Completely Baffled!

Improved  baffling of the six inch folded refractor

In my design there is a bulkhead near the focuser. See Constructing a Folded Refractor. This is mostly for structural support of the tube. It increases the rigidity. But the baffling incorporated at that point is fairly ineffective. The geometry makes it nearly impossible to block stray light from the objective (like an off-axis street light) from entering the eyepiece. However, I was able to do a very effective job of baffling by making a stop that fits on the inside of the focuser tube. That is the way Unitron did it and it seems to work just fine.

Focuser Baffling

The focuser at the top of the picture is from a Unitron 131C, 75mm folded refractor. At the bottom is the draw tube from my scope. Notice that I have put a blackened light stop at the end of the draw tube. The size of the hole in my version is only 7/8 inch. This is just barely enough for full illumination at the center of my eyepiece. I am using the scope for planetary and lunar observation so this works well for me. I can easily enlarge the opening if necessary but the light fall-off at the edge of the field is not even noticeable. And stray light from my irritating street light is not a problem.