Thank you for your response.
I have to admit that I am an impatient Astrophotographer. If the night is clear and the equipment is all working well, I will start with short exposures of 10 seconds (depending on the target), then 20, 30 60 120 and even 180 seconds. Usually my guiding starts to break down somewhere between 1 to 3 minutes, so I am limited there by my equipment. What I find is that for long exposures I can begin to 'see' the object (Nebula or galaxy) and so I start to take more of those exposures. But what I sometimes discover later is that the sky noise was to high or the stars are blown out and so I have a difficult time processing the data as I have to blend multiple exposures.
So optimizing the exposure time is important and knowing how many subs you will need to take to bring the object out the noise clearly. But, I am not the inclined to spend many multiple hours on a target. Usually what I can get in one evening is going to have to be good enough. I think more of us fall into that category than those who have permeant observatories and can spend multiple nights on a target.
I am trying to do the best I can in a limited time and I am not sure that fits very well with Dr. Glovers approach. But I believe his math. The capability of image processing software is in a constant state of flux. I have only just used the StarNet Star subtraction capability in Siril, so that I can stretch a starless image.
I guess what I am saying is that I understand it is complicated by all these factors. I am looking for something that guides me at the moment, with the object in view, that says this may be a way to proceed. A dogmatic approach that says that 300 ten second images on target will get you an image with a SNR that exceeds a certain value just does not seem to help. First, that is 5 hours of image collection and second if I cannot get those 5 hours have I just wasted my time.
I am not trying to take pictures for APOD, I am just trying to enjoy the hobby with results that I am proud of and amazed that I can produce an image of something that far away.
Sorry, for the digression. I appreciate what your exposure calculator is providing us with and I will have to spend more time with it.
I had a good night and collected a bunch of data. This is the result of simple processing of a half hour of 60 second exposures (I have more images at longer and shorter exposures but I had the most at this exposure)
I will spend some more time with the data to see if I can clean it up better. But I am struggling to decide where the most effort should be applied.
Thanks again