[ATM] Super compact Houghton camera

["vladimir sacek" <vla@toast.net>]

These past couple of days I've been playing with the Houghton corrector. Incidentally, I realized that by putting the corrector - the type consisting of a pair of plano-concave and plano-convex element - half way between the mirror and the focal plane (single-mirror arrangement) the system becomes aplantic, with the field practically flat and with relatively low astigmatism. In fact, both astigmatism and chromatism are comparable to that of the Wright camera, only in an all-spherical system.

What makes me curious is that I never heard of this type of camera before. If it is about as good performance-wise as the Wright, much easier to build and twice as compact, why isn't it at least mentioned here and there? I've put more details about the camera at:

http://www.telescope-optics.net/Houghton.htm

Vlad
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