De astronomische kalender

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Op dinsdag 19 oktober 2004 11:06 schreef pfaf het volgende:
Mooie OP -CRASH-
En van mijn kant een schaamteloze t.v.p.

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Solar Cycle Update
by Dr Tony Phillip
for NASA Science News
Huntsville AL (SPX) Oct 19, 2004

Solar physicist David Hathaway has been checking the sun every day since 1998, and every day for six years there have been sunspots. Sunspots are planet-sized "islands" on the surface of the sun. They are dark, cool, powerfully magnetized, and fleeting: a typical sunspot lasts only a few days or weeks before it breaks up. As soon as one disappears, however, another emerges to take its place.

Even during the lowest ebb of solar activity, you can usually find one or two spots on the sun. But when Hathaway looked on Jan. 28, 2004, there were none. The sun was utterly blank.

It happened again last week, twice, on Oct. 11th and 12th. There were no sunspots.

"This is a sign," says Hathaway, "that the solar minimum is coming, and it's coming sooner than we expected."

Solar minimum and solar maximum - "Solar Min" and "Solar Max" for short -are two extremes of the sun's 11-year activity cycle. At maximum, the sun is peppered with spots, solar flares erupt, and the sun hurls billion-ton clouds of electrified gas toward Earth.
[...]
"Contrary to popular belief," says Hathaway, "the solar cycle is not precisely 11 years long." Its length, measured from minimum to minimum, varies: "The shortest cycles are 9 years, and the longest ones are about 14 years."
[...]
"We examined data from the last 8 solar cycles and discovered that Solar Min follows the first spotless day after Solar Max by 34 months," explains Hathaway.

The most recent solar maximum was in late 2000. The first spotless day after that was Jan 28, 2004. So, using Hathaway and Wilson's simple rule, solar minimum should arrive in late 2006. That's about a year earlier than previously thought.

The next solar maximum might come early, too, says Hathaway. "Solar activity intensifies rapidly after solar minimum. In recent cycles, Solar Max has followed Solar Min by just 4 years." Do the math: 2006 + 4 years = 2010.

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Op donderdag 21 oktober 2004 14:56 schreef whosvegas het volgende:
In het bovenstaande overzichtje van astronomische software, is nog een programma vergeten: Stars. Stars is een nederlands planetarium programma (met de sterrenbeelden in de gewone nederlandse benamingen). Homepage van Stars:
http://home.planet.nl/~romme102

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Op zaterdag 23 oktober 2004 13:52 schreef gigatech het volgende:
De top is toch echt Starrynight 5 op dit moment is een perfect programma voor de amateur astronoom met een database die "volledig is"

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Op zaterdag 23 oktober 2004 13:52 schreef gigatech het volgende:
De top is toch echt Starrynight 5 op dit moment is een perfect programma voor de amateur astronoom met een database die "volledig is"

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Op zaterdag 23 oktober 2004 14:03 schreef Quarks het volgende:

[..]

De pro plus versie
Daar is de prijs dan ook wel naar.
Voor de serieuze amateur is het wel fantastisch.

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Op zaterdag 23 oktober 2004 13:52 schreef gigatech het volgende:
De top is toch echt Starrynight 5 op dit moment is een perfect programma voor de amateur astronoom met een database die "volledig is"

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Op zaterdag 26 november 2005 00:57 schreef -CRASH- het volgende:
GOOD LUCK, JAPAN:
The Japanese Space Agency's Hayabusa probe is trying again today
(26-11) to land on asteroid Itokawa.
Its mission: to collect samples of the asteroid for return to Earth in 2007.
Stay tuned for updates.
[afbeelding]

[afbeelding]
Above: The shadow of space-probe Hayabusa on asteroid Itokawa.
What makes the ground around the shadow glow?
That's the opposition effect.
At the sub-solar point, the shadows of, e.g., rocks and pebbles and
grains of dust are hidden directly beneath the rocks and pebbles and dust.
The absence of shadows causes the brightening.

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Op zaterdag 26 november 2005 15:04 schreef star_gazer het volgende:
Het is gelukt met die Japanse sonde

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Op maandag 12 december 2005 20:02 schreef Boswachtertje het volgende:
Prachtig topic Crash! Duidelijk een tvp! Ideaal, alleen nu nog combineren met Het Astronomie Topic van Quarks

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All (known) bodies in our Solar System larger than 320 kilometer in diameter
http://kokogiak.com/solarsystembodies_metric.jpg

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Op donderdag 25 oktober 2007 22:34 schreef -CRASH- het volgende:
Strange Comet:
Astronomers around the world agree, Comet 17P/Holmes is one of
the strangest things ever to explode in the night sky. It's a comet,
yet it looks like a planet with a golden core and a green atmosphere

[ link | afbeelding ]

Chris Shur of Payson, Arizona, took this picture last night using his
12.5-inch telescope and a Canon XTi digital camera.
"The comet was yellow and green, very bright in the viewfinder," he says

Yesterday, Comet Holmes shocked sky watchers with a spectacular eruption,
brightening almost a million-fold from 17th to 2.5th magnitude in a matter of hours.
The comet is now visible to the naked eye--even from light polluted cities--high in the
northern sky after sunset: finder chart.

The golden hue of Holmes' core is probably the color of sunlight scattered by comet dust,
while the green fringe likely signifies an atmosphere rich in diatomic carbon and cyanogen
(substances found in many green comets). There are reports that the fuzzball is expanding
and taking on a lopsided shape--the first signs of a tail? Amateur astronomers are encouraged
to monitor developments. After sunset, point your backyard telescope at the extra "star
" in the thigh of Perseus.