Re: GSC 00279 00321

[aah@nofs.navy.mil]

As far as classification is concerned, TASS has a definite
advantage over most other surveys, since you have simultaneous
V and Ic photometry.  Not only does it allow you to use
the Welch-Stetson variability index, but it also: gives you
a clue as to the spectral type; gives you information as
to how the color changes during the variation period; permits
transformation onto the standard system; allows removal of systematic
errors from atmospheric extinction; and knowing
the colors of the nearby field stars helps in selecting comparison
stars of similar color and avoiding those spectral classes that
are likely to be variables themselves.
  For these 11th magnitude variables out of the galactic plane,
you can generally ignore any interstellar extinction and assume
the (V-I) color is intrinsic to the star.  A general table of
(V-I) vs. spectral class can be found in Allen's Astrophysical
Quantities.
Arne