From: Frank Reed
Date: 2020 Sep 8, 15:28 -0700
It's a good teaching instrument, but it's important to understand that these Yoder sextants were built (from what I have been able to determine) for classroom use. That is, they are training instruments, never intended to see sunlight! Students could learn the basic optical principles of a sextant and understand the fundamentals of sextant adjustment, but these sextants were not quite fit for navigation. I wouldn't be shocked if one of these could be coaxed into measuring altitudes to +/- a quarter of a degree on a good day, but a well-adjusted plastic sextant can do five times better any day. I'm not saying they're junk, or that one shouldn't buy one. They would be well-suited to piloting uses, if you're into that! For celestial sights, the results would probably be disappointing.
With all that disclaimer out of the way, I should add that I'm sorely tempted to buy a Yoder sextant at that price, strictly for classroom demos. So thank you, Simon, for pointing it out!