FULL MOON and fullest moon
t20mxs1 at CORN.CSO.NIU.EDU
Tue Dec 21 18:11:20 UTC 1999
Sali Tagliamonte wrote:
> Check out the following URL for debunking of the FULLEST FULL MOON urban myth!
It hardly qualifies as an urban myth. It's more like a slight
mythinformation. Nonetheless, I concede. Sali Tagliamonte has one-upped
my PAAAC (Pedantic Accuracy At All Costs), by the merest whisker. This
year's coincidence is not quite as rare as I implied . . . but it's
The response, however, is well done. PAAAC isn't PAAAC unless it's
carried to extremes. See for yourself, below.
-- mike salovesh <salovesh at niu.edu> PEACE !!!
>>From SKY AND TELESCOPE magazine --
> Wednesday, December 15: Brightest Moon in 133 Years? >
>Suddenly a lot of people are asking this question:Will the full Moon of
>December 22, 1999, be the brightest full Moon in 133 years? They're
>asking, apparently, because of an article in the Old Farmer's Almanac
>that is being widely circulated by e-mail.
>According to Roger W. Sinnott, associate editor of Sky & Telescope
>magazine, the answer is unequivocal: No!
>It is true that there is a most unusual coincidence of events this >year. As S&T contributing editor Fred Schaaf points out in the December >1999 issue of Sky & Telescope, "The Moon reaches its very closest point >all year on the morning of December 22nd. That's only a few hours after >the December solstice and a few hours before full Moon. Ocean tides >will be exceptionally high and low that day."
>But to have these three events -- lunar perigee, solstice, and full >Moon -- occur on nearly the same day is not especially rare. The >situation was rather similar in December 1991 and December 1980, as the >following dates and Universal Times show:
>Event Dec. 1999 Dec. 1990 Dec. 1980
>Full Moon 22, 18h 21, 20h 21, 18h
>Perigee 22, 11h 22, 9h 19, 5h
Solstice 22, 8h 22, 9h 21, 17h
>What is really rare is that in 1999 the three events take place in such
>quick succession.On only two other occasions in modern history have the
>full Moon, lunar perigee, and December solstice coincided within a >24-hour interval, coming just 23 hours apart in 1991 (as indicated in >the preceding table) and 20 hours apart back in 1866. The 10-hour >spread on December 22, 1999, is unmatched at any time in the last >century and a half.
>So is it really true, as numerous faxes and e-mails to Sky & Telescope
>have claimed, that the Moon will be brighter this December 22nd than at
>any time in the last 133 years? We have researched the actual perigee
>distances of the Moon throughout the years 1800-2100, and here are some
>perigees of "record closeness" that also occurred at the time of full >Moon:
> Date Distance (km)
>1866 Dec. 21 357,289
>1893 Dec. 23 356,396
>1912 Jan. 4 356,375
>1930 Jan. 15 356,397
>1999 Dec. 22 356,654
>2052 Dec. 6 356,421
>It turns out, then, that the Moon comes closer to Earth in the years >1893, 1912, 1930, and 2052 than it does in either 1866 or 1999. The >difference in brightness will be exceedingly slight. But if you want to >get technical about it, the full Moon must have been a little brighter >in 1893, 1912, and 1930 was the real winner, because it happened just >one day after the Earth was closest to the Sun that year. However, >according to a calculation by Belgian astronomer Jean Meeus, the full >Moon on January 4, 1912, was only 0.24 magnitude (about 25 percent) >brighter than an "average" full Moon.
>In any case, these are issues only for the astronomical record books. >This month's full Moon won't look dramatically brighter than normal. >Most people won't notice a thing, despite the e-mail chain letter that >implies we'll see something amazing.
>Our data are from the U.S. Naval Observatory's ICE computer program, >Jean Meeus's Astronomical Algorithms, page 332, and the August 1981
>issue of Sky & Telescope, page 110.
Mike, one last time: The whole point is that the distinction can't
possibly make much of a difference to an ordinary observer. We won't
have any other moon in the sky for a direct comparison. Tecnically
speaking, tonight's full moon will only be the third brightest in this
century. But it certainly will be the fullest full moon of my entire
lifetime, since I just missed the really bright one of 1930 and I hardly
expect to be around for the big in 2052.
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