From: Alex Conley (aconley@panisse.lbl.gov)
Date: Sun Apr 14 2002 - 21:37:41 PDT
I have redone the finding charts for the objects
S02 - 25,24,16,7,44,26,01,30,49,46
We were having some problems with saturated stars earlier, which lead
to incorrect position measurements, and hence bad offsets. Doh!
The current version of the finding chart software lets you look at
surface plots of every potential offset star to detect saturation
(and galaxies).
In order to avoid confusion, I have blown away all other finding charts
for these objects from the finding chart webpage. Any copies you may
have of these finding charts that have not been downloaded since I last
talked to Saul should be burned. If you don't know when this was,
then assume that the finding chart you have is bad, bad, bad.
The bad news is that the offset stars are unavoidably dimmer. On many
images saturation starts at 19th magnitude. Since this is the maximum
acceptable offset magnitude (or so I am told) you can see we have a
problem. There are some exceptions to this rule -- S025 seems to have
a 18.35 mag non-saturated star. This makes me question the quality of
our zeropoints all the more. In any case, for most objects you are
probably stuck using the image the sky, the slit, and then offset method
even with the new finding charts. You will have to decide for yourselves
though. Or maybe Quimby's magic method will save the day.
Attached is a file with the coordinates of all of the offset stars
for the above candidates. Enjoy! The file is located at
http://panisse.lbl.gov/followup/charts/spring_2002/refstars.txt
and I will be updating it as I finish more charts.
I started trying to make finding charts for the missing scp/subaru
objects (on SS4), but it is proving to not be so easy. In other words,
don't count on finding charts for those objects any time soon.
Alex
This archive was generated by hypermail 2.1.4 : Sun Apr 14 2002 - 21:41:40 PDT