Posted 13 September 2013 - 10:53 AM
Any experience with UCAC4 in terms of reliability of given magnitudes?
Posted 13 September 2013 - 02:34 PM
It is true that these catalogs disagree with each other but there may not be one catalog that is error free, UCAC4 included.
Posted 13 September 2013 - 03:48 PM
... by what authority do you declare them to be incorrect?...
Simple facts of observation - if I cannot resolve for example a 3" +9.5/9.8mag double (did I say Jonckheere?) with my 140mm refractor then the data is wrong. Or if you have three +11.3mag stars in an open cluster plain to see obviously different bright then again. And the higher the magnitudes the higher seems the error rate in the usual used catalogs. UCAC4 is certainly not free of errors (how could that be with this number of entries) but I hope it is for higher magnitudes the best available catalog. If you know something better please let me know.
Posted 14 September 2013 - 12:39 AM
There might be a research project lurking. Someone interested who encounters such a problem could do a visual estimate of magnitude using companion stars. Then one could see how the estimates compare with the suitably transformed (to Johnson V) magnitudes in various catalogs.
Just a thought...
Posted 20 September 2013 - 12:53 PM