Folks,
Being cooped up under the clouds gives the grey matter a little too much (but not enough) time to think about imaging
So let's get down to it...
Imagine that on the same night I had two imaging scopes, with the same f-ratio - a small scope and a larger scope, with 2x the objective area. Let's assume equal optical quality to take that out of the equation.
Imagine I also have a different sensor at the back of each. The pixels in the sensor on the larger scope have 2x the area of those of the sensor on the back of the smaller scope, resulting in the same resolution per pixel. The sensor with larger pixels has comparable QE/sensitivity to the smaller sensor, but costs 2x the read noise of the smaller one.
Then I point both rigs at the same object...let's say it's a galaxy...and the object doesn't fill the FOV of either sensor. The image is exposed sufficiently on both rigs to overcome the read noise and maximise the dynamic range.
What's the difference in the image from the two rigs?
Cheers,
Dunk