[vsnet-chat 4213] Re: Omega CMa comparison stars

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

> I'm wondering which stars are being used as comparisons for
> Omega CMa? Southern CMa seems to be littered with bright
> low-amplitude variables, so I had considered including this
> region in BVfSO. But I gave up, frustrated by the apparent
> shortage of suitable comparison stars.
>
> So what comparisons are the various Omega CMa observers
> using?
>
> I had a quick eyeball of Omega CMa last night and earlier
> tonight, and both times it looked to be of equal magnitude
> to Delta Col (3.85V).
>
>

Hi, Fraser:
                Although most of the stars in the region are slightly
variable I use to make two or three estimates with different comparison
stars to eliminate possible errors and there has been no problem.
Omega CMa is at 3.9 and the comparison stars I use are:

k Puppis, a Be variable with near 0.05 mag. of amplitude. V= 3.82,
B-V= -0.16
3 Puppis, an A supergiant only suspected to vary in V. V= 3.96, B-V=  0.18
and 11 Puppis, an F8 bright giant. V= 4.20, B-V= 0.72.

Delta Col V= 3.84, B-V= 0.86 is a little too far away and too orange. k Pup
is the best one for position and
color.

Anyway I think omega CMa should be included in a new version of BVfSO called
NEVfSO, you know why...:-)

Cheers,
Sebastian.


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