Jan Owen posted:

On nights of exceptional seeing conditions, why not fully dark adapt

your

eyes and see just how faint your scope can go? I have posted an image
which labels the stars in the immediate area of Messier 57 with their
magnitudes on my website. My 12.5 inch dob has revealed the 14.7

magnitude

star and using averted vision I can sometimes convince myself that the
neighboring 15.3 magnitude star is hinting at its presence.

To see the image, go to http://home.earthlink.net/~martinhowell and

click

on "Other stuff"


Martin


...and the central star???

-- Jan Owen

The Central star is about magnitude 15.0, but it takes high power and *very*
stable seeing to pick it up. Seeing variations can make its tiny Airy disk
blend into the glow in the interior of the ring. It tends to vanish unless
the seeing is rock-solid, and often is observed to 'flash' on and off with
seeing variations. I have seen it in a NexStar 9.25GPS, but it was *very*
marginal. It should be not terribly difficult in a 12 inch, but again, if the
seeing isn't very good, it won't be visible in any aperture. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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