Message from Jim Bedient

[Tom Droege <tdroege@veriomail.com>]

The message below from Jim Bedient came to me as it bounced to the list.

Hello TASS-listers,
I have a question about TASS tenxcat data that I'm hoping someone can answer.
I am researching a variable star that I noted while blinking Stardial
images. I figured out (so I thought) which star it is, looked it up in
VizieR, and was happy to see (1) it's not catalogued anywhere as a
variable, and (2) there were some observations (16 V-band estimates) in
the tenxcat that confirmed the variability. I downloaded many megabytes of
Stardial FITS images, and came up with 293 differential magnitudes spread
over six seasons, which yielded an nice light curve and a set of elements.
The tenxcat observations fit just perfectly with the light curve.
So far, so good. But now some problems have arisen over exactly which star
is which. I looked at a couple of DSS images from both the first and
second generation plates, and it appears that the variable is actually
another nearby star, USNO A2.0 0825-15411768. Now, the problem is: GSC
5148-446 has the tenxcat observations associated with it, and those
observations fall nicely in phase with the Stardial observations. However,
USNO A2.0 0825-15411768, which appears to be variable in two DSS images,
does not have any tenxcat observations associated with it - but the plot
thickens. There is a tenxcat listing, TASS J192035.3-035756, which lies
about 8 arcsec southeast of the USNO star. The observations associated
with this listing ALSO fall in phase with both my Stardial observations AND
the other nearby tenxcat listing (GSC 5148-446. To ice the cake, there is
an IRAS point source listed just 12 arcsec west-southwest of the USNO star.
The USNO star is just on the edge of the IRAS error ellipse.
I interpret all this to indicate that the USNO star is the variable, and
the the two tenxcat listings should really be one and the same, and the
association with GSC 5148-446 is spurious. The IRAS source confirms the
approximate position of the mira.
Questions are:
In the tenxcat observations for the two objects, there are two that are
from the same night:
Partial listing from the GSC star:
TASS light curve SQL query
# Name 5138-00446 TASS_ID 1853356 coords ( 290.1524 , -3.9722 )

# Filter JD-2,450,000 magnitude
V 719.5300 11.736 raw
Partial listing from the USNO star:
# Name TASS J192035.3-035756 TASS_ID 1853192 coords ( 290.1471 ,
-3.9657 )

# Filter JD-2,450,000 magnitude
V 719.5300 11.226
Are these (1) the same observation, one corrected and the other not ("raw")
or (2), observations from different cameras?
The bottom line question, I guess, remains: is it possible that these two
tenxcat sources ARE one and the same?
Thanks for any light you can shed on this.
Jim Bedient

=======================
James Bedient
bedient@hawaii.rr.com
Meteor Group Hawaii
http://www.meteor-group.com