[AZ-Observing] Re: Quick look at gamma Vir in the Lowell Clark

Silly me, working on my SAC 110 Best doubles last week, which lists Porrima
as 5" (piece of cake, but dated 1990), I finally tried 100x/inch with my
80mm in only wavy Airy disks and thought I must be looking at the wrong
star. I checked the column in my Tirion/Skiff Bright Star Atlas, and went
well no wonder, it's listed 1.8" (2000) with a footnote about its rapid
motion. Guess I won't get that award til 2100, a little more time than I
wanted to invest.

Jack

>      I took advantage of a lull between tourist groups this evening
> (May 25/26) to check on gamma Vir in the Lowell Clark.  I was helped
> by the Clark 'friend' John DeDecker of the Lowell tour staff.  With an
> approaching deformation zone or weak trough, the seeing was about 1".5,
> mainly expressed in the smaller apertures as very jumpy Airy discs.
> We viewed at several small apertures down to the minimum of the iris,
> which is 15cm = 6-inches.  The eyepiece was a 22mm Panoptic, which with
the
> long focal length of the refractor (9776mm) gives nominally 445x.
>      In the smallest aperture, gamma Vir was merely elongated in what's
> termed a 'breadloaf'.  With better seeing I would expect it to appear
> as a figure-8 at the separation that was mentioned in the recent 'amastro'
> post.  At 20cm/8-inches the Airy discs were just touching as expected.
> By the time we worked up to 30cm/12-inches, the image blur was too
> washed out to see much of anything.
>
> \Brian


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