Day 187 Thursday 2nd October 2014 Cepheid Variable CF Cas Calculation of its apparent Magnitude and Colour Inde

NGC 7790 contains three Cepheid Variables as shown in the AAVSO Chart. CE Cas A and B are variable elements of the same double star and very close so not within my equipment's ability to separate them to measure their magnitude. This paper "CE Cas a, CE Cas b, and CF Cas in NGC 7790" by J. Smak in 1966 looked at all three variables. This paper followed by Allan Sandage et al. in 1969.

This is my image in VPhot with the target, comparison and check stars shown and an expanded view of CF Cas

 This is the result of the untransformed photometry

 

 I repeated the photometry with the B image of NGC 7790 and obtained a B magnitude of B = 11.598

So B - V = 0.409.

I will continue with this star in future blogs.