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[vsnet-chat 6401] Errors in the newly released AAVSO charts for eta Carinae



The AAVSO has asked for observations on eta Car and rho Cas.

The following announced charts (
http://vsnet.aavso.org/charts/CAR/ETA_CAR/ETACAR-A.GIF, ETACAR-B.GIF,
ETACAR-E.GIF) suffer from terrible mistakes:

In the "a" chart for eta Carinae, the star labeled as "59" next to T Carinae
is the spectacular variable AG Carinae!!!
The "59" value is the actual magnitude of the non-variable star T Car.

BUT...... in the "b" chart the 8.68 mag. star HD 94664 is marked as T
Carinae!!!!!!! This time "593" is the real T Car (shown as comparison star)
and AG Car is not marked in any way.

Please, keep trying, maybe next time you can spot one or two stars
correctly......

Int he "b" chart there are also magnitudes to 2 decimal places that are not
of good quality (i.e 865 = 8.58, don't trust Tycho when there's plenty of
PEP from the ground), including a double star (776, but AB (14")= 7.71).

For CCD photometry, the "e" chart show two stars: 73 (HD 93403) = 7.30 that
is actually 7.27 (who said Tycho-2 is the better choice for bright stars?
See Hipparcos and GCPD data) and 93 (HD 93343), that turns out to be a mess:
In Reed (1998) you can see the following notes: "Doble/SB/Multiple"
In the TIC catalogue, two stars are described:

1)  GSC 8626 2018 - Pos: 10 45 13.043 -59 44 19.98 - B mag. 9.60
2)  GSC 8626 2838 - Pos: 10 45 12.389 -59 44 26.18 - B mag. 9.80

I couldn't find the second star in other catalogues and UCAC1 and USNO-B1.0
return only one entry.
There are dozens of PEP measures in the GCPD and VizieR and they go from
9.17 to 9.64 (generally around V= 9.58) and B-V 0.24-0.35 (redder when
brighter).
It is also a ROSAT source.
An O8V star that seems to be variable or contaminated by a companion.

See the charts at my website for eta and AG Carinae as a reference:

ETA CARINAE:
http://ar.geocities.com/varsao/Carta_eta_Car.htm
AG CARINAE:
http://ar.geocities.com/varsao/Carta_HD_95687.htm

Regards,
Sebastian.


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