The input/output have been made compatible with Midas, but the algorithm
has not been changed (as it proved to be extremely accurate, this would
have been masochism). In this release, the user interface has been considerabely
improved and the program has now the capability of finding its astrometric
standard stars on the Internet, without any
help from the operator.
While the original POS1 was doing everything in one programme, the MIDAS version has been split in 3 steps:
In most cases, step 1 and 2, including the automatic creation of the table of USNO-A1 reference star through the internet, can be performed almost completely automatically through ASTROM/AUTO.
A demo image is included, together with the corresponding files and
output, in order to test that the program works well on your system.
In the "automatic mode", the reference stars are identified using a "map" that is plotted over the image, as shown below:
An astrometric solution is then search iterativelly; at each iteration, the residual map is displayed (stars in use are green with a red residual vector, stars rejected are red):
In the same directory, another gnuZipped tar file (pos1_example.tar.gz) (3.4Mb) contains examples (image and tables) to test your implementation.
Some support can be provided by Olivier Hainaut (ohainaut@eso.org),
to whom bug reports and suggestions should also be sent.
O.Hainaut, 2000 Feb 5
pos1_2003-02-26.tar.gz pos1_2002-06-22.tar.gz pos1_2001-11-05.tar.gz pos1_2001-09-22.tar.gz pos1_2001-07-11.tar.gz pos1_2001-05-11.tar.gz pos1_2001-02-14.tar.gz pos1_example.tar.gz