A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2015 Apr 19, 18:35 -0700
No, the 2.3° error in longitude you found would not be acceptable under any circumstances. You mentioned that you observed this "lunar" (stretching the meaning a bit) during the solar eclipse. But what exactly did you measure? What angular distance? And could you post your raw observational data? It's nearly impossible to "debug" observations like this without the original data. I do have one guess on one possible source for your problem. If you measured the angle from the Moon's limb superimposed on the Sun to the limb of the Sun on the same side, which is the only thing that I can think of that you would have been able to measure, that doesn't "fit" in the usual classification of lunars. It's neither a "near" nor a "far" limb lunar. There are ways to adjust for this, so it's still a usable observation if that's the case, but the usual tools and algorithms are not set up for this special eclipse case.
PS: You mention that you used a spreadsheet to clear or work your lunar observation, and then you referenced my web site. There are web tools to clear lunars on my web site, but no spreadsheets. Are you perhaps using Peter Hakel's spreadsheets? He's here, too, and can help with questions on those.