Fix coordinates of ALFA Mock psrfits data from beams 1-6 (data taken up to 28 Jan. 2010 are affected).
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.gitignore
Makefile
PALFA_MOCK_Coords_Table_110903.txt
PALFA_MOCK_Coords_Table_110903_allbeams.txt
PALFA_MOCK_Coords_Table_110903_beam0.txt
PALFA_MOCK_Coords_Table_110903_mismatches.txt
README
alfa_offsets.tcl
alfaoff.c
azza.c
cal2mjd.c
deg_trig.c
findmismatch.m
fixbeampos.c
glgb.c
polyco.h
prec.c
prec_proto.h
psrfits.h
radec.c
read_psrfits.c
showbeampos.c
write_psrfits.c

README

*** Before compiling: change the path to alfa_offsets.tcl in alfaoff.c to point
to where the file is on your machine.


Fixbeampos fixes coordinates in the main header of Mock psrfits files taken
with ALFA up to 28 Jan. 2010. Up to that date, coordinates in the headers 
and rows of side beam (beams 1-6) data files were not calculated correctly by
the Mock data-writing software. Data files from beam 0 are fine. 

Data with HDRVER of 3.43 or greater in the main header are not affected. 

The program needs a beam 0 file--it will use the positions in its header and
rows to calculate the correct positions of the side beams' headers and rows,
and will correct the side beam files if they are present in the current
directory. HDRVER in the main header of side beam files will be changed
to 3.43. A new field FIXDATE will be added to the main header of side beam
files to record the date on which they were corrected. 

Fields fixed in main header:
HDRVER, RA, DEC, STT_CRD1, STT_CRD2, STP_CRD1, STP_CRD2 (the latter two pairs 
of parameters are "start coordinates" and "stop coordinates", which are equal 
to RA,DEC)

Fields fixed in rows:
RA_SUB, DEC_SUB, TEL_AZ, TEL_ZEN, GLON_SUB, GLAT_SUB

The calculated RA, DEC, GL & GB for side beams based on beam 0 values are 
within a few arcsec of actual positions (from tests on data where both header 
and rows positions were correct for all beams). The calculated AZ may be 
up to 1.5 arcmin from actual positions, but that is a "small circle" angular
distance and may be very large at small ZA. The "great circle" angular offset
is AZ*sin(ZA), which is just a few arcsec.