A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2015 Dec 22, 14:05 -0800
The difference of 0.9' between spotting scope zero and x7 scope zero is high ? Reading the vernier off the arc incorrectly perhaps ? Try a straight visual of the micrometer drum when off the arc as a check. Read from 30' the additional minutes with an estimate of tenths of a minute by eye on the micrometer drum (no vernier). Both Sun images should be well shaded and of equal brightness. Remember to keep the Sun focused sharp. Pressing the eye to the occular repeatedly can change focus. I pencil mark the sharp focus setting. Be sure to take fingers off the micrometer before calling the mark. Some micrometer drums move when the fingers are released.
From: Robin Stuart
Date: 2015 Dec 22, 12:14 -0800