[AZ-Observing] Re: Seeing Conditions During Monsoon

IMHO, Steve is on the right track, here. (As are Derrick, AJ, and Tom 
with their earlier remarks.....)

There is some useful information on the Rose City Astronomers web pages 
-- they have a Weather SIG that is trying to make some sense of 
this....Categorizing the effects as macro, meso, or micro scale, 
depending upon where the effects originate in the atmosphere.
http://www.rca-omsi.org/seeing.htm

The Pickering Scale establishes a range of numeric values to 
characterize the seeing based upon the appearance of the Airy disk 
during an observing session.  Here's a couple of good on-line resources 
about seeing and so forth:
http://celestialwonders.com/articles/seeing/
http://www.telescope-optics.net/induced.htm
http://www.aajonahfish.com/Articles/Seeing.htm
 
Observers should review the useful and valuable article by Dr. A.E. 
Douglass (founder of the Steward Observatory in Tucson, and better known 
for foundation of the study of dendochronology, tree rings) on 
"Atmosphere and the Observer", which can be found in Amateur Telescope 
Making (ATM) Book Two, p. 585 (old series).  While an assistant to 
Perceival Lowell, he observed and sketched the airflow shadows (known 
later as schlieren patterns) seen with the eyepiece pulled back, so as 
to focus on various layers in the atmosphere.  He did not have knowledge 
of the jet stream or weather balloon survey data at that time (1897), of 
course, but his descriptions go a long ways towards explaining much of 
the phenomena.  (This information has basically been ignored by most 
modern observers...)

Observers today can do the same, from their own backyards, and learn a 
good deal about what is happening overhead....You can judge the size and 
speed of the air cells passing across your telescope aperture. The new, 
sensitive CCD cameras (and inexpensive web cams) make it possible to 
record the shadows of the flow patterns for study and demonstration to 
others....

Gene Lucas
(17250)

Steve Coe wrote:

>AJ, Brian, et al;
>I do remember hearing that the cells that effect seeing the most are not
>high in the atmosphere, but actually are only 10 feet or so above your =
>head. I have no idea where I heard that, it is information from many years ago 
>=
>and I just don't remember the source, sorry.
>But, our experiment while the star was being occulted by Saturn certainly
>seems to provide information that would support the "close by" theory of
>fast seeing.  Maybe there are two effects, one close by and one far overhead.
>Of course, none of this matters when the storm is overhead raining on your 
>telescope;-)
>Clear Skies to us all;
>Steve Coe
>  
>
[earlier interesting stuff snipped, so as not to offend the NET NANNY!!! 
- GL]


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