Re: [AAVSO-DIS] IO Aurigae and the STARE eclipser Aur0 3503

[Sebastian Otero <varsao@fullzero.com.ar>]

> > TASS data have a +/-0.2 mag. scatter so there is no way to tell if there
> are
> > eclipses or not since the amplitude discovered by STARE is only 0.07
mag.
>
> Could you explain how you arrived at the scatter above since it does not
> appear to be consistent with the data in our S&T note 10 at
> http://www.tass-survey.org/tass/showtell/st0010.html

Tom,

Brian has already answered the question.
This happens all the time in different fields (not crowded).
TASS observations for some stars are good and for others are useless. I
don't know how this comes to be and why it happens. In the example above it
becomes pretty evident what makes the errors to stand out easily: almost
simultaneous measurements giving very different results. It's not a cirrus
thing or the like because it happens all the time and the pattern is : one
observation bright , the following 0.2 or even 0.3 mag. fainter and so on.
The big problem with this is that when there is a single observation per
night... how can we believe in its value? It becomes more a  matter of faith
than anything else.... Something must be happening and maybe it can be
corrected.

I attach an even worse example I found during my eclipsing binaries studies.
It is a small gif so I hope noone bothers with the attachment.

On the other hand, there are other stars (at the same magnitude) where the
data can be used. So the problem is even more difficult to understand.

Cheers,
Sebastian.

GSC_3319_0399.gif