Polarization Standards for IRCAL
For calibration you should also observe an unpolarized standard star.
I've been using the list on
UKIRT web page but any nearby star
should be unpolarized (i.e. no interstellar polarization). The UKIRT
list is in 1950 coords and they're all high proper motion stars, so
look up the new coords from SIMBAD or you can waste ten minutes
trying to find a star in completely the wrong spot. The observation of
the unpolarized standard star should be unsaturated - and can actually
be done open loop since we're just doing aperture photometry on it.
There are also Serkowski polarized standards available on the same web
page. I haven't found these to be all that useful for our purposes
since most were measured with very large apertures (20" or larger) and
it's often hard to compare the data to our spatially resolved
Here is a Lick-format
target list containing these stars.
This page last updated by Marshall on 2005-12-08