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Friday, November 19, 2010

Once in a blue moon

You've really got to be a geek to find this fascinating:
On the almanac page for August 1937, the calendrical meaning for the term "blue moon" was given.

That explanation said that the moon "... usually comes full twelve times in a year, three times for each season."

Occasionally, however, there will come a year when there are 13 full moons during a year, not the usual 12. The almanac explanation continued:

"This was considered a very unfortunate circumstance, especially by the monks who had charge of the calendar of thirteen months for that year, and it upset the regular arrangement of church festivals. For this reason thirteen came to be considered an unlucky number."

And with that extra full moon, it also meant that one of the four seasons would contain four full moons instead of the usual three.

"There are seven Blue Moons in a Lunar Cycle of nineteen years," continued the almanac, ending on the comment that, "In olden times the almanac makers had much difficulty calculating the occurrence of the Blue Moon and this uncertainty gave rise to the expression 'Once in a Blue Moon.'"


Not sure i buy the reasoning that 13 became unlucky because it upset the "regular arrangement of church festivals," but there may be some evidence that the extra 13th moon is at the root of the number 13's significance. But let's leave that aside for the moment. The article goes on to precisely note the introduction into the culture of the now common belief that the blue moon is, in fact, the second full moon of a calendar month. It cites specifically a radio broadcast of a program called Star Date, from January 31, 1980, which in turn cited another Sky & Telescope article from 1946 misinterpreting the previous article referenced above.

I remember that Star Date episode - i was volunteering at the time at a college radio station that aired the program twice daily. And i pocketed that little tidbit of knowledge. And somehow i just assumed that it was something that calendar makers had been doing since the days of the Julian calendar or so, that is, denoting the occasional second full moon of a month by showing it in blue.

But that is apparently not the case. And so, in a season of 4 full moons, which happens 7 times every 19 years, the third full moon is the one which should receive the designation "blue." And since the September full moon occurred after the equinox, and the December full moon will occur slightly before the winter solstice, that makes the November full moon the third of this autumn.

Color it blue.

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Friday, September 17, 2010

By Jupiter!

Two moons! OMG! Not for the next 200 years!

OK, not really. But Jupiter is making it's closest pass to us in almost 50 years. So go look at it over the next week or two.

The best part?
There's more to see in the heavens right now than just Jupiter. The giant planet is lined up almost perfectly with Uranus at the moment.

Uranus is five times farther away and almost 3,000 times dimmer than Jupiter, so it's invisible to the unaided eye. But binoculars or a telescope — as well as access to a detailed chart — will show Uranus less than 1 degree from Jupiter now through Sept. 24, Sky and Telescope said. (A fist held at arm's length covers about 10 degrees of the sky.)

So, when someone asks if that's Uranus? You can say, why yes, yes it is.

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Sunday, November 01, 2009

Our house

It's a very fine house.

From Space.com

Dr. Axel Mellinger of Central Michigan University gets the credit for assembling this montage of the Milky Way.

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Friday, October 16, 2009

And the word is . . .

Analemma!

On the radio last night, Kevin and i got sidetracked a bit into a discussion of the sun, started by my observation that last night's show was the first of the season to start after it was completely dark outside.

I knew that the path the sun travels in the sky throughout the year is roughly figure 8 shaped (actually more like the infinity sign, with one end larger than the other, but couldn't recall the word for this.

And that word is analemma. You can read all about it here.

And look at a pretty amazing analemma image at the NASA site. What's remarkable about this one is that one of the exposures of the sun was taken during a total eclipse.


Maybe i read about analemmas here.

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Friday, November 14, 2008

On the other hand

Maybe things are going better out on Fomalhaut B?

Photo credit: Paul Kalas/UC Berkeley; STScI

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Wednesday, June 11, 2008

They should have called them "Goofies"

It rolls off the tongue better.
Pluto is finally getting its day in the sun, after being stripped of planetary status by astronomers two years ago.

From now on all similar distant bodies in the solar system will be called "plutoids." That's the decision by the International Astronomical Union, which met last week in Oslo, Norway, and announced the decision Wednesday.

The same group raised a cosmic fuss when it demoted the once-ninth planet to "dwarf" status in 2006. The new policy allows Pluto to be the standard for a whole new category of dwarf planets.

Pluto is one of only two plutoids, the other being Eris. Both are objects that circle the sun and are too small to be considered planets, but big enough to have a level of gravity that keeps them in a near spherical shape. Plutoids also must be farther from the sun than Neptune.

When Pluto was demoted, the astronomical union always planned on naming the new category of objects after the former planet, but had to find the right name, said IAU president Catherine Cesarsky, a French astrophysicist. Their first choice, pluton, was already used by geologists.

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Monday, April 14, 2008

Video worth watching

This is worth 90 seconds of your time. Trust me. (And no cute kitties, either)

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