[AZ-Observing] Re: Seeing Conditions at a Dark Site

     A lot of the poor seeing we see in Arizona is due to cool air 
drainage from higher areas to lower ones.  In the basin-&-range areas
of the southern half of the state, this really reduces the seeing
quality at many of the sites folks use.  Even on Anderson Mesa, the
very slight cool air drainage off the mesa into the lake bed below 
limits seeing quality on most nights.  So you wanna at a place where
there isn't this effect happening.  I think Tom Polakis, Jeff Mekeff,
and others have looked into this in the area south and east of Tucson
in a fairly general way.

>>  ...if the wind is blowing hard then the seeing is never good...

     Try standing on the outcrop near the WIYN telescope on Kitt Peak
on a typical springtime night:  it'll be windy enough you can lean
into it, but the seeing will be 0".3.  Have Tom Polakis tell you about
one of the nights we were at Las Campanas in Chile where we had to 
pull the roll-off roof of the building we were in up to prevent the
teelscopes getting buffeted---very turbulent and windy, but near-perfect
seeing.  It's not the wind per se, or the turbulence, but instead 
uniformity of temperatures that matters for local seeing.
     Upper-air turbulence, which Steve Coe alluded to, can be a problem,
but can happen pretty much any time of year.  Although you can't do
anything about it, it _is_ fairly accurately predictable:

http://www-frd.fsl.noaa.gov/mab/tke/tke_new.cgi

This won't predict good seeing, but does an excellent job for bad seeing,
and you can have the advice 12 hours in advance.  I've been choosing the
least extrapolative map time, and selecting 12000 feet as the altitude
to look at.  Try it before some observing nights and see how it perfoms
for you.  I think Frank Kraljic has been using this as an aid for 
planetary observing, and perhaps he can report on how useful it is.

\Brian
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