The Focuser


Making a 4.25 Inch Dobsonian Reflector Telescope



          For anything but the most frugal telescope builder, I recommend buying a focuser.    A good 1.25 inch focuser will cost maybe $30.   A 2 inch probably starts around $50 and up, but if you are building a large scope, it will be worth it.   For this small project I came across a couple cardboard tubes that mated perfectly and held 0.965 inch eyepieces with a little tape.    Much more effort went into making adapter for the tube.    For larger tubes I built a jig that worked with a band saw.   For the 5 inch tube, the band saw blade wouldn't turn enough so I ended up using a router on a long square piece of wood to get the right curve.  The four machine screws are held down with nuts.  



Disassembled Parts View




Adapter Top View



Adapter Bottom View



Adapter Side View