[Aavso-photometry] Newbie Question Re: AW Cyg

[arne]

Sal Giambruno wrote:
> Dear Fellow AAVSO Observers:
> 
> Pardon my ignorance, and the basic nature of my forthcoming question, but
> I'm a newbie to the world of Variable Star Observing.
> 
> Having said that, I was wondering why, when I look up the characteristics of
> AW Cyg in a star catalog, say, an AAVSO database or "The Sky," AW Cyg is
> described as a variable star with magnitude ranging 11.0 - 14.5, yet, an
> observation which I made recently correlates nicely with current and
> historical AAVSO observations and light curves which show the visual
> luminosity of AW Cyg varying in the vicinity of magnitude 8.8?
> 
> There is obviously an error in my process or a gap in my understanding.
> 
> I would be grateful if somebody could shed some light on this for me (no pun
> intended).
> 
Hi Sal,
Like Wolfgang said, the 11.0-14.5 range is photographic and not visual.
With these red stars, you will see them *much* brighter with your eyes,
and 8.8 is not unexpected.  You can look at this star with the Light
Curve Generator (for those who are unfamiliar with this, go to the
upper left hand part of the AAVSO home page; enter
AW Cyg, click the box for "Create a light curve", and then press GO).
The default shows the last 400 days of variation of this star, showing
that it sits about V=9 most of the time.  Since you are a beginner,
I'd suggest that you pick another star, as this one obviously has
low-amplitude variation (difficult to measure until you get experienced)
and it might be more fun to look at something with obvious variation
like a Mira or frequent-outbursting CV.

The early discoveries of variable stars were often made using photographic
patrol cameras.  These typically had blue-sensitive emulsions, great for
discovering high-amplitude pulsating stars like Miras.  For some, the
basic information has not been updated in the variable-star catalogs.
If you see such old information in VSX, you can submit a correction - in
this way, VSX becomes more useful to others.
Arne