Photo of the Week. Twilight first quarter Moon (20
hours past the exact phase) with delicate clouds.
Astronomy news for the two weeks starting Friday, August 14,
2015.
The next skylights will appear August 28, 2015.
The symmetry between our fortnight and the lunar phases nicely
continues, with new Moon taking place on Friday, August 14, and full Moon on Saturday, August 29, during
the day in North America, so the Moon will rise a bit past the
phase that evening. After the new phase, the Moon will wax as a
crescent, culminating in first quarter on Saturday the 22nd, with the Moon
already climbing the daytime sky. You might get your first look
at the ultra-thin crescent in western twilight the evening of
Saturday the 15th. Following first quarter, the Moon grows in the
gibbous phase until it finally passes
full. The evening of Friday the 21st the Moon will lie to the
west of Saturn, while
by the following night it will have flipped to the other side.
Our companion passes apogee, where
it is farthest from Earth, on Monday the 17th.
Throughout most of the year, Jupiter and Venus dominated the
nightly skies. Now the two do a disappearing act as Venus goes
through inferior conjunction with the Sun
(more or less between it and us) on Saturday the 15th, while
Jupiter will pass solar conjunction on Wednesday the 26th. The
evening now belongs to Saturn. Still northwest of Antares in Scorpius but moving easterly against the background
stars, in the middle of our period the ringed planet sets around
11:30 PM Daylight time. In the morning, Mars begins to make an
appearance, rising about the beginning of dawn. Far away
and still faint, it's hard to spot. Mars will pass nine degrees
north of Venus, which begins to make its own notable
appearance, as our period closes.
As the days of August cool into those of September, the Big Dipper begins to fall into the
northwest, while the "W" of Cassiopeia rises in the northeast. South of the
Dipper's curved handle lie the
two stars that make up the modern constellation of Canes Venatici, the Hunting Dogs,
while further down is the lacy sprawl of Coma Berenices, one of the closest star clusters to Earth.
On the other side of the sky, Perseus, which follows Cassiopeia in its rising, is
home to the much more distant, but equally famed, Double Cluster. In early
evening, Scorpius and Sagittarius (the latter to the east
of the Scorpion) are nicely paired low in the south. Below
Sagittarius, notable by its "Little
Milk Dipper," lies the ragged semicircle that makes Corona Australis, the Southern Crown,
whose counterpart, Corona
Borealis, the Northern Crown, fits nicely between Hercules and Bootes to the northeast of orange Arcturus, the brightest star of
the northern celestial hemisphere.
