With this command the user can select a number of well behaving
stellar images to determine the Point Spread Function on the frame.
These well behaving stellar objects (of the order of 10 to 15)
should be chosen over the whole frame.
SELECT/ROMAFOT displays the frame (or part of it) on the
image display and allows the user to select the objects. The
image display cursor and its control box is used to select the objects .
Since this command is also used to select special classes of objects, (e.g. photometric standards) it asks for magnitudes and names of the objects selected. If these are unknown the default can be used.
After execution a set of subframes with given dimensions (typically 21 by 21 pixels) centered on the input cursor position and each containing one star is stored in the intermediate table. This table can be feeded to the the command FIT/ROMAFOT which actually performs the fit to the data. The table also contains trial values both for the sky background and the central intensity of the stars.