RE: [APML] Televue 101 Star test

["Richard Klappal" <klappal@xnet.com>]

One of the biggest problems with doing true star tests is that the 'inside
of focus' part of the test usually focuses on air turbulence in the upper
atmosphere.  Under bad conditions the rings will appear boiling; better
conditions can make them seem mushy. Its rare to get realy good images
outside of a lab.

-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
Behalf Of Michael
Sent: Sunday, November 10, 2002 02:23
To: astro-photo@seds.org
Subject: [APML] Televue 101 Star test


Hi all. I know this is an astro-photo mail list, but I wonder if you can
answer a star testing question. My friend and I tested his Televue 101 last
nite on Vega with a 2X Powermate, the lens we used escapes me. But, we saw a
perfect airy disk and about 5 or 6 perfect rings, but moving to the other
side of focus showed very fuzzy rings. I think the good rings were outside
focus and the fuzzy
ones were inside focus, but I could be wrong. I'm trying to read "Star
Testing Astronomical Telescopes" by Suiter, but it's a hard read. Does
anyone know what either scenario means as far as the condition of the optics
is concerned? Regards


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