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Re: Sun, distances and self-confidence
From: Frank Reed CT
Date: 2005 Jun 11, 03:11 EDT
From: Frank Reed CT
Date: 2005 Jun 11, 03:11 EDT
Fred you wrote: "Does anybody have any suggestions for measuring shade error?" Do an index correction using the Full Moon bringing the Moon's direct limb into contact with the limb in the reflected image (you could also use the bright, shimmering horizon directly under the Sun --over water, that is). Then swing in each shade individually, one shade at a time, without touching the micrometer. If there's significant shade error, you will see it right away as a gap or overlap that was not there previously. Adjust the micrometer until that difference disappears and record the change. Shade errors, of course, add linearly so if you know that shades A, B, and C have separate errors of +0.5, +0.7, and -1.0 minutes of arc then using all three together, e.g. for a Sun sight, would yield a net shade error of +0.2 minutes of arc. -FER 42.0N 87.7W, or 41.4N 72.1W. www.HistoricalAtlas.com/lunars