NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2024 Jun 4, 22:47 -0700
My "hour" of errands ran to about four hours earlier today leaving me no time to post those promised photos until now.
The first pair are profile photos of the spherical sundial taken on Sunday, 2 June 2024, during our lunch break from my "Lunars" workshop. These images are similar to the cover photos from the "Sundials" book and should provide anyone interested with better source material for direct measurement of angles.
The second pair of photos are nearly-simultaneous comparisons of the "sundial time" or "Local Apparent Time" or "true time" reading taken from two sundials at the Treworgy Planetarium at Mystic Seaport Museum. On the left in each pair is the scale with gnomon shadow on the armillary sphere with the little problem we've been discussing. On the right in each pair we see an anchor sundial on the south side of the planetarium building. The shaft or "shank" of the anchor is the gnomon for this sundial. Each of the anchor sundial images was captured about 75-90 seconds after each of the sphere sundial images. You can see that they don't agree. The filenames indicate the dates and times for the initial (sphere) image in each comparison.
Frank Reed
