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Photo of the Week.A darkening sky from which emerge the stars.

Astronomy news for the week starting Friday, September 26, 2014.

The Moon starts our week as a thin waxing crescent just barely visible in western twilight the evening of Friday, September 26, and then grows steadily fatter as it climbs the sky toward first quarter, 90 degrees east of the Sun, the phase passed on Wednesday, October 1, with the Moon visible in the daylight sky. We then get to see a bit of the waxing gibbous as the week comes to an end. The evening of Saturday the 27th, the crescent will make a classical appearance just to the west of Saturn, looking like it is about to gobble the planet. And in a sense it will, as the Moon will actually occult Saturn as seen from various parts of the eastern hemisphere (but not here). In a remarkable coincidence, the Moon will also occult the asteroids Ceres and Vesta within a few hours of covering Saturn, again neither of the events visible from North America. The following night, that of Sunday the 28th, the Moon will appear to the right of Mars, while the evening of Monday the 29th it will lie atop both Mars and (farther down) Antares. On the evening of Wednesday, October 1, the growing crescent, now near first quarter, will glide north of the Little Milk Dipper of Sagittarius.

As is obvious from the lunar passage, Saturn is sinking out of sight, being lost to the brightness of twilight. It's been a good run over the past several months. Mars, though, falls only slowly behind the Earth in orbit, and is moving quickly to the east relative to the background stars. It not only stays quite visible throughout the remainder of the year, but even improves some relative to the end of twilight as winter approaches, the red planet now setting about an hour and a half after the sky gets fully dark. The big Martian event is its conjunction with the similarly-colored star Antares (the planet three degrees to the north) on Saturday the 27th. We are then planetless until Jupiter makes its striking appearance, rising around 2:30 AM Daylight Time in eastern Cancer well to the southeast of the Beehive Cluster. We can forget about Venus until it moves into evening twilight towards the end of the year.

With all the prominent constellations in the early autumn sky, we tend to overlook the smaller ones. About three-quarters of the way from bright Deneb (at the top of the Northern Cross) to Altair (immediately recognizable by its two flanking stars, which give it the appearance of flying across the sky) find exquisite Delphinus the Dolphin (which looks like a hand with a finger pointing more or less southward), and Sagitta, the Arrow, which pretty much looks like what it is supposed to be. Why Delphinus was not called simply "Manus" (the Hand)," is a mystery that is unlikely ever to be solved.

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