[Aavso-photometry] Stellar Project #2

[arne]

A couple of people have mentioned that they couldn't find V1412 Aql
using VSP.  This is correct.  V1412 Aql is also known as G 24-9,
a high proper motion white dwarf (the 9th star in the 24th list of
high proper motion objects by Henry Giclas, an astronomer who was
at Lowell Observatory).  The proper motion is 250 mas/year
to the west and 578 mas/year to the south.  This high proper motion
causes some interesting problems in identification for this
crowded field.  Simbad gives positions as epoch 2000 and equinox 2000,
and we are now at epoch 2009. This means the position given in Simbad
is now about 5arcsec different than what the SRO image shows.
The GCVS just gives precessed coordinates from the discovery paper
(or whatever paper that gave the best coordinates)
and as such is even further off - they list the positional information
as "epoch 2000" but this is wrong.  Their position differs from SRO
by over half an arcminute.  And of course, if you compare against
one of the photographic surveys, like POSS-1, where the plates were
taken in the 1950's and act as a "snapshot" of that time, the position
of V1412 Aql is even more radically different.  Proper motion in
general will cause lots of identification problems for many stars
in the future if you don't take it into account. V1412 Aql itself
is star#02 in the accompanying text file, currently at

20:13:55.53  +06:42:39.8  equinox J2000; epoch 2008.9

Arne