A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2015 Apr 19, 12:19 -0700
It seems that Gary the Astronomer's floating picture frame works guys. There are a few tricky things that need doing to get the 1' accuracy.
1. The glass of the frame has to be silicone glued into the frame for water tightness.
2. All the bubbles need to be removed from under the frame when setting into the tray of water (not easy).
3. Water drops on the frame and glass must be removed with a sponge before making any observations.
4. Two observations need to be made with the tray turned 180° on the second observation. The average of the two intercepts will be the accurate result within 1'.
I was not pleased with the asymmetrical image of the Sun as reflected of the frame glass although the intercepts worked out when the centers of the Sun were lined up. A better image was had by placing a small mirror at the center of the frame.
For best accuracy I still prefer the wind shielded water dish. The floating frame with mirror on top is the better option if observing dim stars such as Polaris.