[daip] question about weights in FITS-IDI

Walter Brisken wbrisken at nrao.edu
Fri Mar 21 14:38:31 EDT 2008


The weight vector that accompanies a visibility record stores weights on a 
per IF / per polarization basis.  The documentation I have suggests that 
this weight must be between 0 and 1.

Because of some subtleties in the DiFX software correlator, it is possible 
for the data weight to be slightly greater than 1 (with a hypothetical 
maximum of about 2).  This occurs when the integration time is not an 
exact multiple of the subintegration time.  In these cases, some records 
may have slightly less than full weight and some may have a bit more than 
full weight.  The mean weight would be 1 in the case of perfect data 
playback.

Will these weights that can exceed 1 cause any unexpected problems within 
AIPS?

Thanks,

Walter




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