How can I make my own collimating tool to use with my Newtonian reflector?

There are several ways to do-it-yourself when it comes to collimating tools. The easiest way is to drill a 1/16” to 1/8” hole in the center of your eyepiece drawtube dust cap, and use it as a simple collimating eyepiece. If you prefer not to try it yourself, there are other ways you can make a simple collimation tool. Your best bet is a plastic 35 mm film can. They are very nearly 1.25" diameter. Most one-hour-type photo processors discard many of these containers in the course of their business. Consequently, they may be free for the asking from these shops.

Two easy models:

1. Remove the cap. Obtain a 1/16" to 1/8" drill, and drill a hole in the very center of the bottom of the can. Clean the edges of the hole with a razor knife, so it is smooth and round. Trim the raised rim off the top. Insert bottom up. You may need to use vinyl tape to shim the film's plastic cylinder, so it fits snugly and doesn't slip readily in or out.

2. Remove the cap. Use a 1/16" to 1/8" drill, and drill a hole in the very center of the cap. Clean the edges of the hole with a razor knife, so it is smooth and round.
Cut the bottom off the main body of the film can. Reattach the cap to the body of the film can. Insert top up. You may need to use vinyl tape to shim the film's plastic cylinder, so it fits snugly and doesn't slip readily in or out.

Updated 10/18/13