Tuesday, April 03, 2007

full moon April 2

Here in Washington our cherry blossoms are full out just as the moon is also full. Flickr has photos that I've reproduced below. This first full moon following the vernal equinox -- the paschal moon -- has great significance in the Christian calendar. A 17th-century mathematician, John Pell, is one of many who have explained how the date of Easter is calculated. If you're interested you can read his explanation below the photos. There's a modern account -- one of many -- at the Naval Observatory web site.

{Sources: 1: pulppulse2, 2: philliefan_9, 3 & 4: glass window.}

A pamphlet on calculating the date of Easter:

{Click to enlarge. Source: 15. Pell, John, 1611-1685. Easter not mis-timed a letter written out of the countrey to a friend in London concerning Easter-Day. London : Printed for Timothy Garthwait et al, 1664.}

Pell was a reticent man and it's characteristic of him that this little pamphlet is an anonymous work. Apparently it was popularly believed that Easter in 1664 should have fallen on April 3 rather than April 10. Though it's written in answer to a query, it may have been commissioned by an acquaintance, bishop Gilbert Sheldon. See Noel Malcolm and Jacqueline Stedall, John Pell (1611-1685) and his correspondence with Sir Charles Cavendish (Oxford UP, 2005) 186.)

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