Hi Clever Ones.
I have tried and tried to understand this concept...and failed.
1: I know (or think) that ADU is an acronym for Analogue Digital Unit.
2: We can calculate the ADU value for a camera (using Gain, Bias, Read Noise).
Hear at IIS this value specific to a camera is called the 'Target-ADU'.
3: We can use a test image and find out the average 'Background Sky Level in ADU per second (Say: using the statistics tool in Pixinsight).
So I don't have to type all that again call it BSL-ADU
4: We then have to chose a sub exposure length that allows the BSL-ADU to be greater than the Target-ADU
OK, I still don't get it
Can some one explain what the above all means in plain English?
If there has to maths involved, well so be it.
I am just after the conceptual understanding, the maths can come later.