Pointing

Telescope pointing corrections involve three steps:

In the following all the code is on hill in ~treffers and below. Directories mentioned below are from that root.

Making the Observations

I run the scriptpointing/doall to generate the observations of known stars.

Patrick Wallace has compiled a list of FK5 stars 5th magnitude or brighter on a pitch of 20 degrees (TPoint/stars20b.dat). This list is then run through the visible program to determine which are up.

Then the list of stars is run through a list optimizer program to order the observations to minimize telescope motion. Here is a typical result.

Finally the telescope is pointed at each star in turn, and the observer is requested to use the paddle to center the star and hit return when the star is centered. The program then records the raw encoder readings and generates a file called run.dat. This file is in the format required by TPoint. Here is an example.

Analyzing the Observations

The output file from the above is then entered using the following comands:
indat run4.dat
use IH ID		#remove encoder offset
fit			#returns IH/ID values and rms of 66 arc-seconds
call e9

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