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Q & A: The Moon in 1866

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Most recent answer: 11/27/2009
What happened in 1866 that will never happen again for a long, long, long, long time?(it has something to do with the moon)
- Anonymous
Well, there were actually quite a number of interesting things that happened with the moon in 1866. Here's 2 of them that may be what youíre looking for: In 1866, there was a full moon combined with winter solstice and lunar perigree. This is the time when the moon looks the absolute brightest, and itís due to happen again on December 22, 1999. (Thanks to the for this one.)

Also, in February 1866, there was no full moon. This sounds weird because it is... normally, thereís a full moon once every month. But February is the shortest month in the year, and it just so happened that year that there were two full moons in January, two in March, and none in February. This isnít expected to happen again for another two and a half MILLION years! (Whoops- see below mw.)


(published on 10/22/2007)

Follow-Up #1: Correction for no moon in February

Greetings from Cambridge, England. I'm an ex-professional astronomer. I taught mathematics and astronomy at London University and I was also on the staff of Her Majesty's Nautical Almanac Office, where my duties included calculating the phases of the Moon. I'm afraid I'm writing to correct an error regarding "The Moon in 1866". At the end of your answer, you say: "This [a February with no Full Moon] isnít expected to happen again for another two and a half MILLION years!" I'm not sure where you got that figure from, but it's very far from correct. Between 1801 and 2100, the following years have no Full Moon in February: 1800, 1809, 1847, 1866, 1885 1915, 1934, 1961, 1999 2018, 2037, 2067, 2094 You may notice a 19-year pattern in those series of years. That's called the Metonic Cycle -- 19 calendar years are almost exactly the same as 235 lunar months, so the phases of the Moon repeat on the same calendar dates at intervals of 19 years. That's how often there is a February with no Full Moon. Best regards David Harper, Ph.D. Fellow of the Royal Astronomical Society Member, IAU Commission 4, Ephemerides
- Dr David Harper
Cambridge, England
That's an oops for us.   You are absolutely right.  The Greek astronomer Meton figured it out in the fifth century BC.  See: 
Thanks for the correction.

Nota bene:  for some interesting interactive astronomy applications see Dr. Harper's


(published on 11/27/2009)

Follow-Up #2: correction

The date and time of a full moon are generally recorded at Greenwich Mean Time as a standard, since the full moon happens at an exact moment, but time zones (and even dates) vary around the globe. Yes, in 1866 there were two full moons in January, none in February and two in March. However, it wasn't 2.5 million years before this happened again. It indeed happened as recently as 1999!
- Greg (age 46)
Middletown, NY, USA

Mike W.

(published on 07/23/2008)

Follow-up on this answer.