Homemade Combination Tube
                                                          

Collimation Eyepiece (Combination Tube)

I needed a collimation eyepiece and was about to order one, then I discovered Nils Olof Carlin's Collimating a Newtonian Telescope DIY Section and saw how simple it was to  construct my own. I made a combination tube, which functions both as a Cheshire eyepiece and simple sight tube with crosshairs.  Total fabrication time was about an hour and all the parts were free, saving me about $45. I just followed the instructions on Nils' website, which is the best single source of information I have found regarding collimating a telescope.

I found two small scraps of plastic tube that exactly fit my focus draw tube. I super glued and taped the two sections together to form a single tube. I cut the tube to the proper length, as described on Nils' website, and drilled a 1mm diameter peep hole in one end (below left photo). The crosshairs are formed from two pieces of white, nylon thread (below right photo).


 To accommodate the Cheshire eyepiece reflector, I cut a 45 degree notch in the tube (below left photo). The reflector is just a piece of heavy aluminum foil, cut from a disposable baking tray (below right photo).  The whole assembly is just super glued together.

                                                                                                                                                                                                     
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