Astronomy news for the two weeks starting Friday, July 17,
The next skylights will appear July 31, 2015.
With the Moon just past new (on Wednesday, July 15), we first see
the waxing crescent climb the western
evening sky heading toward first
quarter the night of Thursday the 23rd roughly about the time
of moonset in North America. It then enters the waxing gibbous phase, reaching full just after our fortnight ends, on
Friday the 31st, again about the time of moonset. For reasons that
apparently involve the Maine Farmer's Almanac, Sky and
Telescope, and various interpretive errors, this second full
Moon in a month is called a
blue moon, the event happening once a year or so. While
it highlights the length of the lunar phase cycle, the blue moon
has no physical meaning. The Moon goes through apogee, where it is farthest from Earth, on Tuesday
The early evening of Saturday the 18th will feature a spectacular
lineup, with the thin crescent Moon tucked just under Venus, Jupiter
to the right, and the star Regulus hovering above them all.
Even the next night will be great, with the Moon now up and to the
left of the remaining trio. Look next the night of Saturday the
25th to see the Moon just to the right of Saturn, the Moon passing north of the planet after
midnight. By the night of Saturday the 26th, the Moon will have
flipped to the other side of Saturn.
Jupiter and Venus stay close to each other during the second half
of the month. The two came into conjunction on July 1, and will
do so again on Friday the 31st with brighter Venus now 6 degrees
to the south. By then they will be setting in bright twilight and
difficult to see. So enjoy them early. Afterward look for Saturn
northwest of Antares, the planet
transiting the meridian shortly after
sunset and setting not long after local midnight. Mercury, out of sight, goes
through superior conjunction with (on the other side of) the Sun
on Thursday the 23rd, while
Uranus resumes normal easterly motion against the stars on
Sunday the 26th.
The Delta Aquarid meteor shower, which is active in late
July and early August, peaks around the 28th and 29th. Its 20
meteor per hour rate however will be ruined by the bright Moon.
As the sky darkens, look for bright Arcturus west of the meridian,
with the rest of kite-shaped Bootes to north it. Following to the east is the
graceful curve of stars that forms Corona Borealis, the Northern Crown, then Hercules, bright Vega (which marks Lyra, the Harp or Lyre), and finally
Cygnus, the Swan, which holds Deneb and flies along the bright Milky Way.