Sam Falvo

Great, I have set the saturation level as you suggested. I have a better understanding now of how to read the ADU values. I will modify my routines and break out the grreen channel before I do any calibrating. Even though after separating the green channel, the display continues to show three values I will no longer worry about the Red & Blue numbers. Next clear night I will give it another shot ... Thanks again !!! Sam

Hi Han, My camera is a Nikon DSLR D500 with crop sensor. As such it is is a one shot color CMOS sensor. So, my original NEF Raw image is in color. Should I extract the green channel from the raw image before I take any measurements? Will that affect the photometry if I do this before any calibrations are applied? Sorry to take up so much of your time on what I thought was a simple question! Sam

Hi Han, Here is my screen shot. In the bottom bar, after the pixel position equal sign, you can see the three values in parenthesee I am refering to. Sorry to be a pain, perhaps the ADU values should be labeledas such? Sam

Hi Han, Thank you so much for answering me. In my copy of ASTAP, when I hold my cursor over a star, there are three numbers in parenthesees following the equal sign. Can I assume these relate to the ADU in RGB? I am using a Nikon D500 camera body. Also, how do I interpret the star profile? I assume when the graph has a flat top the star is saturated, but if it has a peak, or several, it is not. Thanks once again!!! Sam

Hello, Just a simple question (I hjope), How can I measure the actual ADU of a star to determine if I am saturated? I have a 14 bit camera and need to stay under 16,384 ADU. I see a lot of jargon, and it may be displayed somewhere, but as a newbie I can't seem to get a definitive answer. Thanks ... Sam