Affiliation
British Astronomical Association, Variable Star Section (BAA-VSS)
Thu, 05/11/2017 - 13:13
I have been using the AAVSO reference stars (mostly the V reference stars) I notice some in brackets figures like (0.075) superscript 29.
The 29 is APASS but is this a difference with their identified values?
All the best
John
hi John,
There are three pieces of information given for every magnitude in the table:
The actual magnitude
The photometric error (in parentheses)
The source of that information (superscript)
Along with a cross-reference table at the bottom. So for AF And, for example, the first sequence star has a label of 76, a photometric magnitude of 7.559, an error of 0.032, and a source of 1 (Tycho2).
The (B-V) color shown in the table does not have a corresponding source reference number because it is a derived quantity: the B magnitude minus the V magnitude. Those two magnitudes might come from different sources, so giving a single ID is not correct.
I hope that helps!
Arne