Allan Rahill of the Canadaian Meterological Center has created a numerical forecast model for astronomical seeing ...
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Bruce L. Gary
brucelgary
Aug 28, 2002 6:36 am
As a CCD user I feel the need for a method of measuring "atmospheric seeing" that is specifically directed to what a CCD records after a well-guided long...
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Attilla Danko
attilladanko
Aug 28, 2002 7:03 am
Not being a CCD photographer I dont know of one. But I know just enought about the instrumentation to speculate that if one turned off one's drive, exposed for...
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Allan Rahill
allan_rahill
Aug 28, 2002 1:43 pm
Hi Gary... Actually, I am trying to find the best way to corrolate the seeing forecast to CCD applications. Lately, I did only 3 sessions of CCD to look at the...
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Attilla Danko
attilladanko
Aug 28, 2002 4:43 pm
... Isnt it more complicated that that? Peridoic error in the drive would introduce a regular woble with a perioud of a minute or two. Atmosphereic refraction...
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brucelgary
Aug 28, 2002 4:47 pm
Attila and Allan, Thanks to both of you for excellent suggestions. Turning off the sidereal drive and registering a star track on the CCD strikes me as a ...
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mann9471
Aug 28, 2002 8:57 pm
Are the current seeing forecasts at clear sky clocks using sounding data from balloon radiosondes? I am just starting off into the world of "astronomic seeing"...
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Bruce L. Gary
brucelgary
Aug 28, 2002 9:58 pm
Concerning the "atmospheric seeing" forecast challenge: An observer's experience of "atmospheric seeing" may depend on the telescope altitude above ground....
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attilladanko
Aug 28, 2002 10:03 pm
... wrote: > ... as they ... tropopause ... I hope Allan replies in detail. But I know a little of how he does it. His own data, 541 observations of seeing...
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Allan Rahill
allan_rahill
Aug 29, 2002 1:47 am
... can mesure the average amplitude of this wave to measure CCD >seeing. Isnt it more complicated that that? Peridoic error in the drive would introduce a...
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Allan Rahill
allan_rahill
Aug 29, 2002 1:57 am
Thanks Bruce for your ''think out loud''. I always enjoy reading your thoughts and these express my thoughts as well. I agree with most of the item you...
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Allan Rahill
allan_rahill
Aug 29, 2002 2:08 am
Shannon, Yes the baloon soundings are used in the analysis. When I started with my study, I had the same question than you regarding the lifted and richardson...
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Allan Rahill
allan_rahill
Aug 29, 2002 2:12 am
Attilla is a good student, Indeed, the corrolations is higher with low level wind than the tropopause. It doesn't mean the tropopause doesn't create seeing,...
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attilladanko
Aug 29, 2002 2:47 am
I've created a couple of folders for links. I've added all of the astronomy-specific weather sites that I know. http://makeashorterlink.com/?Q56A353A1 Please...
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attilladanko
Aug 29, 2002 3:03 am
I sometimes get asked for long term cloud cover stats, like the number of clear hours per month, for some specific latitude and longitude. (Seems like...
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Bruce L. Gary
brucelgary
Aug 29, 2002 3:35 am
I have a "sunshine map" from an old geography book (that my daughter used as a coloring book), and I'll attach a copy of it here. I don't know if image...
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Bruce L. Gary
brucelgary
Aug 29, 2002 3:50 am
Here's a link to a "sunshine map" of the United States (that I just created, since my attachment on a previous posting got stripped). Sorry Canada isn't...
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Attilla Danko
attilladanko
Aug 29, 2002 4:07 am
Thanks Your charts pretty much confirm what I thought: I live in a cloudy spot I think it's very odd that sunshine/cloudyness data isnt more common on the web....
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attilladanko
Aug 29, 2002 2:26 pm
I'd like to put the answer to this on in a FAQ: Q: If water vapor is a clear colorless gas, why does the presence of water vapour, without droplets, reduce ...
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Ling,Alister [Edm]
alister.ling@...
Aug 29, 2002 3:36 pm
It is very important NOT to neglect tropopause effects, as Allan indicates. There have been several occasions in the past where I'm sitting in the middle of a...
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Allan Rahill
allan_rahill
Aug 29, 2002 7:46 pm
This is the way I always explained the effect of moisture to reduce transparency, scattering. Moisture also increase somewhat the extinction. I have to add,...
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Allan Rahill
allan_rahill
Aug 29, 2002 7:52 pm
It is a pleasure to see you joining the group Alister. Regarding cases you mention with upper ridge sitting over alberta, how bad was the seeing when the...
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jdb_mars
Aug 30, 2002 10:30 am
Actually the boundary layer is the last 12 meters to the surface. At least it was the last time I studied micrometeorology. DustyMars ... tropopause. ... me...
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Bemusabord@...
Bemusabord
Aug 30, 2002 12:45 pm
We were at the Black Forest Star Party (Cherry Springs State Park, PA.) in the wake of 9/11 (it was held just a few days later, when there were no planes...
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jdb_mars
Aug 30, 2002 1:50 pm
Some good stories (articles) on "astronomical seeing" can be found at: http://www.cmc.ec.gc.ca/cmc/htmls/seeing_e.html "How to Predict Seeing," By Eric J....
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polakis2000
Aug 30, 2002 2:35 pm
I can speak only from the limited perspective of an Arizona observer. I'd say that aircraft contrails have no significant effect on sky conditions, at least on...
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Allan Rahill
allan_rahill
Aug 30, 2002 5:31 pm
In the world of meteorology, the boundary layer is usually below 3000 feet (1000 meters). It is the layer where the airmass creates an inversion during the...
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Allan Rahill
allan_rahill
Aug 30, 2002 5:38 pm
No, unless you live nearby Chicago or other major airports where airplane turns around before landing. When there is a lot of moisture at the tropopause, in...
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jdb_mars
Aug 30, 2002 11:26 pm
Well, according to the book I usually reference these things from: Descriptive Micrometeorology, by R.E. Munn, Advanced in Geophysics, supplement 1, 1966....
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Ling,Alister [Edm]
alister.ling@...
Aug 30, 2002 11:58 pm
Just a brief answer... glad to be on the list! ... Subject: RE: [AstronomyWeather] Re: Ground effect on "seeing" ... you ... moved ... Oh, it went from 4 (very...
