[ATM] Re : Rating mirrors, example

["Benoit Schillings" <benoit.schillings@openwave.com>]

Jeff,

On the mirror rating and how a double star looks under good seeing
Here is an image of Castor (alpha Gemini) which is about the same
spacing
As the components of epsilon lyra, this is with an 18 inch (Galaxy
optics mirror)
At F/30 (using a barlow).

This is under very good seeing, but it shows how small the diffraction
spot
Really is compared to the 3 arcsec or so spacing, I guess visually, this
would be
A magnification of 2500x or so if your screen is about 16 inches from
your face.

 http://www.astrosurf.com/benoit/castor_0.3arcsecfwhm.jpg


-- benoit
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