Quote:
Originally Posted by Peter Ward
Thank Greg….I am finding the CMOS adventure to be an interesting one. I’ve settled on Hi-gain mode for readout, with a gain of 64 for use with shorter than roughly 1000mm focal length instruments.
With longer FL’s I find my large pixel CCD’s do a much better job. (the math is simple: with my RC a 9 micron pixel captures 81 sq microns of well sampled flux from the sky,
even if it captures just 60% of the that flux I am getting nearly 50 microns of “photon detection area” at the focal plane.
Binning with CMOS doesn’t deliver any gains, so the IMX455 even at 90% QE only gives me tiny “photon detection area” that is massively oversampled,
picking-up 5x less flux per pixel…least that’s my take on it. Also the noise profile of the calibrated CCD frames are buttery smooth with no residual structure.
Getting back to the posted image, I keep the CMOS subs down to 3-5 minutes, as the small pixels fill quickly compared to my CCD sensors. To mitigate subtle banding I dither guiding for the sub-exposures
….a very easy task for MaximCCD which is my workhorse of choice for capture.
As for the Mach2…it’s my “portable” mount and has yet to see first light..or is that first lug? 
Looking forward to it. The Mach 2 sounds like a dream mount for a moderate payload.
The GTX piggybacks my RC on the PMEII in my backyard dome. |
Same except mine is on top of the RHA which is the guidescope!
There is also a new driver which offers another extended full well mode with even deeper wells.
Also one of the updated drivers (about 4 months ago or so) is supposed to reduce banding. I can't say I have seen much banding. Higher gain reduces banding somewhat.
Greg.