SKYLIGHTS
Astronomy news for the week starting Friday, August 10, 2001.
The next Skylights will appear Sunday, August 19. As the week
begins, the Moon is nearly in its third quarter, the phase passed
the night of Saturday, the 11th. During the remainder of the week
it will wane in the crescent phase until Saturday the 18th, when it
will pass new. Only three hours after new, the Moon passes
perigee, the coincidence causing near-maximum ocean tides. The
last glimpse of the crescent will be in twilight the morning of
Friday, the 17th.
As the crescent wanes, it will appear to the west of Saturn (still
in Taurus to the east of the Hyades) the morning of Monday the
13th, and to the east of the ringed planet the following morning.
The morning of Wednesday the 15th, the Moon will appear up and to
the right of Jupiter (the planet in western Gemini). During the
day, around 3 PM Central Time, the Moon will actually occult (pass
over) Jupiter, the event visible through a telescope. (Saturn's
occultation on the 13th is visible only in Africa and India). The
most striking pairing will occur the morning of Thursday the 16th,
when Moon will appear nearly to brush brilliant Venus, the event
well worth getting up at dawn to see. While less dramatic, the
evening still holds bright Mars, the planet still just a bit to the
east of Antares in Scorpius. Finally, distant Uranus, now in
retrograde in eastern Capricornus, passes opposition to the Sun on
Wednesday, the 15th.
The week, however, as always this time of year belongs to the famed
Perseid meteor shower, which will be at maximum the morning of
Sunday the 12th. Meteors are caused by small rocks from space that
heat and streak through the Earth's upper atmosphere. The Perseid
shower typically sends 50 to 100 meteors per hour (the show best
seen well after midnight). Unfortunately, the third quarter Moon
will light the sky this year, taking out the fainter meteors.
Nevertheless, the brighter ones will shine through. The meteors
are the stony debris from Comet Swift-Tuttle, which on its 130 year
orbit last passed by the Earth in 1992. The direction of the
meteoroid stream coupled with the direction of the Earth makes the
meteors seem to come from the constellation Perseus. The best
place to look, however, is straight up.
When observed at the same time of night, the stars slip slowly past
us by a degree each successive day as the Earth orbits the Sun. To
the south at 9 PM Daylight Time find the tail of Scorpius, to the
east the figure that makes Sagittarius. Above Sagittarius is a
bright patch of Milky Way coupled to modern constellation Scutum,
the Shield. Below Sagittarius are a few stars that make the modern
constellation Telescopium, the Telescope, whose stars appear
overhead to those near 50 degrees south latitude. To the far
north, the head of Draco, the Dragon, is high in the sky, and near-
overhead for those near latitude 50 degrees north.
