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SKY & TELESCOPE'S NEWS BULLETIN - JANUARY 4, 2001
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For images and Web links for these items, visit http://www.skypub.com
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ASTRONOMERS MEET IN WASHINGTON
This coming week many of the world's research astronomers will turn
their attention to Washington, D.C., for 199th meeting of the American
Astronomical Society. This twice-yearly convention draws hundreds of
professional astronomers, educators, and astronomy hobbyists to hear
front-line research reports on topics ranging from the solar system to
the edge of the observable universe. Check SKY & TELESCOPE's Web site
(http://www.SkyandTelescope.com/) for daily reports from on-the-scene
editors Joshua Roth and David Tytell.
YOHKOH LOSES CONTROL
On December 14, 2001, the Japanese solar observatory Yohkoh began
spinning out of control. Since then, all scientific operations have
stopped, and it remains unclear when the craft will be operational
again.
The problem began during last month's annular eclipse of the Sun.
Yohkoh uses a Sun-centering system to determine its position at any
given time. During the eclipse, the craft lost contact with the Sun,
put itself into a "safe mode," and slowly began to drift off track and
rotate. Normally this wouldn't have been a problem -- during its
decade in orbit, Yohkoh has seen its share of eclipses. However, this
event occurred during a rare period of the craft's orbit (known as an
invisible orbit) when the craft was out of communication with Earth.
Thus controllers on the ground couldn't detect (or compensate for) the
craft's sudden roll.
Problems only got worse from there. Because of its slow roll, Yohkoh's
solar panels no longer received direct sunlight. By the time ground
controllers at the Kagoshima Space Center regained contact with the
observatory, its batteries were very low and the craft had lost
attitude control.
To fix the problem, scientists first established contact and turned
off all the craft's science instruments in order to conserve power.
Currently the craft is rotating slowly, about one rotation per minute.
According to Loren Acton (Montana State University), head scientist of
Yohkoh's solar X-ray telescope, in the spacecraft's current state, its
solar panels only receive sunlight in spurts. "During flashes of
illumination, electricity is produced," says Acton. Thus the first
step toward recovery is for scientists to wait until the craft can
charge up.
It's currently unclear when, and even if, scientists will regain
control of the craft. But astronomers are hopeful. "It will take
clever work to stop the roll and reacquire the Sun," says Acton.
COMET LINEAR FAR SOUTH
Comet LINEAR (C/2000 WM1) shines at about 6th magnitude, but is only
visible for Southern Hemisphere observers. This coming week, the comet
moves through Indus, as it nears its closest approach to the Sun --
called perihelion -- on January 22nd. As twilight fades, the comet
will be about 20 to 25 deg. above the southwestern horizon. Here are
positions for the coming week in 2000.0 coordinates:
R.A. Dec.
Jan 5 21h 49m -53.7 deg.
Jan 7 21 38 -54.2
Jan 9 21 27 -54.5
Jan 11 21 16 -54.6
THIS WEEK'S "SKY AT A GLANCE"
Some daily events in the changing sky, by the editors of Sky &
Telescope.
JAN. 6 -- SUNDAY
* A grand array of bright winter constellations and planets fills
the southeastern sky during evening this month. Brightest is Jupiter
in the east. High above it is Capella. To Jupiter's right is the
constellation Orion. High above Orion is Saturn (with slightly fainter
Aldebaran just under it). Equally far below Orion is brilliant white
Sirius.
To identify stars and constellations all around your sky, use the
evening star map and instructions at
http://www.skypub.com/sights/northern/0201skyn.html (if you're in the
mid-latitudes of the Northern Hemisphere. Southern Hemisphere
skywatchers: use the map at
http://www.skypub.com/sights/southern/0201skys.html .)
* Jupiter's Great Red Spot should cross Jupiter's central meridian
(the imaginary line down the center of the planet's disk from pole to
pole) around 12:01 a.m. Eastern Standard Time tonight. The "red" spot
is very pale orange-tan. It should be visible for at least 50 minutes
before and after in a good 4- or 6-inch telescope if the atmospheric
seeing is sharp and steady. Our complete list of Red Spot transit
times, at http://www.skypub.com/sights/moonplanets/redspot.html , is
good worldwide.
