusing or switching to a longer refractor. Longer refractors put greater demands on guiding.
So I think that the proper purchase order of upgrades need to be:
1. Better mount that is capable of auto-guiding.
2. A focal extender for my current short scope or purchase a new, longer scope for photometry.
3. A new camera with high FWD and fat pixels.