archive: SETI [ASTRO] Sky & Telescope's News Bulletin - Dec 4, FWD from

SETI [ASTRO] Sky & Telescope's News Bulletin - Dec 4, FWD from

Larry Klaes ( )
Mon, 07 Dec 1998 12:18:58 -0500

>X-Authentication-Warning: majordom set sender
to owner-astro using -f
>Date: Fri, 4 Dec 1998 18:30:06 -0600
>From: (Paul M. Rybski)
>Subject: [ASTRO] Sky & Telescope's News Bulletin - Dec 4, FWD from Stuart
> <>
>Reply-To: (Paul M. Rybski)
>DECEMBER 4, 1998
>While the second attempt to launch the Space Shuttle Endeavour -- and the
>second piece of the International Space Station -- was successful early
>this morning, it remains to be seen if the second try to launch NASA's
>Submillimeter Wave Astronomy Satellite (SWAS) does likewise. Originally
>scheduled for launch from Vandenberg Air Force Base, California, on the
>evening of December 2nd, the send off was aborted because of problems with
>tracking data. SWAS will study the composition of interstellar matter at a
>wavelength that cannot be examined from Earth's surface. It will be boosted
>into orbit by a Pegasus-XL winged rocket dropped from an L-1011 jet
>aircraft. The spacecraft was checked over and another launch attempt will
>be made this afternoon Pacific time.
>A short-lived hydrocarbon has been identified above Neptune's cloud decks,
>potentially solving a riddle that has had planetary scientists scratching
>their heads for years. The methyl radical (CH3) is highly reactive and thus
>rarely found by itself in nature. But European astronomers using the
>Infrared Space Observatory (ISO) believe they have recorded emissions from
>the molecule in Neptune's upper atmosphere. Methyl's presence there could
>explain the planet's surprisingly high concentration of ethane (C2H6).
>Ethane forms only in the presence of sunlight, which breaks down methane
>(CH4) molecules into methyl and hydrogen, whereupon the methyl radicals
>combine to form ethane. So how can the abundance of ethane on Neptune be
>similar to that on Jupiter, when the former is some 5-1/2 times farther
>from the Sun and therefore illuminated much less strongly? The answer,
>according to Bruno Bezard (Paris Observatory), Paul Romani (NASA/Goddard
>Space Flight Center), and their colleagues, is that turbulent storms on the
>distant planet loft methane high above the cloud tops, exposing much more
>of it to the feeble sunlight than would be the case if it remained deeper
>in the atmosphere. Such a suggestion would have been laughed at before
>Voyager 2 and the Hubble Space Telescope showed that Neptune is a dynamic
>world where violent storm systems rage with surprising frequency. But
>methyl's telltale infrared emissions were picked up by ISO exactly where
>suspected -- at high altitudes above the planet -- suggesting that the
>chemical reactions needed to produce ethane are indeed going on there.
>Presumably the ethane, once formed, settles into the planet's lower
>atmosphere, where its puzzlingly high concentration was detected earlier.
>Astronomers at the European Southern Observatory (ESO) continue to put the
>new Very Large Telescope (VLT) through its paces. So far only one of the
>VLT's four 8.2-meter reflectors is operational; the others will see first
>light over the course of the next two years (see Massimo Tarenghi's article
>in the November 1998 *Sky & Telescope*). Last week ESO observers presented
>a selection of new images and spectra from Unit Telescope 1 (UT1), as the
>first of the four glass giants is called, including data gathered by a new
>infrared instrument named ISAAC -- the Infrared Spectrometer And Array
>Camera. As with earlier results, these new ones demonstrate that UT1 is
>performing spectacularly, meeting -- and in some cases exceeding -- all
>expectations. Observations with UT1 have now gone well beyond simple
>testing and calibration. Numerous teams of astronomers have used the giant
>eye to tackle important scientific questions, including the nature of
>high-redshift galaxies, the geometry of gravitational lensing, and the
>origin of icy bodies in the outer solar system.
>Comet C/1998 U5 (LINEAR) remains the brightest comet in the evening sky, at
>about magnitude 8.5, just beating out Comet 21P/Giacobini-Zinner. This week
>it passes through the southeastern corner of Cygnus. Visit
> for more details
>about the comet and a finder chart. Here are positions for the coming week
>at 0:00 Universal Time in 2000.0 coordinates:
> R.A. Dec.
>December 05 21h 45m +32.2 deg.
>December 07 21h 39m +30.1 deg.
>December 09 21h 34m +28.3 deg.
>Meanwhile, Comet Giacobini-Zinner will be leaving Capricornus and entering
>Aquarius this coming week. It should be 9th magnitude and situated,
>depending on your latitude, between 15 and 40 degrees above the southern to
>western horizon after the end of evening twilight. For a finder chart, see
