[vsnet-chat 4270] Re: vsnet chat topics

[Taichi Kato <tkato>]

Re: [vsnet-chat 4265] Re: vsnet chat topics

> When trying to interpret a star's behavior based on visual data,
> there is inevitably going to be uncertainty involved. There is
> usually about a magnitude of scatter in visual observations, and I
> find it not at all unusual to have a mix of "fainter than"
> observations in the midst of the positive data. That is fine.

    Even CCD observations may suffer the same kind of bias.  As may be
well known, reporting only positive detections (or successful software
measurements) can lead to overestimation of the true stellar magnitude.
This is particularly true in eclipsing CVs, which can easily reach
very low light levels at eclipse centers.  The same effect is present
in virtually any measurement; the effect is simply most prominent in
visual photometry.

    [There are a lot of other subtleties in CCD photometry of faint
sources.  I omit them here for simplicity.]

Regards,
Taichi Kato

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp