Dobsonian Telescope

    I designed this telescope with Matthew Kleid in the Winter of 2004-2005. It uses an 8 inch parabolic mirror with a 48 inch focal length. Hopefully I will post some images that I took with the telescope once I get it collimated again.

This is the entire telescope. The tube is 0.25 in. cardboard with a 10 in. inner diameter. The mount has two degrees of freedom and is made of plywood and particle board. The rubber wheels on the side allow for rotation along the azimuth without slipping. The entire body rotates around the polar axis about a large steel pin. An acrylic sheet is fixed to the base to reduce friction during rotation.

This is a top down view of the telescope. The mirror spider on the top can be recentered (2 DOF) and the small angled mirror it holds can be adjusted (3 DOF). The large reflector at the bottom can be recentered (2 DOF) and can be pitched (2 DOF). Collimation can get pretty tricky when tuning all 9 parameters.

This is the focussing unit that I designed and built. The fixed portion has a arc face to better mate with the tube as it is glued in place. The mobile stage rides on 4 threaded rods. One rod is mounted in a bearing on the fixed portion and is engaged in a threaded section on the stage. Thus the unit can be focussed by turning this one screw.