Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. Waves of high clouds accent a
turquoise sky.
Astronomy news for the week starting Friday, July
30, 2004.
Skylights now resumes its normal weekly schedule. Thanks for your
patience.
We begin the week with the Moon just shy of its full
phase, which it reaches on Saturday, July 31, around noon,
causing the full Moon
to rise a bit after sunset in North America. Since July already
saw a full Moon on Friday, July 2nd, this one is by folk tradition
called a "blue moon," which derives from a sort of orphanage status
in which the full Moon name-of-the-month has already been taken (in
North America, the month of July holding the "thunder moon" or "hay
moon").
A few hours after full, the Moon passes five degrees to the south
of Neptune. Then as our companion wanes in its gibbous
phase toward third quarter (that phase reached next Saturday,
August 7), it crosses south of Uranus on Monday, August 2. Since the Moon
encounters Neptune near the lunar full phase, the planet must also
be close to opposition to the Sun, which it achieves on Thursday,
August 5, the planet still ensconced within Capricornus (Uranus in Aquarius south of the "Water Jar"). While Uranus is --
at bright sixth magnitude -- visible to the naked eye (though
hardly under full Moon conditions), Neptune requires large
binoculars or at least a small telescope to see.
As August begins, Jupiter" sets at the
end of "
astronomical twilight" (when the Sun reaches 18 degrees below
the horizon and the sky becomes fully dark), and is increasingly
difficult to see. The twilit evening of Sunday, August 1, finds it
below Denebola in Leo and above and to the left of
little
Mercury, which is quickly disappearing as it heads toward
inferior conjunction with the Sun.
Planetary glory now lies in the morning sky with Venus, which is rising almost as early as
possible for this apparition, just before 3 AM Daylight Time,
tucked into eastern Taurus and
shining at nearly minus fifth magnitude. Complementing Jupiter, Saturn now
rises at the beginning of astronomical twilight, the ringed planet
slowly drifting eastward within east-central Gemini.
'Tis the season of Scorpius, the
great constellation of the Zodiac that looks very much like the
Scorpion it represents. For those in mid-northern latitudes,
Scorpius seems to skim the southern horizon. The constellation is
so far south that those living north of 47 degrees north latitude
even begin to miss the lower end of the Scorpion's tail. Down and
to the right of Scorpius is the bright figure of Lupus, the Wolf, which requires more
southerly latitudes to admire, while directly east is the striking
figure of Sagittarius, the Archer,
which holds the brightest portion of the Milky Way. Far to the north of Sagittarius, and almost
overhead in the early evening for northerners, find Vega in Lyra, the Harp, the star that anchors the northwestern
apex of the Summer Triangle,
the others of which are Deneb in Cygnus and Altair in Aquila.
