Tag Archives: solar filter

How to Make a Solar Filter

By Captain James R. Watson

The sun is magnificent to view through a telescope—but only with a filter. Building a solar filter for a telescope is pretty straight forward.

To build one for my telescope, I sawed two 1″-wide rings from 1/4″-thick plywood. The inside diameter of the rings matches the outside diameter of my telescope’s optical tube (10 3/4″). I bonded the two larger rings together with an identically-sized ring of foam between them. The laminated ring slides over the tube. Continue reading