There is a huge difference in a Celestron CG5 GT Mount and an AP Mach 1 GTO. Even if you were to push the load limits it would still track better than mine.


In that thread they briefly touched on the mathematical formula, I don't worry about the math, instead I prefer practical application and seeing with my own eyes.


Signal remains a constant from one exposure to the next, but the noise in each exposure is random, and when you stack multiple images the noise cancels itself out.


Increasing the SNR you're also increasing the Dynamic range which might make it appear, or make you think that you have increased exposure length, when instead you're only revealing those fainter details because there is less noise blocking them. Does that make any sense?


Anyways, I was one of those who thought multiple exposure added up to a greater exposure length, E.g 10 x 60 seconds would equal to 10 minutes exposure. I was wrong, through trial and error I have learned differently.


The best thing I can suggest doing is to experiment; on the same object if you can. You can even do it in your home with your camera and camera lens taking pictures of a gray card or something. For Example take 40 x 30 second exposures to stack and process, and also take 20 x 60 second exposures to stack and process, and then compare the differences.


I think were a lot of the confusion comes from is from SNR and people equate the Signal to an accumulated exposure length.


If you really want to get those faint details you will need longer exposures. I try to push my exposure to the maximum limited by the skyglow, not the noise level evident in each exposure due to the high ISO. That will clean itself up with enough exposures/light frames, and darks, flats and bias frames.