[Aavso-photometry] W Aur Comp Stars

[arne]

Jim Jones wrote:
> I have two nights of V data from W Aur that is driving me crazy.  The 
> measured magnitude will vary by several tenths of a magnitude depending 
> on which comp stars I use.  I finally concluded that 13.2, 14.0, and 
> 14.1 are in error (F chart dated 12/70).  Using 13.1, 11.4, 12.1 in an 
> ensemble, I measured as follows:
> 
> 13.2          13.57 +/- 0.007
> 14.0          14.56 +/- 0.01
> 14.1           14.29 +/-0.01
> 
> Both nights data are consistent.  I figured that such a thing isn't 
> likely so I must be doing something wrong. But the new values result in 
> consistent measurements of the variable.
> 
> So is anyone else having problems with W Aur?
> 
This is not uncommon on the older charts (W Aur's sequence dates
from 1936).  They were using photographic photometry, or visual
estimates, not any kind of a linear detector.  Jim's data can
actually be used to correct the sequence and is the approach we will
be taking in the near future when the chart sequence team gets
assembled.

I note that the minimum in the light curve is pretty ratty, probably
due in some extent to the existing sequence.  That sequence ends at
14.5, while the CCD observations show the star goes a bit fainter.
Visual observers are pretty smart folk, and I would not be surprised
that they avoid the 132 and 140 stars entirely.
Arne