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Photo of the Week.Twilight.

Astronomy news for the week starting Friday, June 27, 2014.

Having passed its new phase the morning of Friday, June 27, the Moon climbs as a waxing crescent out of western evening dusk. Technically you could see the slim crescent by the evening of the Saturday the 28th, but it would be a difficult catch, as would be its passage five degrees south of Jupiter. From the evening of Monday the 30th through Thursday, July 3, the growing crescent will glide beneath Leo, as the celestial Lion gradually gives way to western twilight. The evening of Tuesday the 1st, the Moon will be south of Regulus. We don't see first quarter until next week, the morning of Saturday the 5th. The Moon passes apogee, where it is farthest from the Earth, on Monday the 30th, as May turns to June.

Jupiter is pretty much gone, hidden by evening twilight. But we get to see Mars and Saturn in one viewing, both planets in the southwest as evening falls. Bright reddish Mars, which is now in rapid direct, or easterly, motion relative to the background stars, will be to the northwest of Spica in Virgo, and closing in on it. To the left (east) find Saturn still in Libra between Alpha and Beta Librae, the two planets proceeding in stately fashion toward the western horizon. Mars sets about 1 AM Daylight Time, Saturn an hour and a half later. The naked-eye sky is then planetless until Venus rises around 3:30 AM shortly after the beginning of dawn. On the morning of Wednesday the 2nd, Venus passes four degrees north of Aldebaran, the star practically invisible.

The major story of the week is of Earth, which passes aphelion, the point in its orbit farthest from the Sun, 94.5 million miles (152 million kilometers), 1.67 percent farther than average, on Thursday the 3rd. That aphelion passage occurs during the high heat of northern summer immediately tells that the seasons have little to do with distance from the Sun. Instead they are overwhelmingly produced by the 23.4 degree tilt of the Earth's axis against the orbital perpendicular. Solar distance has a minor effect that is effectively lost in the distribution of moderating oceans. And as if to celebrate US Independence Day, Pluto (almost lost within the Milky Way in Sagittarius) goes through opposition with the Sun the morning of Friday the 4th.

Look upward to the north in mid-evening to see the bowl of the Little Dipper high above the North Star, Polaris. Local artificial lighting will hide most of the Dipper, but the two front bowl stars, also called "the Guardians of the Pole," might shine through. To the east rise the stars of summer along with the glory of the Milky way, which is richest toward the south in Scorpius (which really does look like a scorpion) and Sagittarius (with its obvious "Little Milk Dipper"), the latter hosting the center of the Galaxy and its supermassive black hole of four million solar masses.

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