[Aavso-photometry] Transform coefficients and two-filter measurements

[Michael Koppelman]

You don't care about B or V you care about B-V and it is simply either  
redder or bluer. B-V is a single quantity, in a sense.

M.

On Jul 22, 2009, at 5:51 PM, tom_krajci at tularosa.net wrote:

> But with two-filter measures you have four possible scenarios:
> - B filter bandpass is bluer than ideal
> - B filter bandpass is redder than ideal
> - V filter bandpass is bluer than ideal
> - V filter bandpass is redder than ideal
>
> Hmmm, how do those four possible situations plot (X-Y) for  
> instrumental
> B-V versus catalog/ideal B-V?  All they all straight lines?...or do  
> some
> situations result in a clearly curved (second order curve?) plot?