[time-nuts] Calculating time of lunar eclipse

[Chris Burford]

Mr. Eclipse, hosted by Fred Espenak,  is your go-to page for this. The data for both solar and lunar eclipse events seems to be accurate based on my experience of past events.

http://www.eclipsewise.com/lunar/LEprime/2001-2100/LE2019Jan21Tprime.html


---- Mark Sims <holrum at hotmail.com> 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)?