1. How does unity gain work
actually unity gain is where one ADU equal to 1 electron
this is just one easy way to calculate how many electrons you get
2. Is there a way to compute or test to determine the exact unity gain of a given camera?
yes, you can calculate by yourself, you can search on google and can find out how to do it
3. Is the unity gain unique per camera model or individual serial?
different camera has different unity gain
4. When should I use unity gain? deepsky?
yes, actually unity gain work like middle gain and is suggested to use do DSO imaging
5. I have an ASI224MC. In the configuration of the ASCOM driver have presets for:
-high dynamic range (gain 0, offset 10) (when to use? moon and sun since they're bright?)
-unity gain (gain 134, offset 20) (deepsky? highspeed=off)
-lowest read noise (300, offset 140) (planetery? highspeed=on)
If I use an app using native ZWO drivers, can I use the ASCOM presets as is? I think brightness=offset as the range is the same and gain goes up to 600.
this is because ASCOM driver is used to do DSO imaging
we limited the value to avoid customer make mistakes
6. What is offset and why/when use it? (seems to lower constrast)
offset is just avoid data clip by zero, so you don't need to worry about it because our ASCOM driver already set it well
7. Is there a way to compute or test to determine the ideal offset to use? I read people using histogram median values from bias frames.
just make sure all data higher than 0
8. For planetary on the ASI224MC ASCOM lower read noise preset, the offset of 140 seems huge. When I used it (gain 300, rightness 140 and higher blue channel in sharpcap), contrast was washed out.
planetary imaging is different from DSO imaging
you can use higher gain and lower exposure to freezing the seeing
I usually set exposure to 20-30ms and then adjust gain to make the histogram reach 80% of the full range