Photo of the Week. The Seven Sisters peek around the trees.
Astronomy news for the week starting Friday, June 26, 2009.
The week begins with the Moon in its waxing crescent phase just over halfway
to first quarter, that phase reached
the morning of Monday June 29, with the Moon out of sight. By the
time it rises that afternoon, it will already have begun its waxing gibbous phase, which will occupy
the week's remaining days. The evening of Friday the 26th finds
the Moon to the left of Regulus
in Leo. The following evening,
it's Saturn's
turn, with the Moon passing seven degrees south of the ringed
planet, after which the Moon heads towards Spica in Virgo.
Though the Moon and planets all ply the Zodiac, all have their own orbital
tilts relative to the plane of the ecliptic (that of Earth's
orbit), the Moon's tilt 5.5 degrees, Saturn's 2.4 degrees. As the
Moon passes Saturn, the Moon's tilt is taking it near its maximum
angle south of the ecliptic, while Saturn is now near its most
northerly position, hence the above seven or so degree minimum
separation between the two for this passage.
Saturn, well into the western sky at the end of twilight, is about
it for the early evening. The next planet in line is Jupiter, which
rises about 11 PM Daylight Time on the border between Capricornus and Aquarius about an hour before Saturn sets, briefly
giving us both the giant planets at the same time. The morning sky
holds equal promise. Watch next for the rising of reddish Mars, which
comes up just after 2:30 AM Daylight in far eastern Aries near the border with Taurus. Then less than half an
hour later, near 3 AM comes the big show with brilliant Venus, the sky
still dark and an hour from the onset of dawn, during which Jupiter
transits the meridian to the south.
In lesser news, Uranus, in
southern Pisces just south of the
Circlet (and barely visible to
the naked eye), begins
retrograde motion on Wednesday, July 1.
The Summer stars, epitomized by the Summer Triangle, are now climbing the evening sky. Look
for bright Vega in Lyra in the northeast, followed by Deneb in Cygnus, with the southern anchor of the Triangle, Altair in Aquila close to the celestial
equator. Deneb also serves as the top star of the informal
figure of the Northern Cross, which is Cygnus (the Swan) turned
upside down. At the bottom of the Cross lies Albireo, Beta Cygni, a fine double star. Coming off
of it in a stream to the southeast is a set of small constellations, first modern dim
Vulpecula (the Fox), then ancient
Sagitta (the Arrow), Delphinus (the Dolphin, which looks
like a hand with a finger pointing south), and Equuleus (the Little Horse).
