In this post I won't go into details on how to input camera and telescope information, or, how to input images into the program, but, just give an overview to show some of the features of the program. If there is sufficient interest I could prepare a "tutorial".
The image below shows the Image analyzer tool where the various images (taken with your sensor/telescope combination) are input. To characterize your sensor noises as well as determine your optimum sub exposure time you will need to input: 2 Bias frames, 2 Flat frames, 2 Dark frames, 1 Light frame (actual target image), and 1 Saturated frame where at least some of the pixels are saturated. The Files window in the image below shows I have input all of these images.
Once the data is input to the program you can switch to the Image Calculator window which is shown below.
Here the sensor noises are shown (bottom left box) as well as the noise contributions to your Light image (bottom right box). For my system the Sky Shot Noise (
The Plotting Tool is the tool I use to determine the exposure time for my subs (images). I use the Stack SNR vs sub exposure time graph. This graph for my system is shown in the image below.
This graph shows how your choice of exposure time for your individual images will affect the quality (SNR) of your stacked images. For my system, exposures of 300 - 400 or more seconds will produce the highest SNR which means the best quality. Thus, my exposures of 540 sec are well suited to my camera/filter/telescope combination.
Your system will likely have a different graph, but, the shape will be similar with a sharp rise at the beginning, a "knee" in the curve, and a relatively flat region for longer exposures. Any exposure time longer than the time at the "knee" will produce your best results.
This is a short introduction (many features not mentioned), but, hopefully it will whet your appetite to look into this program. It has given me high confidence in choosing the exposure time for my images.
The program can be downloaded (Windows and Linux) at: http://lars-frogner.github.io/Astrophot ... nload.html
Steve