APASS quality checking
Arne Henden
ftp://ftp.aavso.org/public/calib/apass_dr0.zip
this is an 11MB file that decompresses to 64MB, plain ascii text. It
consists
of 800 square degrees of sky covered by APASS at least twice at B and
V.
What would be useful is some testing. Find matches with Landolt, or
even
Sonoita, and see where the errors reside. How poor is the astrometry;
does
it vary with declination or magnitude? How well do the V, B, and (B-
V)
track known values? Any obvious systematics?
The observations should be good from V=10 to V=16.5 or so; anything
brighter than V=10 is likely to be saturated. Raw astrometry sez the
positions are good to 1arcsec or so. However, I note that Seqplot
shows
double stars for many bright objects up at +80, so there is either
some bug
in my code or in Seqplot.
I'll do the same thing when I've transformed the g'r'i' measures, as
one very
useful exercise will be to see how well we can transform BVgri into
BVRcIc.
Arne
Michael Koppelman
To everyone else -- this is a huge opportunity for a lot of reasons.
You can a first look at brand new data. You get familiar with the
system's capabilities and data formats. You can provide assistance by
testing the data against other data sets. The list goes on. Don't pass
this up! I'm hoping this section can be first in line for data from
APASS and to accomplish that we need to show that we are worth it!
Dive in!
M!
On Feb 11, 6:53 am, Arne Henden <ahen...@gmail.com> wrote:
> I've uploaded toftp://ftp.aavso.org/public/calib/apass_dr0.zip
Doug Welch
Just a note to all - as someone who downloaded this file - the very last
line in the file gives the identification of the columns.
-Doug
Doug Welch
Folks,
The distribution of RA and Dec in the apass_dr0.txt file can be found at:
http://crocus.physics.mcmaster.ca/apass_dr0.jpg
Produced using TOPCAT from http://www.star.bris.ac.uk/~mbt/topcat/
Cheers,
Doug