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. Mercury, seen in evening twilight, can be remarkably bright - and then it is gone. Courtesy of Robert H. Olley, with thanks.

Astronomy news for the two weeks starting Friday, May 20, 2016.

The next skylights will appear June 3.

We begin with the Moon late in its waxing gibbous phase just a day shy of full, which takes place the evening of Saturday, May 21, with the Moon rising to the left of Mars and above Antares and Saturn, the quartet making a ragged box. By the following evening the Moon will be to the left of Saturn, with Antares off to the right. The Moon then drifts through its waning gibbous phase, which ends at third quarter on Sunday the 29th, the near-perfect phase taking place near sunrise in North America with the Moon high to the south. We then get to watch the waning crescent, which closes out our fortnight, new Moon taking place on Saturday, June 4. The morning of Friday the 3rd the super-thin crescent will rise in morning twilight just beneath Mercury, providing a fine way to find the little planet. Binoculars would be a good idea. Having passed apogee on Wednesday the 18th, the Moon spends the entire fortnight moving slightly, about 11 percent, closer to Earth, passing perigee (nearest to Earth) on Friday the 3rd.

Already west of the celestial meridian as the sky darkens, Jupiter dominates the evening, setting roughly an hour past local midnight. Already up in the southeast in evening twilight, Mars and Saturn make a fine pair, Mars in fast retrograde (to the west against the stars), Saturn retrograding much more slowly to the east of Mars and to the northeast of Antares, the trio making a very pretty sight, especially when the Moon gets out of the way. Mars is in opposition to the Sun on Sunday the 22nd, Saturn's opposition following on Friday the 3rd. At those special times, the planets will rise at sundown, cross the meridian to the south at local midnight (approximately 1 AM Daylight), and set at sunrise. Mars, now very bright and rivalling Jupiter, undergoes closest approach to the Earth for this orbital round on Monday the 30th, when it will be half an Astronomical Unit (Earth-Sun distance), 46 million miles, or 75 million kilometers, from us. That closest approach is 8 days after opposition is the result of the eccentricity of the Martian orbit. Not to be entirely left out, Venus goes through superior conjunction with the Sun on June 6.

To the southwest of Jupiter lies Alphard, the luminary of Hydra, the Water Serpent, the name from Arabic meaning "the solitary one," which has nothing to do with a snake. To the northeast of the giant planet is Denebola, Leo the Lion's number two, the name referring to the beast's tail, both stars about the brightness of Polaris, the North Star, which is at the end of the handle of the Little Dipper.
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