Photo of the Week. A morning cloud points toward
sunrise.
Astronomy news for the week starting Friday, April 20, 2007.
The week begins with the Moon in its crescent phase. Heading toward its
first quarter on the night of Monday,
April 23 (about the time of Moonset in North America), it will
finish the week in its waxing gibbous
phase. Look for the first quarter rather well above the ecliptic to the east of Gemini's Pollux and Castor. Passing
Venus after they both have set the night of Thursday the 19th,
the Moon will appear well above the brilliant planet to the west on
the evening of Friday the 20th. Just above the Moon, find Elnath, Beta Tauri, which makes the
northern horn of Taurus, the
Bull.
Even after the Moon moves on, the western evening sky will present
us with a fine sight. Venus, of course, tops everything. Moving
into the northwest, the planet not only does not set until after 11
PM Daylight Time, but will continue to set ever later for yet
another month. At the moment, it's making a fine triangle with
Taurus's Hyades (down and to the
left of the planet) and the Pleiades (down and to the right). On Saturday the
21st, Venus will pass seven degrees to the north of Aldebaran.
Saturn of
course also continues to make its mark. Passing the meridian to
the south shortly after sunset, by the time it is dark, the ringed
planet has moved into western skies. Look for Regulus to the east of it. The
night after the quarter Moon, that of Tuesday the 24th, the Moon
will make a fine sight just to the west of Saturn. The following
night finds it similarly placed relative to Regulus. As seen from
the far west, the Moon will actually occult the star the morning of
Thursday the 26th, the time ranging from about 2:25 AM Pacific Daylight
Time in the northwest to 2:55 AM in the southwest. Then as Venus
sets, Jupiter rises in the southeast to replace it,
the giant planet still to the northeast of Scorpius's Antares.
Mars still tracks the onset of dawn, making it hard to see.
The week features one of the better-known meteor showers of the
year, the Lyrids.
Appearing to emerge from the constellation Lyra, they reach a peak on the mornings of Sunday the
22nd and Monday the 23rd, when you might see up to 20 or so per
hour. They have been identified as the debris of the Comet Thatcher of 1861, which
has a period around the Sun of 415 years.
Among the great constellations of the sky is Argo, the Ship of the Argonauts, which is so large it
is now divided into Vela (the
Sails), Puppis (the Stern), and Carina (the Keel). Much of Puppis is
rather well visible southeast of Canis
Major. Vela (southeast of Puppis), however, requires a more
southerly observing latitude, while the glories of Carina (which
holds the second brightest star, Canopus) are best seen from the
southern hemisphere.
