seeing

[aah@nofs.navy.mil]

Chris wrote:
>What you are saying is the optical blur is far worse than the
>blur caused by seeing?  Let's assume I have a poor site is this
>still true.
  Yep.  The 28 arcsec images (fwhm) are almost all optics-related.  A
Spring-time thread decided (I think) that these lenses are poor-fair
in optical quality, and the resolution is about 60 lines/mm.  High-quality
lenses (Nikon/Canon) are more like 200 lines/mm, which would give sub-pixel
resolution, but are 10-100x more costly.
  The worst seeing I've ever tried to observe through was about 10arcsec.
It takes a really, really bad site to have typical seeing that bad.  Most
lowland amateur sites are in the 3-5arcsec range.  All of these figures are
far below the 28arcsec TASS images, which is why I say we are essentially
in the pre-fix HST era, and should be able to model the aberrations in an
analytic fashion pretty well.
Arne