A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2016 Mar 18, 11:18 -0700
Bob, sounds like your presentation went well. You mentioned that 'One person asked about Slocum's $5 clock, so I touched on the idea of the lunar.'
OK. I'll bite. What did you say on this? How did you connect a lunar with Slocum's little clock? I would say that there's no connection, but there's a lot of confusion on this topic.
"I decided that rather than using PowerPoint as a way of helping people visualize a globe, I would use a GLOBE as a way of helping people visualize a globe. I cut out paper circles, then made a slit in each so that I could (more or less) make them lie down properly on the surface of the globe, to try and get across the idea of circles of position."
Bravo! I'm a firm believer in real globes for navigation workshops. If you haven't yet, you should buy yourself one from the mid-20th century. They turn up frequently on ebay and they normally have analemmas on them, which you can also bring into a navigation discussion. My latest trick is to bring globes for everyone! I've found toy globes that I can get for a dollar each, and about three-quarters of a lot are good enough for crude navigation --enough to get a fix within about 3° when provided with the GHA and Dec of the bodies and the observed (corrected) altitudes. Alas, they don't have analemmas printed on them, but that's asking too much for a buck. :)