[vsnet-chat 5795] Re: [AAVSO-DIS] survey, pixy etc

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

Re: [vsnet-chat 5788] Re: [AAVSO-DIS] survey, pixy etc

>      CR,CI  unfiltered ("clear"), zeropointed onto the Rc,Ic systems
>             (the assumption is that you use the bandpass that most
>             closely approximates the response of your unfiltered CCD)

   No conveniently available commercial CCDs have a response close to Ic
(although there exist ones closer to V).  So I don't find a justification
to use CI.  In my opinion, I don't recommend to use the specifications
other than the widely used "CR", since these system specifications have
already introduced additional source of confusion; I know several people
who believe that one can get V magnitudes using V-magnitude comparison
stars, and R magntides using R-magnitude comparison stars, and further
extensions, even from a single (unfiltered) CCD image.

Regards,
Taichi Kato

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