48'' Pointing Procedure

Oct 5. 1999 NC

After collimating, the pointing may be off, particularly in the EW miscollimation term (called CH in Wallace's TPOINT). In Harvey's PC-TCS, the "flexure" map is called Pctcs*.tp where * may be blank or letters a-d. Currently. it is "b". This file is found in the tcs.exe startup directory, which is now c:ntcs/testtcs. The file is pointed to via flexclass, which is reached by becoming "author" in the code. (Ctrl-BKSP and enter password.) Select "b" for that file. Note that flexure corrections must be also turned on in 3 places in the menu: rates, globals:parameters:display, and parameters:input:corrections.

When doing the pointing, note that coefficients are in arcsecs/radian. For CH, if the telescope has been zeroed at the zenith, and stars north appear offset to the east, then the CH value is too small.

As of Oct 1999, the CH value was around -60 (previously it was zero).

To collect data, go to author mode, select parameters:utilities:fdc. Make sure limits have been set right in globals.  The data will be
stored in Point.dat. The first line is a header, containing the date. This line is rewritten each time the program fdc is executed, but
the star data contained below that line is not erased unless you select purge in the fdc menu.  So, you can exit the program as
needed while you are collecting data.  When starting up fdc, you are warned it is about to begin - you must hit CR after this rather
than "any key" otherwise the program does not go into interactive mode (must be a bug).

The Point.dat file should be put on a floppy for analysis with tpoint.