[vsnet-id 734] Re: (fwd) Re: [AAVSO-DIS] WW HYA

[Brian Skiff <Brian.Skiff@lowell.edu>]

>>  I used GSC 1.1.

     This has sometimes large systematic errors in many areas, amounting
to 4" in some places; errors of 1"-2" are common.  The "official" STScI
GSC v1.2, which was re-reduced against the PPM, is about 2x better and
nearly gets rid of the systematic problems.  Bill Gray's GSC-ACT is 
slightly better still (re-reduced against the ACT) when comparing with
v1.2 using such things as the ICRF radio sources, quasars in the Sloan
calibration fields, etc.  

>>  I didn't want to show the best astrometry, but simply to show the
>>  identifications.

     That's fine, but again you give the designation from USNO-A1.0, 
but do not specify this.  As you know, the A2.0 numbers are completely
different---never mind that they probably should not be promugated anyway
(so far the USNO-x.x products are rather transient, so introducing the
numbers into the literature only adds confusion).  Even B1.0 is likely
to be replaced in a year or so.
     In re IRAS names, there is no need to show the faint-source name
when a regular point-source ID is available.

\Brian

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