JAN. 7 -- MONDAY
* Jupiter's moon Europa emerges out of eclipse by Jupiter's shadow
around 9:50 p.m. Eastern Standard Time. A small telescope will show it
gradually swelling into view just off the planet's eastern limb.
* Jupiter's Red Spot transits around 7:52 p.m. EST.
JAN. 8 -- TUESDAY
* Look southeast as dawn begins to brighten on Wednesday morning.
There you'll spot the waning crescent Moon. Below it is the summer
star Antares, just starting to make its annual winter emergence from
the glow of sunrise.
* The 8.6-magnitude asteroid 9 Metis is passing 15 arcminutes north
of Pollux late tonight. There's no star there that bright to confuse
it with.
JAN. 9 -- WEDNESDAY
* Jupiter's Red Spot transits around 9:30 p.m. EST.
JAN. 10 -- THURSDAY
* Some doorstep astronomy: Have you seen the Orion Nebula, M42, in
binoculars? During the evening, find Orion striding up the
southeastern sky to the right of brilliant Jupiter. In Orion's middle
is the three-star row of Orion's Belt, almost vertical. To the Belt's
lower right is a fainter, diagonal row of stars similarly long,
Orion's Sword. Closely surrounding one of the middle stars of the
Sword is the small, dim, gray-green glow of the nebula.
JAN. 11 -- FRIDAY
* Mercury reaches greatest eastern elongation, 19 degrees east of
the Sun.
* Saturn's largest moon, Titan, is located three or four
ring-lengths west of Saturn tonight through Sunday night. A small
telescope will show it.
* Jupiter's Red Spot transits around 11:08 p.m. EST.
JAN. 12 -- SATURDAY
* Jupiter's moon Io crosses the planet's face from 7:37 to 9:52 p.m.
EST, closely followed by its tiny (but much more visible) black shadow
from 7:55 to 10:10 p.m. EST.
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THIS WEEK'S PLANET ROUNDUP
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MERCURY is having a good apparition at dusk. Look for it low in the
southwest about 45 to 60 minutes after sunset. It's the only bright
point of light there.
VENUS remains hidden in the glare of the Sun.
MARS (magnitude +0.9, at the Aquarius-Pisces border) is the orange
"star" in the south-southwest during twilight. It sinks lower in the
southwest later in the evening and sets around 10 p.m.
JUPITER (magnitude -2.7, in Gemini) is just past opposition. It's the
brightest point of light in the sky -- blazing white in the east
during evening, high in the south in the middle of the night, and low
in the west before dawn.
SATURN (magnitude -0.2, in Taurus) shines high in the east far to
Jupiter's upper right during early evening. Later at night it's in the
south directly to Jupiter's right. The star Aldebaran sparkles just 4
degrees (two or three fingers's-widths at arm's length) from Saturn --
below it in early evening, to its lower left later. Compare their
colors. Saturn is pale yellow; Aldebaran is more orange.
URANUS and NEPTUNE are lost in the sunset.
PLUTO (magnitude 14, in Ophiuchus) is barely up in the east-southeast
before dawn.
(All descriptions that relate to the horizon or zenith -- including
the words up, down, right, and left -- are written for the world's
midnorthern latitudes. Descriptions that also depend on longitude are
for North America. Eastern Standard Time, EST, equals Universal Time
[GMT] minus 5 hours.)
More celestial events, sky maps, observing projects, and news of the
world's astronomy research appear each month in SKY & TELESCOPE, the
essential magazine of astronomy. See our enormous Web site and
astronomy bookstore at http://SkyandTelescope.com/ . Clear skies!
SKY & TELESCOPE, 49 Bay State Rd., Cambridge, MA 02138 *
617-864-7360
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and Sky at a Glance stargazing calendar are provided as a service to
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