Setting the Low and High Cuts

Great attention should be paid to proper settings of the low and high cuts. They were previously entered as a parameter of the NORMALIZE/IMA command. Now only the original frame is used and it is not truncated by the applied cuts. The program needs proper values of cuts in order to avoid using incorrect data. In order to find acceptable values of cuts one has to redisplay an image several times with varying values of display cuts. One can, in this way, fix low cut as a level just below all the good data with only bad pixels having smaller values. High cut should be placed below the saturation level. The data may be distorted even at some distance from the saturation level and the program tries to take this into account. Therefore, in a case where none of the frame stars are saturated the high cut can take any value, that is to say, at least twice as large as the highest pixel value for any stellar object.

As the frames need not be normalised, low and high cuts should be entered in the same units as pixel data.