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Subject: [vsnet-chat 6327] RASNZ RS Oph sequence etc Dear Brian, Thanks for your data. > HOWEVER, it appears the results are NOT RELIABLE, and it was easy to > find stars where the V magnitudes were clearly in error by 0.1 - 0.3 mag. > The five brightest stars from the RS Oph sequence should be sufficient > to show the problem: > > > ID Name V B-V source > 6 HD 159358 5.37 0.02 Webbink > 5.56 0.01 Crawford, 1963ApJ...137..530 > 5.55 0.02 Corben, 1971MNSSA..30...37C A search through the GCPD makes it clear thaat the star is V= 5.56 (Luckily Webbink's results are not included) The same for the other stars. > relatively poor photometric quality of the site is probably > responsible for the problematic data. > I think Sebastian Otero found some > differences with ASAS3 for the RS Oph region---where there are discrepancies > for uncrowded stars, it's probably the RASNZ chart values that are in error. > RS Oph > ID Name RA (J2000) Dec V B-V U-B remarks > 156 HD 172768 18 42 17.9 -07 20 14 7.34 1.95 V453 Sct This is strange since V453 Sct is a small amplitude red variable with a recorded range V= 6.8 - 7.1. I don't think it has been this faint. B-V is no that red but ~1.74 > 169 HD 174796 18 52 25.7 -03 43 32 7.54 2.10 Which has 2 measures in the GCPD at 7.15 and 7.17 and B-V of 1.91 not 2.10. So, red stars seem to be 0.4 mag. fainter and B-V is 0.2 mag. redder..... I won't go on with the list. I prefer the ASAS-3 values.... ;-)) Sebastian.
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