What Data Frames can be Used?

Practically all kinds of astronomical images, containing a number of stars and/or galaxies, can be treated with the INVENTORY commands. Up to now INVENTORY has been used or tested on data from the following instruments: Schmidt plates, CCD-frames taken with several telescopes, direct unaided and electronographic plates taken with the ESO 3.6m telescope. The applicability of INVENTORY commands is limited to frames that contain more than say 100 and less than 8000 objects. The lower limit concerns a single frame. If one has a number of frames each containing 20 or even a smaller number of objects, it is still worthwhile to use INVENTORY. A CLASSIFY/INV command requires:

• at least 20 stars and 20 galaxies to work at all, and
• at least 100 objects on a good clean CCD-frame, or
• at least 300 objects on a Schmidt frame

in order to work well. The upper limit is set by the dimensions of some internal arrays. Frames containing more than 8000 objects should be divided onto smaller subframes to be run separately.

Note

The CPU time required depends approximately linearly on the total number of pixels and on the total number of found objects (including defects). The demo frame with little over 100000 pixels and 200 objects needs 12.4, 10.7, and 2.5 sec of CPU time for executing the SEARCH/INV command, the base version of ANALYSE/INV command, and the CLASSIFY/INV command respectively with the use of the ESO VAX 8600 computer.