I'm a relative novice astroimager and have also experienced the anxiety of wondering what exposure times I should use. Thanks for any insight anyone can provide. Which one (using the SNR & Noise data) is the best and by what criteria do you use to determine that. In the attachment you can see I've taken 5 Photos, all at ISO 200 (the other settings the same as well) the variance is the length of the Subs. So again, can these SNR & Noise numbers in APP be used as a refrence to guage the amount of Signal in relation to Noise and say "Ok, at x min Subs my Downstream Signal overcomes the Upstrean Noise, so any thing above x min. □ That might say something about my state of mind. Gee.this really looks like an incoherent ramble, but it makes sense in my head. Once I know that point I (in theory) should be able to make better descisions about Camera settings to maximize what little time I have to gather Photons. In order to do that I need to find an optimal length for my Subs to be able to fill the sensor to it's Full Well capacity and make sure the Downstream signal overwhelms the Upstream noise, weither it be 20min or 40 min or 90min. So, I know I don't want to shoot higher than ISO 200 (on the 1000D's) in order to have the greatest Dynamic Range available to capture every last Photon. That point on my 1000d's is ISO 200 and on my 450d's is ISO 400.(article here: ). I understand "Full Well and ISO-Invariance" and the effects of higher ISO values on image quality etc.what I dont understand is how to interpret the numbers.Every sensor has a point of ISO-Invariance where it makes no sense to go any higher because it doesn't do anything but add more upstream read noise. I understand the concepts of ISO(Gain) in a digital camera and how it affects SNR, Dynamic Range and Read Noise. The reasoning behind this question comes from trying to up my game a bit from the Camera side of things. How do you read them and what do they mean? How can I tell which of a group of images has the best SNR ratio by looking at these numbers? I have spent hours Googling to try and find a "Number" that says Ok.any image with an SNR number above (for example - 5,5661E+00 - 2,1343E-03) is a good SNR Ratio, I can't find any examples that correspond to a number like this in APP. Hi everyone, I have a question about the SNR & Noise numbers in APP.
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