Skylights featured on Astronomy Picture of the Day

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Skylights featured nine times on Earth Science Picture of the Day: 1 2 3 4 5 6 7 8 9 -- Full List Restored!


Photo of the Week. Floating along.

Astronomy news for the two weeks starting Friday, July 17, 2015.

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 21st.

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.

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