[mura_gadi (Steve)]

Hello,

Will a reducing diameter tube as below help reduce stray light or will I end up bouncing more light around than I cancel?

This is for a 8"F9 newt btw.

Thanks
Steve

I am trying to focus on light dampening within the newt tube on my build. As baffles are so complicated or simply not worth doing, I needed a KISS work program.

Assuming it is easy to use "Newt for the Web"(nftw) to take a 230mm ID baffle intrusion at the focuser cage base. Record the baffle intrusion just up from the mirror face based on a smaller ID tube say 215mm. A few other baffles for each ID to plot a light path angle as well.

Make a plywood tube reducing in diameter from the 2XX mm ID at the sec. cage to the 2XX mm ID just above the mirror box as calculated from nftw.

Removing four triangles, with a little Pi for width to length of the triangles, from one end of the tube, you could set it fairly close to the suggested baffled optical path.

Also remove one layer of plywood in horizontal strips from tube. That would give me a hard 90 degree edge occasionally to block rather than bounce any remaining light. I was just going to have the groove wider than the depth and spaced less than the width of the groove.

All of this could be done while the board is laid out flat prior to painting, flocking etc then rolled into a tube. It seems fairly KISS friendly...

But with a reducing tube, will I bounce more light into the mirror than I can cancel with these ideas?