[vsnet-obs 42033] Re: V4334 Sgr CCD

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

Re: V4334 Sgr CCD

> The observation was unfiltered and I set the zero point of the image with V 
> band magnitudes from the AAVSO 1746-17g chart.  The observation was taken
> with the 0.81 m Tenagra scope.  I hope this explains the observation.

   This is not a correct way of reducing unfiltered CCD observations.
Since this field is reddened, the comparison stars should have large color
indices.  You should at least estimate Rc magnitudes of the comparison
stars (Rc ~ V - 0.5(B-V) for stars with 0 < B-V < 1.x), and report CR mag
observations.

Regards,
Taichi Kato

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