|I printed the image from the Bahtinov Focusing Mask Generator on cardstock|
|...and cut out the white spaces...|
|...which took me about 20 minutes.|
|Then I cut out the disk itself.|
|I wrapped paper around the end of my telescope and taped it for size, then attached the focusing mask with tape.|
|I figured it doesn't really matter if the white or black side faces out. Looks kinda badass.|
Even this paper one works in principle - it "produces three angled diffraction spikes at the focal plane of the instrument" (Wikipedia). The problem is that my focuser sticks and jumps, and I only have a course focus. Knowing where focus is doesn't help if you can't accurately make adjustments - I just shoot past it in both directions but can't fine tune it. Oh well, not a bad little project!