>page 107 of the November *Sky & Telescope,* or visit
> Here are
>positions for Comet Giacobini-Zinner for the coming week:
> R.A. Dec.
>December 5 21h 44m -19.8 deg.
>December 7 21h 56m -20.5 deg.
>December 9 22h 07m -21.1 deg.
> Some daily events in the changing sky, from the editors of SKY &
> * Earliest nightfall of the year (if you live near latitude 40 degrees
> * Seen in a medium-sized telescope, Jupiter's Great Red Spot should cross
>Jupiter's central meridian (the imaginary line down the center of Jupiter's
>disk from pole to pole) around 11:18 p.m. Eastern Standard Time. Lately the
>spot has been very pale tan with a darker reddish mark in its south side.
>For a list of all predicted Red Spot transit times, see
> * The eclipsing variable star Algol should be in one of its periodic
>dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours
>centered on 6:55 p.m. EST. Algol takes several additional hours to fade and
>brighten. For a list of all its predicted minima see
> * Some doorstep astronomy: Look for the constellation Orion above the
>east-southeast horizon by about 8 p.m. By around 9, the brilliant star
>Sirius is rising beneath Orion.
> * Jupiter's Red Spot should transit around 7:09 p.m. EST.
> * Mira, the prototype long-period variable star in Cetus, should still be
>near maximum brightness; its peak was predicted for December 1st. Mira
>usually brightens to about magnitude 3.4 at the peak of its 11-month cycle,
>but this year's maximum has been rather faint. See the February 1997 Sky &
>Telescope, page 66.
> * Earliest sunset of the year (at latitude 40 degrees north).
> * Jupiter's Red Spot transits around 8:48 p.m. EST.
> * The Moon appears close to Regulus late tonight. The Moon occults
>(covers) Regulus as seen from Florida around 11 p.m. EST; watch with a
> * Jupiter's moon Io reappears from eclipse by Jupiter's shadow a little
>east of the planet around 8:06 p.m. EST. Then at 8:47 p.m. EST, the tiny
>black shadow of Europa begins crossing Jupiter from the east just as Europa
>itself emerges into view on Jupiter's western limb. For a full listing of
>Jupiter's satellite events, see the December Sky & Telescope, page 120.
> * Jupiter's Red Spot transits around 10:27 p.m. EST.
> * Last-quarter Moon (exact at 12:53 p.m. EST).
> * Tonight 12th-magnitude asteroid 245 Vera should occult a 10.2-magnitude
>star on the Taurus-Gemini border for observers along a narrow track from
>the Northeast to the West Coast. The occultation, which could last for up
>to 8 seconds, should take place around 4:35 Universal Time December 11th in
>Nova Scotia and 4:41 UT in Oregon or California. See the December Sky &
>Telescope, page 123, or
>DEC. 11 -- FRIDAY
> * Jupiter is at quadrature, appearing 90 east of the Sun in our sky.
> * Look southeast before dawn Saturday morning to see Mars, the Moon, and
>3rd-magnitude Gamma Virginis forming a small triangle about 2 degrees long
>(as seen from the Americas). Gamma Virginis is a close double star in a
> * Keep an eye out for early Geminid meteors! The Geminid shower should
>peak tomorrow night. See the December Sky & Telescope, page 117.
> * Jupiter's Red Spot transits around 7:58 p.m. EST.
> ============================
> ============================
>MERCURY is emerging just above the east-southeast horizon before sunrise.
>It gets easier to see later in the week.
>VENUS may be visible in bright twilight shortly after sunset, just above
>the southwest horizon.
>MARS, magnitude +1.3, shines high in the southeast before and during dawn.
>Spica is the star well to its lower left. Brighter Arcturus shines farther
>to Mars's left.
>JUPITER, magnitude -2.4, is the big, brilliant "star" high in the south
>during early evening. You can't miss it! Jupiter moves lower toward the
>southwest in late evening and sets around midnight.
>SATURN, magnitude +0.1, is the yellowish "star" far to Jupiter's left just
>after dark, and to Jupiter's upper left later in the evening. The two
>planets appear 38 degrees apart (about 4 fist-widths at arm's length), on
>opposite ends of Pisces. Saturn's rings are currently tilted 14 degrees to
>our line of sight.
>URANUS and NEPTUNE are disappearing into the sunset.
>PLUTO is hidden behind the glare of the Sun.
>(All descriptions that relate to the horizon or zenith 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
>minus 5 hours.)
>More details, sky maps, and news of other celestial events appear each
>month in SKY & TELESCOPE, the essential magazine of astronomy. See our
>enormous Web site at Clear skies!
>SKY & TELESCOPE, P.O. Box 9111, Belmont, MA 02478 * 617-864-7360 (voice)
>Copyright 1998 Sky Publishing Corporation. S&T's Weekly News Bulletin and
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