Collimate your telescope easily with a laser pointer. Basic idea is you put a laser pointer in one end, it bounces off the secondary mirror and hits the center of the primary mirror. The beam then reflects off the primary mirror back up to the eyepiece. When properly collimated, the laser should bounce right back into the laser pointer hole.The eyepiece size is 1.25"Here's a video showing how to use a commercial version. http://youtu.be/N1asF3m2Mh0This is a bit of a test. I'm not sure a 3d printed version will be accurate enough to properly collimate a telescope. I think it will also depend on the accuracy of cheap laser pointers.This might print as a single piece as in the .stl below, but I think it'll need to be split into two pieces for the most accurate print job.It is meant to work with a cheap ~14mm dia. laser printer like this: http://www.amazon.com/532nm-Astronomy-Powerful-Green-Pointer/dp/B0019D12WWYou are welcome to try printing it as is if you like, and please add comments/suggestions.