[vsnet-chat 1530] Comparison star of R CrB

[Taichi Kato <tkato>]

Comparison star of R CrB

   Some of our observers have noted that the following comparison star of
R CrB (closer of the two nearby 7-th mag stars)

GSC2039.642 154740.76 +282810.0 (2000.0)  7.50 4
GSC2039.642 154740.82 +282809.5 (2000.0)  7.17 1
154740.8 +282807 (2000.0) SAO84005 7.8 7.3 F2
154742.6 +282731 (2000.0) HD141352 7.43 7.77 F2
154740.8 +282809 (2000.0) 743H 0.47 HIP077373 plx=10.81(0.87) (0.01 0.01)

has been recently assigned a magnitude of 7.4 in "The AAVSO Variable Star
Atlas, Second Edition", while older AAVSO charts assigned it the magnitude
of 7.2.  There have been arisen several questions:

  1) When and on what charts this revision was made?

  2) When individual observers have switched the magnitude from 7.2 to 7.4?

  3) What magnitudes were/are used for this star in VS organizations of the
world?  (The VSOLJ has traditionally used the magnitude 7.2, as taken
from the old domestic handbook of selected AAVSO charts, published under
permission of the AAVSO).

  4) If the switch to the new magnitude has been made, how have been older
estimates treated?  Have they been rescaled, or left as original?

Regards,
Taichi Kato

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