Data Flagging

There is an extensive system of data flagging, which begins with the raw data, where the saturated pixels are found, bad pixels noted etc. These flags follow the pixels all the way through the data reduction system, and when stellar images fall on flagged pixels, they inherit the flag. The flags are easy to understand letters, e.g. S for saturated, which makes it likely the user will read and understand them. If they do, it gives them considerable flexibility in accepting data with particular flags.