17 Oct 2001 @ 15:50, by sindy
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Our Blue Moon Calculator says that in 2001, there will be a Blue Moon in November. You may have heard or read reports which say that the Blue Moon really occurs in October, or even in December. Who is right?
Well, you could see Blue Moons in all three months, but it depends where in the world you live.
Let's start with the basic astronomical facts. The last four Full Moons in 2001 are as follows:
2 October at 13:49 GMT
1 November at 05:41 GMT
30 November at 20:49 GMT
30 December at 10:40 GMT
These dates and times have been calculated rigorously using the same methods as those used by the United States Naval Observatory and by Her Majesty's Nautical Almanac Office. They are given in Greenwich Mean Time (GMT) which is the standard time zone used by astronomers worldwide.
Notice that the second Full Moon in the list occurs just 5 hours and 41 minutes after the start of November, and the third Full Moon is just 3 hours and 11 minutes before the end of the month. In either case, changing the time zone by only a few hours will change the month in which the Full Moon falls.
Here are those four Full Moons again, but with the dates and times adjusted for several major time zones around the world. For each time zone, the two Full Moons which fall in the same calendar month are highlighted. We have ignored daylight saving time because it has no effect on the dates of the Full Moons.
City Time zone Full Moon 1 Full Moon 2 Full Moon 3 Full Moon 4
Places East of Greenwich
Sydney GMT 11 hours Oct. 3
00:49 Nov. 1
16:41 Dec. 1
07:49 Dec. 30
21:40
Tokyo GMT 9 hours Oct. 2
22:49 Nov. 1
14:41 Dec. 1
05:49 Dec. 30
19:40
Islamabad
(Pakistan) GMT 5 hours Oct. 2
18:49 Nov. 1
10:41 Dec. 1
01:49 Dec. 30
15:40
Moscow GMT 3 hours Oct. 2
16:49 Nov. 1
08:41 Nov. 30
23:49 Dec. 30
13:40
The Greenwich Meridian
London GMT Oct. 2
13:49 Nov. 1
05:41 Nov. 30
20:49 Dec. 30
10:40
Places West of Greenwich
New York GMT - 5 hours Oct. 2
08:49 Nov. 1
00:41 Nov. 30
15:49 Dec. 30
05:40
Chicago GMT - 6 hours Oct. 2
07:49 Oct. 31
23:41 Nov. 30
14:49 Dec. 30
04:40
Los Angeles GMT - 8 hours Oct. 2
05:49 Oct. 31
21:41 Nov. 30
12:49 Dec. 30
02:40
Hawaii GMT - 10 hours Oct. 2
03:49 Oct. 31
19:41 Nov. 30
10:49 Dec. 30
00:40
As you can see, places in time zones between New York and Moscow will see two Full Moons in November.
However, if you are in Chicago's time zone, or further west, then November has only one Full Moon. Instead, there are two Full Moons in October.
Likewise, if you are further east than Moscow's time zone, both October and November have only one Full Moon each, and it is December which has two.
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