The Tpoint Package

Introduction

TPOINT is a unique software package which analyzes telescope pointing. It has been in use on major telescopes around the World for many years, from the Keck telescopes, ESO VLT, ALMA and GBT downwards. The principle of operation is very simple - you look at stars spread around the sky, recording the telescope readouts on each occasion, and then feed the information into TPOINT. Using powerful but easy to use interactive modelling and graphical commands, you can then identify and measure misalignments and flexures in your telescope. By including in your telescope control system the correction model that TPOINT has found, the various effects are compensated and the pointing errors drastically reduced.

Documentation

Documentation is at http://www.tpsoft.demon.co.uk/tpoint.htm, and the manual is here.

Initialisation

on C/Tcsh:

setenv PATH /usr/local/tpoint/bin:${PATH}

Version

The current version of tpoint is 21.5 Purchased June 2015.

Testing

tpoint
 indat aat15
  .aat
  .e9

Should show graphs of the AAT pointing accuracy.

end

To quit

Conversion Programs

Pat Wallace also provided a FORTRAN program called bristol4 for coverting data fromt the format generated by the Coldrick system to a format acceptable for tpoint. The source code and executable are in the tpoint bin directory and can be run directly from the command line once the setenv command above has been executed (sometimes the 'rehash' command is needed to remind some shells to look for new commands).

To use the bristol4 conversion program, do the following:

bristol4 < coldrick_format_data > tpoint_format_data

If the executable complains about missing libraries, then you will need to initialise the Starlink software collection, using the following incantation:

source /star/etc/login
source /star/etc/cshrc

There is also some test data here: 131228_W3-I5X_2013Dec28.txt

Rhys Morris

Last modified: Tue Jul 10 10:27:47 2015