[vsnet-chat 1436] Re: RS CrB

[bas@lowell.Lowell.Edu (Brian Skiff)]

     I would recommend using Vj from the Hipparcos/Tycho catalogues down to
V mag. 10.0, or until the errors shown for the stars exceeds 0.05 mag.---
perhaps this will take you to V=10.5.  It so happens the GSPC sequence for
this region is immediately south of RS CrB, and so could be used to extend
the sequence somewhat fainter.  Some relevant stars are:

Name        RA  (2000)  Dec         V    B-V
P274-B   16 00 29.2  +35 52 19    10.49  0.56
P274-C   15 58 27.4  +35 50 14    11.36  0.72
P274-D   16 00 14.0  +35 42 11    11.89  0.84

The GSC magnitudes for these three stars are very consistently 0.15 brighter
than true V.  Thus to get fairly reliable V magnitudes for fainter stars
close to the variable, select GSC stars in this magnitude range and _add_
0.15 to the GSC magnitude to obtain V.  Choose several candidate stars
and then check the results visually to see that the corrected magnitudes are
consistent.

\Brian

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