As you might notice from my avatar, I'm relatively new to the optical world of astronomy. A couple of questions with regard to dark frames taken with KStars.

Jasem recently pointed out that the dark frame capability is relatively new. I took a series of 5 darks at varying exposure times on my camera with the algorithm set to "Average" (only possible choice). The output FITS file contains 3 different frames. Just playing around, I saw that KStars would not let me take any fewer than 3 exposures for a given configuration. So, if I took 5 exposures, are the 3 in the FITS file the first 3? Where is the average?

Question 2 involves exposures in general, dark and otherwise. If I take a picture and display it in the KStars FITS viewer, the default view is Auto Stretch with values for Shadows, Mid-Tones and Highlights at the bottom. I can then select other View options, like Equalize, High Contrast, etc. If I go back to the Auto Stretch selection, I don't see what I saw when I started. If I adjust the Shadows, Mid-Tones, and Highlight values at the bottom to match the values when I opened the file, again I don't see "the original." Is that expected or ??

If any of you know of a definitive reference for dark and bias frames, please let me know.

Thanks,
Bob

I liked this description of darks, flats and bias frames: nightskypix.com/calibration-frames/

Maybe it‘s too basic?

Hmm. Basic or not, it's the first time I've heard of a "dark flat."

Thanks.