On 9/7/2010 3:22 PM, robinriordan wrote: > This may be a related question to Cliff's. I have been observing SU > Cyg and use Tycho-2 2151-4816-1 as a comparison star. I have found > discrepancies in the magnitude across different star chart programs. > > Cartes du Ciel lists m=10.10 Meade's Auto Star lists m=9.54 C2A lists > m= 11.443 > > Has anyone else noticed this? How is it possible that different > values are reported for the same Tycho star? > > Robin Riordan
Catalog values for magnitude vary all over. Also, you need to know what band the magnitude is. I looked up TYC 2151-4816-1 on SIMBAD and got a B magnitude of 11.2 and a V magnitude of 9.92, for still more numbers. If the planetarium programs don't quote a source for the magnitude, etc., I would be reluctant to use the numbers for anything serious. Bud [Non-text portions of this message have been removed]
