Huanyu Precise Manual Goniometer Stage 65x65mm Optical Positioning Sliding Table ±10° Tilt Platform Indexing Table Angle Adjustment Dovetail Platform

Very precise

Fairly good copy of some goniometer, ultimately it does move around a ~118mm radius (?) Scale is very bad - see picture comparing to a good Melles Griot goniometer - Very coarse, big gap from one side to the other (hard to get precisely to an angle), but the worst DEFECT is the vernier, done by someone that has no idea how it should work. In a Vernier scale you typically have a second scale, where in this case 12 divisions of 60 minutes (5 minutes each) would align with 11 divisions of the other scale, so each time you move 5 minutes (1/12 of a degree) a different trace would match. Instead, they made 12 match 12, so every degree all of them match. useless as a vernier, and even inaccurate at that, they don't truly match 12:12 but 12:11.9 or so.