[AZ-Observing] Re: Important Psyche Occultation Wed. night Oct. 23/24, s.w. USA
- From: Brian Skiff <bas@xxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Sun, 20 Oct 2019 07:49:03 -0700
On Sun, 2019-10-20 at 05:18 -0400, dunham@xxxxxxxxxxxxx wrote:
There’s uncertainty in the star’s magnitude; 10.2 is from Gaia. But the GSC
says 12.4 and APASS gives the V-magnitude as 11.4 with B 13.0. The large B-V
indicates a red star,
The photometry is in fact pretty well-defined. The
magnitude 10.2 from GAIA2 is the GAIA2 'G' magnitude, which
will be quite a bit brighter than a standard V magnitude.
The GAIA2 'BP' magnitude, which is somewhat blueward of
standard V, is 11.8; GAIA2 'RP', not far from Cousins I,
is 9.0.
The star is indeed a small-amplitude red variable,
with mean V mag about 11.5, as shown very nicely by the
ASAS-3 lightcurve covering eight seasons.
The star also appears in the new SkyMapper survey
catalogue with the following Sloan magnitudes: g = 11.9,
r = 11.0, i = 9.6. As can be seen, if you use a camera
detector that is sensitive toward the far-red, the star
will be quite a bit brighter.
\Brian
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