Observing in Monochrome using OSC camera

[mgCatskills]

I'm doing a fair amount of Arp observing, where the key features -- like narrow filaments -- are very challenging to see in a one shot color camera stack.

I find myself converting the color images to Gray/16 and processing them after the fact. Often, though not always, inverting them. This is usually much more effective in revealing faint details than I can accomplish in color.

Can I short-circuit the post processing and get Sharpcap to combine the luminance info from all for sub-pixels to give me a Gray/16 image? I'm aware of invert button on the display historgram, so I would expect to use that regularly after conversion to mono..

Assuming this would work, how would my 294mc-pro perform compared to a 294mm or similar monochrome camera?

Michael

[admin]

Hi Michael,

starting at the end, a colour camera will always be limited to about 1/3 the sensitivity of a mono camera - that's because there is a colour filter in front of every pixel. The ones in front of the red pixel absorb (and therefore throw away) the green and blue light, the green pixel ones absorb the red and blue, and so on. Therefore, only about 1/3 of the light collected by the telescope actually makes it as far as the photosensitive parts of the sensor. Unfortunately no clever processing can fully recover from that loss.

On the subject of being able to get things to show in mono in SharpCap, there are a couple of possibilites. Probably the best is to use 2x binning and then set the option to use monochrome binning which should be in the 'Misc controls' section for your ZWO camera. That will give you a monochrome image in SharpCap (well, actually, it will be a colour image with all 3 colour channels the same - it will look and act like a monochrome image though).

Another thing you could try is to turn the 'Debayer Preview' control to 'Off' - this will stop SharpCap from debayering the image, so you will see the RAW pixel grid in monochrome. The typical chessboard pattern of a raw image will be visible if you zoom in, but when zoomed out, it should look like a mono. This approach avoids binning, but will limit the use you can make of live stacking, since the alignment functionality is unavailable when in this configuration (trying to align and stack with the grid pattern present causes a nasty mess of interference fringes).

Hope this helps,

Robin

[mgCatskills]

Very helpful, Robin thank you. And a very clear explanation.