NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Moon Meridian Passage
From: Lu Abel
Date: 2013 Sep 22, 17:06 -0700
From: Lu Abel
Date: 2013 Sep 22, 17:06 -0700
In the extreme lower right hand corner of each page of the (US) Nautical Almanac, there's an entry about the Moon. The table lists "meridian passage" for the moon, with two subtables titled "upper" and "lower" No explanation of them is given in the prefactory material to the NA. It appears as if there's a 12h 25m difference between the two numbers, so I'm guessing that "upper" is the time the moon is over my meridian and "lower" is the time that it's at my anti-meridian (ie, 180 degrees opposite my latitude). Is this correct? Where does the terminology originate, especially "lower meridian passage?" I tried a fairly extensive Google search and got lots of info on the moon's passage over my meridian (which, as mentioned, I suspect is the "upper" in the table) but nothing on this "lower meridian." Thanks Lu
