(SOLD!) V-Block Filter 2" Removes Violet Fringe from Refractors without reducing image brightness. Improves picture and focus. Used 3 times. Also works great in a threaded diagonal. (Selling my refractor, so must sell this filter.) Original box and filter case included.
$69, including 2-3 shipping CONUS.
PayPal preferred. Money Order acceptable. No personal checks.
Improves the Clarity of Bright Objects in Refractors
With refractors, it's normal to see some purple fringing or halos around bright objects such as the planets, Moon, and bright stars. Such false color, or chromatic aberration, results from the inability of a standard two-element ("achromatic") lens assembly to focus all wavelengths of light to a single point. The effect is particularly pronounced at higher powers. The V-Block removes this color, while improving the normal color, and focus.