Pickering Seeing Scale
Anyone know how to translate the Pickering scale for larger or smaller scopes? It was done with a 5" refractor.
It's difficult to see an airy disk and rings in a Nexstar11, but easily done with my TV76 (3" refractor).
After a week of the skies at 2-3 on the scale because of the jet stream, tonight it was much better. At about 40 degrees elevation the seeing was between 6 and 7. At zenith, it matched up with a 9 on the scale. But, that's with a 3" scope. So, I'm curious as to how to relate that to a 5" scope.
Sure hope it stays like this for the Sentinel-Schwaar Memorial Star Stare Friday and Saturday!
Clear skies,
Jim
The Pickering Seeing Scale
Started by
Guest_**DONOTDELETE**_*
, Apr 25 2003 02:32 AM
1 reply to this topic
#2
Tom T
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Posted 25 April 2003 - 09:22 AM
Hey Jim,
While I'm not aware of a set formula to translate the pickering scale to different apertures, from what I understand those results (on the page you referenced) are pretty typical for scopes up to 8 inches in diameter. Little modification is required. For say a 16" scope tho - then I understand they are quite different. There was some discussion a while back to use abberator to produce another set for 16+, but I take it that never happened? I haven't seen it, but then I haven't spent much time with scopes that large in any case.
While the pickering scale is a handy quick referance, by it's very nature, it's not all that exact. If you really want to know what your seeing is (to the arcsecond), you might try this list of double stars compiled by Brian Skiff for just that purpose:
ftp://ftp.lowell.edu/pub/bas/dbls.fil
ADS refers to the Aitken Double Star Catalog.
Tom T.
While I'm not aware of a set formula to translate the pickering scale to different apertures, from what I understand those results (on the page you referenced) are pretty typical for scopes up to 8 inches in diameter. Little modification is required. For say a 16" scope tho - then I understand they are quite different. There was some discussion a while back to use abberator to produce another set for 16+, but I take it that never happened? I haven't seen it, but then I haven't spent much time with scopes that large in any case.
While the pickering scale is a handy quick referance, by it's very nature, it's not all that exact. If you really want to know what your seeing is (to the arcsecond), you might try this list of double stars compiled by Brian Skiff for just that purpose:
ftp://ftp.lowell.edu/pub/bas/dbls.fil
ADS refers to the Aitken Double Star Catalog.
Tom T.
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