TheSkySearchers

printed this simple spherometer, didn't have ball end grub screws but it does have 3 printed contact points that some what work until i get some adjustment screws , i purchased joe's old mirror he had in storage from an old project he started years ago, i gave it a little test run, it read f5.47 @ 1380mm fl , the mirror is very close to where i want it to be. atm i'm also working on a 3d printed bath interferometer

https://www.thingiverse.com/thing:3957102

And here's part of the bath interferometer, need to order some prisms and a laser

Nice stuff Rob. I couldn't quite remember the final f ratio but I think I said I thought it was somewhere around f5.6, not bad memory after 40 years!

If you can manage with the current f5.5, you can go straight to polishing. This will save you a lot of time, having to glue glass facets to the tool then grind them in to match the surface then remove the facets afterwards prior to polishing.

How important is that extra 1/2 stop?

Will be following this project with interest.

Good luck

Joe