When I was in graduate school, back around the time of Inquisition, I took a physical oceanography course. One of our lab activities was to pass a sextant around the class while we were standing on top of the sand dunes at Moss Landing Marine Lab and shoot the sun. We got shots more or less every 2-3 minutes for about 45 minutes bracketing LAN. Then as a class we graphed them...time on the X axis and angle on the Y axis. "Graph" meant with an ancient invention called "graph paper". Upshot...you drew a smooth curve through the points on the graph and adjusted for the height of the dunes and son of a gun but if we didn't get our latitude to within about 4 miles.
I did some reading and figured out how to get longitude from that measurement as well. "All" you need is a reasonably accurate digital clock set to Greenwich time. I was so intrigue'd by the whole process that I bought a secondhand Tamaya sextant in 1996 and went out to Half Moon Bay a few times to practice before I went to Hawaii that year. I took 3-4 noon sights on the way over that year, and discovered that taking sights off the beach is easy compared to taking sights off a small boat!
I subsequently sold the Tamaya, but now have the "better" model plastic Davis sextant in my garage.
Years ago when I was working at the Marine Science Institute, I used cheapo plastic Davis sextants to teach kids how to fix their position on the Bay with horizontal sextant angles and a three-arm protractor. It's pretty remarkable how accurate that is.
Last edited by AlanH; 05-11-2017 at 01:41 PM.
1968 Selmer Series 9 B-flat and A clarinets
1962 Buesher "Aristocrat" tenor saxophone
Piper One Design 24, Hull #35; "Alpha"