Re: [ATM] Ghost image

["John Sherman" <atmer@johnspics.com>]

Hi Dale,


>I was surprised one time to find it was my glasses
> reflecting or the second image from my bifocals.


Ya, I heard that some observers had trouble with bi- and progressive-focus 
eyeglasses. So I took a different route for my observing glasses. My left 
eye has my distance prescription, as that is the eye I normally use for 
observing. I observe bright objects with my right eye so that they don't 
interfere with the dark-adaptation of my left eye. The right eye of my 
astro-glasses has my reading prescription in them. That way I can read 
charts and books easily in dim light.

The only time the strange glasses are a problem is when there are bright 
objects against a dark background (such as stars in a dark sky, or lights on 
cars at night). In those cases I easily see both the focused image and the 
fuzzy image. But most of the time my brain easily ignores the eye with the 
fuzzy image, and uses the sharp image from the other eye, and so I see 
things in focus whether they are close or far.

It is interesting that the reading glass prescription for my right eye blurs 
the non-telescopic view of stars and planets into the same sized blur as my 
naked eye does. It is more interesting that if I focus the scope for my left 
eye (with it's distance prescription), I only have to make a very small 
adjustment to focus for my right eye (with the reading prescription).

John






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