Re: [vsnet-chart 155] Re: Chart of SN1999by > USNO mag seems not to gleatly differ except NGC 2841 2 star (it is on > the edge of NGC 2841), but I agree that observers should use Brian's > list as comparison. In this case, it looks USNO r magnitudes better fit V magnitudes than our formal transformation (V = r + 0.375(b-r)). The large and incorrect color indices in USNO magnitudes suggest the poor color calibration may have been the principal cause of the discrepancy. I don't see why NGC 2841 2 so largely differs in these catalogs (observers may as well check its variability). H/T magnitudes is consistent with the ground-based BV measurement. 092150.7 +510036 (2000.0) 1105 TYC3431.625.1 092150.7 +510036 (2000.0) 1105H 0.56 HIP045922 plx=6.65(4.01) (0.00 0.07) Regards, Taichi Kato