Sky & Telescope's News Bulletin - Jul 30
From: Stuart Goldman (stuartgoldman_at_aol.com)
Date: 07/31/04
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Date: 31 Jul 2004 03:35:25 GMT
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* * * SKY & TELESCOPE's WEEKLY NEWS BULLETIN - July 30, 2004 * * *
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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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ASTRONOMY DAY 2004 EFFORTS LAUDED
Since 1989 SKY & TELESCOPE has honored amateur organizations whose events and
displays best exemplify Astronomy Day's goal of "Bringing Astronomy to the
People." On July 24th, at the AstroCon 2004 awards ceremony in California, the
Georgia Southern Planetarium and the Statesboro Astronomy Club were honored for
this year's winning effort....
> http://SkyandTelescope.com/news/article_1312_1.asp
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LENSING STAR WEIGHED
Astronomers have a new set of scales for measuring the masses of stars - by
watching the way a star's gravity bends the light of a distant background star.
According to Einstein's general theory of relativity, every massive object
warps the space around it, deflecting the path of anything -- including light
-- that passes nearby. Thus, a massive star's gravity can act like a magnifying
glass, making the stars it passes in front of appear to brighten, a phenomenon
called microlensing.
In 1993 the Massive Compact Halo Object (MACHO) project, which surveyed
millions of stars for signs of microlensing, recorded a very unusual event in
the direction of the Large Magellanic Cloud (LMC), a satellite galaxy of the
Milky Way. A star in the LMC brightened and faded over a period of 75 days, but
unlike in other microlensing events, the star's color seemed to change too.
That's because the lensing star, which is usually too faint to see in these
passages, was uncharacteristically bright and contributed its own light. In
fact the star was bright enough for the Hubble Space Telescope to image it
several times after it had drifted away from the line of sight to the
background star....
> http://SkyandTelescope.com/news/article_1311_1.asp
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DOES CLARISSA HAVE A MOON?
In spite of recent indications that asteroid 302 Clarissa has a moon circling
around it, evidence now suggests that the object may be alone in the cosmos
after all. On June 24th, four observers in the northeastern United States
watched as the asteroid occulted the star SAO 118999. Astronomers predicted
that the magnitude 9.6 star would drop in brightness for about 1.8 seconds as
Clarissa eclipsed it. But surprisingly, three observers, David Dunham, Frank
Suits, and Michael Richmond, timed a much longer extinction -- almost 3 seconds
-- indicating the asteroid was larger, and therefore covered the star longer
than predicted.
Preliminary calculations by David Dunham, president of the International
Occultation Timing Association, suggested that Clarissa is 64 kilometers long
by 35 km wide, nearly twice its expected diameter. Yet the fourth observation,
taken by Phil Dombrowski, was much shorter than predicted, only a
0.25-second-long disappearance. Dunham initially reported this short
observation to be a possible companion of Clarissa, perhaps one 5 or 6 km
across. Dombrowski observed the event visually and recorded it on video from
outside the predicted path where he should have seen any dimming, suggesting
that he observed a mini moon swinging past the star.
Dombrowski's moonlet observation hasn't held up to further scrutiny,
however....
> http://SkyandTelescope.com/news/article_1307_1.asp
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IS THE JULY 31ST FULL MOON REALLY "BLUE"?
On Saturday evening, July 31st, a full Moon will rise for the second time this
month (the first time was on July 2nd). Many people call the second full Moon
in a calendar month a "blue Moon" and use the expression "once in a blue Moon"
to mean something that occurs only rarely. While the latter meaning can be
traced back centuries, the former definition is much newer -- and it's
wrong....
> http://SkyandTelescope.com/news/article_1310_1.asp
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HIGHLIGHTS OF THIS WEEK'S SKY
* Full Moon on Saturday July 31.
* Neptune is at opposition (opposite the Sun in our sky) on the night of
Thursday, August 5.
* Last-quarter Moon on Saturday, August 7.
For details, see This Week's Sky at a Glance and Planet Roundup:
> http://SkyandTelescope.com/observing/ataglance/
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charts highlighting the best celestial sights for the year, SkyWatch has become
an annual "must buy" for amateur astronomers of all skill levels. If you're in
the market for a new telescope, our expanded Telescope Buyer's Guide lets you
compare the features of 230 scopes priced up to $5,000.
> http://SkyandTelescope.com/SkyWatch
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Copyright 2004 Sky Publishing Corp. S&T's Weekly News Bulletin is provided as a
free service to the astronomical community by the editors of SKY & TELESCOPE
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http://SkyandTelescope.com/news/.
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which calls attention to noteworthy celestial events, go to this address:
> http://SkyandTelescope.com/shopatsky/emailsubscribe.asp
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*-----------------------------------------------------*
| Stuart Goldman sgoldman@SkyandTelescope.com |
* Associate Editor StuartGoldman@aol.com *
| Sky & Telescope |
* 49 Bay State Rd. Sky & Telescope: The Essential *
| Cambridge, MA 02138 Magazine of Astronomy |
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