[time-nuts] Calculating time of lunar eclipse

[Bill Beam]

According to my copy of Guide9 (Pluto project) full moon occurred at 21 Jan 05:16:04 UTC.

On Mon, 21 Jan 2019 07:07:31 +0000, Mark Sims wrote:

>While on the subject of the accuracy/reliability of various algorithms and web pages showing various astronomical data, we had a full moon / 
total lunar eclipse in the northern hemisphere.  And not just any full moon, but a Super Blood Werewolf Zombie Apocalypse full moon (or 
some such drivel spouted by all the TV stations).

>Anyway, I wanted to know when the eclipse was at it's maximum.  Most web sites gave a time here as 23:12,  some differed by several 
minutes.  None gave the time to the second.  That just won't do for a moon worshiping time-nut, will it?  So, I tricked up a version of Lady 
Heather to do a screen dump when the difference of the  sun and moon azimuth and elevation were at a (180 degree) minimum.  Looks like it 
happened at 23:12:04

>Heather's sun position code (based on Grena's algorithm 5) is VERY accurate (and quite simple).  The moon position code is pretty good... 
a better version would require several thousand lines of code evaluating a zillion polynomials with hundreds of terms.

>Anyway,, attached is a copy of the screen dump.  Note the difference in the sun/moon az/el values and also the calculated moon phase.

>Does anybody know of a reliable source of the true time of the lunar eclipse down to the second (or better)?


Bill Beam
NL7F