A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2017 Aug 18, 13:07 -0700
Ed Popko, you wondered:
"why leave out usual data? Does anyone know why? Sure, you might not be able to observe it, but its position is still predicted."
Yeah, I would say that it's just a part of the publishing tradition of the modern Nautical Almanac. If there were a consistent argument that the Moon could not be used for navigation, then its data would be dropped every month for some hours around New Moon. And on the other hand, as you say, the data are known and available so why not include the numbers and remind readers about the eclipse in some other way? It's just tradition. Solar eclipses in general have no navigational value in the modern world, and yet the almanacs dutifully publish the charts. Why? Tradition.
Needless to say (but I'll say it anyway!) if anyone wants to fill in those numbers for August 21, 2017, you can do so easily with the web app at the UNSO web site here: http://aa.usno.navy.mil/data/docs/celnavtable.php.
By the way, is anyone, maybe outside the US, having any lingering difficulty accessing this UNSO app? I can set up an alternate entry point if that's an issue.