[vsnet-chat 852] Re: Sequence near NGC 3067 by Angione

[aah@nofs.navy.mil]

I've reduced my CCD frames from last night of this sequence mentioned
by Brian Skiff.  These frames were taken on a non-photometric night, so
the zero points for B and V were set by the published magnitudes/colors
for stars A,B,D'.  The results are then:

    Star    V     B-V        pubV   pubB-V
       A  13.060  0.700      13.07   0.70
       B  13.765  0.463      13.75   0.46
       C  13.976  0.911      13.96:  0.89:
       D  13.393  0.596      13.20   0.62
       D' 15.146  0.817      15.15   0.82
       E  15.438  0.922      15.45:  0.96:
       F  16.378  0.103      16.18:  0.29:

Formal Poisson errors are <0.02mag.  As you can see, stars D and F are
somewhat different from what was given, and star D is definitely not V=15.20.
  The new V, (B-V) values are not to be considered 'secondary standard'
quality.  However, since these are CCD measures, the internal accuracy
(star-to-star) should be quite good, with just a zero point adjustment
to get the sequence on the real Johnson system.
  (NGC3067 is quite pretty)
Arne
--------------------------------------------------------------------
Arne Henden                               Instruments/software/CCDs
US Naval Observatory Flagstaff Station    Cepheids/photometry/IR
P.O. Box 1149                             http: ftp.nofs.navy.mil  
Flagstaff, AZ 86002-1149                  Voice: (520)779-5132
aah@nofs.navy.mil                         FAX:   (520)774-3626

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