[daip] MATCH

[Eric Greisen]

Andy Biggs writes:
 > Hi Eric. I've been doing some digging to shed some more light on the 
 > problem. I use ANBPL to display the hour angle of each data point; the 
 > output from MATCH is shifted by -8 hours compared to the input. I then 
 > modified TI2HA to print out a number of its variables. GSTIAT has changed 
 > after executing MATCH, by the same number of hours.
 > 
 > The reference date of the master file appears to lurk somewhere in the 
 > MATCH output where it is used by the hour angle routines. The dates of my 
 > master file and the file on which I run MATCH differ by almost exactly 16 
 > months; sidereal times separated by this amount of time differ by -8 
 > hours. This appears to be the cause of the problem.
 > 
 > Unfortunately, my AIPS programming skills are limited and I don't know 
 > where the hour angle routines are getting GSTIAT from. The observe date in 
 > the header is the correct date of observation, but as I mentioned, the 
 > reference date in the AN table is that of the master file. Changing this 
 > with TABED makes no difference to the hour angle routines.
 > 

Yes - the error was subtle and has to do with the header of the master
file AN table becoming the header of the matched AN table.  I have
fixed it if you run a 31dEC07 MNJ today.

Thanks for your help

Eric Greisen