wpo - a small tubeless reflector with hardhat mount

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These photos show a small tubeless 10cm aperture f/7 reflector built in the 1990's.  It uses plastic drainage fittings [from B&Q etc] to hold the primary mirror, a length of lightweight ali rod to separate the optics and a short section of ali tube to serve a dual role of supporting the secondary flat and screening skylight from the eyepiece.  The eyepiece drawer tube is a section of plastic plumbing araldited to secondary holder - which being circular, minimises diffraction effects around objects viewed.  The secondary adjustment screws for rotation and tilt shown in the centre photo below.

My hardhat was seconded as a mount!  Two ali brackets eitherside of the mirror cell wedge into the hardhat which rides on a three-pointed "crown" made from a piece of plastic drain pipe.   A small lead weight behind the mirror cell ensured balance and the whole system was remarkable smooth, stable and easy to use.  [A similar shaped spherical support is used for the Edmund Astroscan.]  The card mask, with small 4cm off-axis hole, used for direct solar observation with full aperture solar filters.

Note: I've successfully used ply, plastic and aluminium for several decades of telescope making. These materials are easily worked and shaped with hand tools and electric jigsaw and all may be directly tapped with steel screws via slightly undersized pilot holes.  Ply should be taped to minimise splintering when sawing.

Maurice Gavin - Worcester Park Observatory - Surrey - UK.

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images & text copyright-Maurice Gavin-Mar 1994/2004