for Sky & Telescope magazines's sublime Wigglegraph of the motions of the Galilean Moons of Jupiter for September 2010. You'll be amazed at how much information is displayed so clearly, in so friendly a format for the human eye and brain.
Makes a feller or a gal proud to be a carbon-based Sentient.
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Thursday 23 September 2010
(@ 03:09 UTC / Zulu / GMT more or less)
(@ 03:09 UTC / Zulu / GMT more or less)
is the Equinox. Wherever you are on the surface of Earth, the length of Day equals the length of Night. If you're in the Northern Hemisphere, Happy Autumnal Equinox; if Southern, Happy Vernal Equinox.
But now for the Big News.
I suspect my sky will be clear tonight, and I've already dragged my new (non-computerized) Celestron refractor telescope out on the porch, to see THIS!!!
Now if Jupiter is this close and this big and this bright, so are its 4 biggest Moons, so this will be your best chance to see them through an amateur telescope.
OR phone your nearest university or college with a whomp-ass observatory and telescope, or your nearest optical observatory -- the Alps, btw, are lousy with great optical telescopes -- and ask if they're having Public Viewings of Jupiter.
If they're NOT letting the public see the Wonders of the Night Sky through their Big Fancy Telescope, Leave A Comment or Write A Big Loud Rude Website Thing telling the world that they're Hostile Assholes, and your government should cancel their funding.
I've done this courtesy of the lovely and hospitable Wilder Observatory @ Amherst College. When it opened in 1903, it was one of the biggest telescopes on Planet Earth. Now
By all means, drag children. The sooner you addict a child to the Wonders of the Night Sky, the better for everybody. Would you rather they hang out in the 7-11 Parking Lot at 2 am, getting drunk, Twitting, texting, sexting, and making each other pregnant? Where do you want to read their names, in the Science Blog, or the Police Log?
These Moons are quite famous. Before telescopes, no one knew they were there. In 1609-1610, using the 30x refractor he designed from reading a letter about the invention of a telescope in Holland, Galileo found four moons around Jupiter, thereafter called the Galilean Moons. He named them Ganymede, Callisto, Io, and Europa.
Very quickly, the world's astronomers clocked the regular movements and eclipses of Galileo's moons, now so visibly regular and predictable that, in the search for a reliable, precise "clock" to determine a ship's Longitude, the Moons of Jupiter were the prime candidate.
(That scheme never worked out; the Longitude was solved with a real clock, Harrison's wooden-geared nautical Chronometer, merrily ticking away on public display at the Old Royal Observatory in Greenwich, England, designed by Christopher Wren.)
In 1671, the Danish astronomer Ole Christensen Rømer, working at Tycho Brahe's astronomy island, Uraniborg, studied irregularities -- slownesses and quicknesses -- in the motions of the Galilean satellites. The irregularities themselves revealed regularity. The eclipses of the moons came late when Jupiter was farthest from Earth, and came early when Jupiter was nearest Earth.
Rømer concluded that the eclipses ocurred late because of the extra time required for light to travel from Jupiter to his telescope at Uraniborg; and early because light had considerably less distance to travel to reach Earth.
(Previously it was assumed light was an instantaneous phenomenon, requiring no time to travel from source to observer.)
He and the Dutch physicist Christiaan Huygens used this hypothesis to compute the first accurate Speed Of Light. In their comparatively crude solar-system geometry, they computed a value for the Speed of Light as 9300 (without units). The comparable precise modern measurement is 10100. Pretty damn good for the late 17th Century.
Above, Sky and Telescope magazine's sublime Wigglegraph of the motions of the Galilean Moons of Jupiter. Please let Planet Vleeptron know if you see Jupiter during its historic Closeness, and definitely let Vleeptron know if you nail any of these famous Moons. If you see an eclipse of a Galilean Moon, and you are Not Lying, I'll buy you a Pizza & a Beer, or a Soda Pop, if you are a child, or just like Soda Pop.
The Associated Press (USA newswire)
Sunday 19 September 2010
Jupiter closest to Earth since ’63
by Marcia Dunn, AP
CAPE CANAVERAL, FLORIDA -- You’d better look for Jupiter in the night sky this week. It won’t be this big or bright again until 2022.
Jupiter will pass within 368,000,000 miles / 592,238,592 kilometers of Earth late Monday, its closest approach since 1963. It will be visible low in the east around dusk. About midnight, it will be directly overhead. That’s because Earth will be passing between Jupiter and the sun, into the wee hours of Tuesday.
The solar system’s largest planet already appears as an incredibly bright star -- 3 times brighter than the brightest star in the sky, Sirius. The only thing brighter in the night sky now is our moon. Binoculars and telescopes will dramatically improve the view as Jupiter, along with its many moons, rises in the east as the sun sets.
“Jupiter is so bright right now, you don’t need a sky map to find it,” said Tony Phillips, a California astronomer under contract with NASA. “You just walk outside and see it. It’s so eye-catching, there it is.”
Coincidentally, Uranus also will make a close approach the same night. It will appear close to Jupiter but harder to see with the naked eye. Through a telescope, it will shine like an emerald-colored disk less than one degree from Jupiter.
Jupiter comes relatively close to Earth about every 12 years. In 1999, it passed slightly farther away. What’s rare this time is Uranus making a close appearance at the same time, Phillips said. He called it “a once-in-a-lifetime event.”
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So look for all this Neat Krap tonight and the next few nights.
Afterwards, you may die at any time of your choosing or convenience. There'll be nothing better to go on living for.