How can flexure be eliminated?
My main worry at the outset of design has always been flexure, because it can so easily corrupt convergence. All telescopes probably flex to some degree an unavoidable deflection due to gravity but it usually goes unnoticed. With a binocular telescope, even slight flexure can knock out convergence and prevent image fusion which is very noticeable. Flexure is a bigger problem in binoculars since each side may bend differently due to differences in weight or construction. This places unusual demands on the mount’s construction: slight flexure-caused deviations from the parallel position may cause image shift and detectable loss of fusion. To my gratification, once binocular parallelism was achieved on my 12″, it remained aligned from the zenith to within 10 to 15 of the horizon. On my 22″, I added an x-y linear stage at the top end that allows tuning of binocular alignment while looking through the eyepieces. This permits the use of higher powers, where misalignment of the two images is
