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.
