Sky & Telescope's News Bulletin - Feb 18

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* * * SKY & TELESCOPE's WEEKLY NEWS BULLETIN - February 18, 2005 * * *

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Welcome to S&T's Weekly News Bulletin. Images, the full text of stories
abridged here, and other enhancements are available on our Web site,
SkyandTelescope.com, at the URLs provided below. (If the links don't
work, just manually type the URLs into your Web browser.) Clear skies!

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THE BRIGHTEST BLAST

On December 27, 2004, more than a dozen spacecraft recorded the
brightest event from outside the solar system ever observed in the
history of astronomy. The spacecraft, which included Earth-orbiting
satellites as well as interplanetary probes such as Cassini, Mars
Odyssey, and Ulysses, picked up a powerful burst of gamma rays and
X-rays from one of the most exotic beasts in the galactic zoo: a
magnetar. These bizarre objects are neutron stars possessing magnetic
fields a million billion times more powerful than Earth's field, or
some 1,000 times greater that those of normal neutron stars.

The "superflare," from a magnetar named SGR 1806-20, irradiated Earth
with more total energy than a powerful solar flare. Yet this object is
an estimated 50,000 light-years away in Sagittarius, on the far side of
the Milky Way galaxy behind dense interstellar clouds. "This is
mind-boggling when you think about how far away it is," says Kevin C.
Hurley (University of California, Berkeley), one of the lead
investigators....

http://SkyandTelescope.com/news/article_1464_1.asp

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PICTURE IMPERFECT: NASA'S SPITZER SPACE TELESCOPE

NASA officials acknowledge that two of the space agency's premier
orbiting telescopes share a common problem: flawed optics. One is the
15-year-old, multibillion-dollar Hubble Space Telescope, which made
"spherical aberration" a household term before being rehabilitated in a
spectacular rescue mission by Space Shuttle astronauts. The other,
overlooked until this week, is the $720 million infrared Spitzer Space
Telescope.

The problem has been hiding in plain sight since NASA released the
first Spitzer image on September 3, 2003, a week after launch. At that
point the 85-centimeter (33-inch) reflector -- then called the Space
Infrared Telescope Facility -- hadn't yet been focused, so its bloated,
triangular star images didn't raise any eyebrows....

http://SkyandTelescope.com/news/article_1463_1.asp

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ASTRO NEWS BRIEFS

Astronomers Celebrate Pluto's 75th Birthday

In 1929 Lowell Observatory's director, Vesto M. Slipher, tasked a young
Clyde William Tombaugh to search for "what else is out there beyond
Neptune." Tombaugh was supposed to find Percival Lowell's predicted
Planet X. One year later, on February 18, 1930, he spotted Pluto.

The status of the ninth planet has come under heavy debate in recent
years. Astronomers now realize that Tombaugh's find is the largest
known member of an entire class of objects known as the Kuiper Belt.
These ice-rock bodies, circling the Sun beyond the orbit of Neptune,
have helped astronomers better understand the formation of our solar
system and other extrasolar planetary systems. But Ceres, the largest
asteroid in the asteroid belt, isn't classified as a planet, so why
should the largest Kuiper Belt object have such an honorable
distinction? Pluto's status remains a hot topic despite the
International Astronomical Union's ruling in favor of its current
classification as "planet." In December 1994, Tombaugh wrote a letter
to the editor published in SKY & TELESCOPE where he explained his
opinion on the matter:

"Pluto started out as the ninth planet, a supported fulfillment of
Percival Lowell's prediction of Planet X. Let's simply retain Pluto as
the ninth major planet. After all, there is no Planet X. For 14 years,
I combed two-thirds of the entire sky down to 17th magnitude, and no
more planets showed up. I did the job thoroughly and correctly... Pluto
was your last chance for a major planet."

Winds on Titan

Due to a programming error between the European Space Agency's Huygens
probe and NASA's Cassini orbiter, some of the former's observations
were thought to be lost forever. One of the missing measurements was
the Doppler Wind Experiment, designed to profile Titan's atmospheric
wind speeds as Huygens floated toward the moon's surface.

Fortunately, a worldwide armada of radio telescopes also listened for
Huygens's signal. From those observations scientists have learned that
the wind speed on Saturn's largest moon is weak at the surface but
increases slowly to about 60 km. It peaks at a speed of 430 kilometers
(270 miles) per hour in a zone located about 120 km high.

http://SkyandTelescope.com/news/article_1462_1.asp

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HIGHLIGHTS OF THIS WEEK'S SKY

* Full Moon on Wednesday, February 23rd.
* Jupiter (magnitude -2.3, in Virgo) rises in the east around 9 or 9:30
p.m. and is well up in the southeast by midnight -- the brightest
"star" in the sky. By dawn Jupiter shifts over to the southwest.
* Saturn (magnitude -0.2, in Gemini) shines brightly very high in the
southeast to south during evening, excellently placed for telescopic
viewing.

For more details, see This Week's Sky at a Glance and Planet Roundup:

http://SkyandTelescope.com/observing/ataglance

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Copyright 2005 Sky Publishing Corp. S&T's Weekly News Bulletin is
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Stuart Goldman
Associate Editor http://SkyandTelescope.com
Sky & Telescope http://NightSkyMag.com
49 Bay State Rd.
Cambridge, MA 02138