NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2015 Sep 11, 11:05 -0700
Norm, looking at your graphic of your observations and reading off the errors from the diamonds, I find a standard deviation in your data of about 1.7 minutes of arc. Whether this is good or bad or somewhere in the middle depends a lot on the details. What sort of sextant were you using? What magnification on the scope? You mentioned that you could see no detectable 'disks' for the two planets, and since both were around a minute of arc across, that suggests a rather low magnification (or mediocre focus). The human eye with "20/20 vision" has a resolution of one minute of arc which puts the planets' disks at the limit of detection with unaided vision. With any magnification, it's clear that they are not "point" sources of light, though of course no details are visible with the normal range of magnifications on sextant scopes.
Do you have the raw data for your observations: the angle as measured (corrected for index error, preferred) and the time when the angles were measured (within five minutes would be good enough)?
Frank Reed
