Photo of the Week. A still, calm ocean reflects the
sky.
Astronomy news for the week starting Friday, October 17, 2008.
The
Moon moves out of the way this week, giving us a chance to see
the evening stars. Starting off in the last stages of the waning gibbous, the Moon moves through its third quarter the morning of Tuesday, October
21, shortly before sunrise in most of North America. The remainder
of our week sees the waning crescent
descend morning-by-morning toward the eastern horizon.
The morning of Saturday the 18th finds the Moon near its most
northerly possible position (given its five degree orbital tilt
against the ecliptic) in between classical Taurus and Auriga,
while the morning of the third quarter (Tuesday the 21st), the Moon
will visit Gemini just to the
southeast of Castor and Pollux. Then take a look the morning
of Friday the 24th to see the waning crescent in a lovely pre-dawn
position between Leo's Regulus and
Saturn, which is now eminently visible to the southeast of
Regulus as morning twilight approaches.
Moving inward in the Solar System from Saturn,
Jupiter is still beautifully visible in early evenings in the
southwestern sky to the northeast of classical Sagittarius. Look fairly early, as the giant planet
now sets shortly before 11 PM Daylight Time. Farther inward,
indeed inside the
Earth's orbit, are
Venus and then
Mercury, the first in the evening sky, the second in the
morning. Now moving quickly higher, Venus does not set now until
the end of evening twilight -- look for its obvious glow in growing
southwestern dusk. Back into the morning, the innermost planet,
Mercury, hits its greatest western elongation on Wednesday the 22nd
for some of the best viewing of the year. In contrast to Venus's
end-of-twilight setting, Mercury will rise (well to the east of
Saturn) just as dawn begins to light the sky.
One of the year's better
meteor showers is upon us this week, the Orionids, which peak
the morning of Tuesday the 21st. The Orionids are one of two
showers produced by the flakings of
Halley's Comet, the other the Eta Aquarids of early May. Ordinarily, the
Orionids produce some two dozen or so swift meteors an hour that
come roughly from the direction of northern Orion. The quarter Moon, however, will blot out the
fainter ones and cut the take a lot. They are still worth a look
both at the peak date and a bit before and after.
While admiring the Summer
Triangle of Deneb, Vega, and Altair now in the western evening
sky, don't forget to look for a pretty pair of other figures in the
area. About two-thirds of the way from Deneb to Altair find Sagitta, the Arrow (which really
does resemble what it is named for). To the southeast of Sagitta
swims Delphinus, the celestial
Dolphin, which more resembles a hand with a finger pointing back to
Altair's Aquila.
