Quote:
Originally Posted by Ian Robinson
I expect unless you use fancy relay lenses or use much bigger secondarys than usual , that vigetting and back focus with binonewts would be a big issue.
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No its not an issue at all. You generally use diagonal one size larger than normal. By using compact star diagonals there is no extra vignetting. My upcoming 14" F4.6 binos are using 3.1" diagonals which are only about a 22% obstruction.
The `reverse' binocular Newt design ( as JMI have called it) is by far the most common and simplist to make. Anybody wanting to make a success of the project would be wise to copy successful examples.
William Herschel was the first to build a Newtonian binocular with 6" mirrors of his standard F13 focal ratio.