[AZ-Observing] Re: Photometric Night Definition
- From: Brian Skiff <bas@xxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Mon, 12 Feb 2007 20:10:38 -0700 (MST)
As long as the extinction is stable, then in principle it can
be arbitrarily high and the night still be called 'photometric'.
Values up to around 0.5 mag per airmass are not uncommon at humid,
low-altitude sites. Outside of volcanic events the normal seasonal
range in Flagstaff is from about 0.11 (i.e. just gaseous air plus
ozone with no extra due to aerosols) to about 0.20 or so during
last spring from windblown dust plus things like Asian dust episodes
(which we haven't had in a few years). The baseline extinction is
a function only of altitude, so can predicted for any site.
\Brian
--
See message header for info on list archives or unsubscribing, and please
send personal replies to the author, not the list.
Other related posts:
