Astronomy news for the two weeks starting Friday, April 13,
2012.
The Moon starts the week off, on
Friday, April 13th, in its third quarter,
after which it fades through waning
crescent until it disappears into morning twilight, new phase
finally taking place the night of Friday the 20th. As it goes, the
Moon passes several degrees north of
Neptune on Monday the 16th, then similarly to the north of Mercury and
Uranus the night of Wednesday the 18th, not that any of these
are readily visible, but perhaps it's nice to know.
The planets themselves more than make up for the lack of lunar
passages. Bright Mars,
high to the south near the meridian at
10 PM in Leo to the east of Regulus, ceases its
http://projects.astro.illinois.edu/data/Retrograde/">
retrograde motion on Sunday the 15th. It thereafter once again
resumes its normal easterly trek against the stellar background.
You can watch the red planet until it finally sets around 4:30 AM.
Just six hours after the Martian event, Saturn goes through
opposition with the Sun, when it
rises at sunset, crosses the meridian at local midnight (1 AM
Daylight), and sets at sunrise. Thus up all night, the ringed
planet makes a fine sight coupled to Virgo's Spica, which
lies somewhat to the southwest.
Next up is brilliant, unmistakable Venus, which
continues to dominate twilight and early evening skies and does not
set until 11:30 PM Daylight, the planet making a magnificent spring
appearance. The night of Monday the 16th, it passes 10 degrees
north of Aldebaran in Taurus. Venus has an almost-exact
eight year cycle relative to Earth. We will thus get a similar
show in 2020. On the other side of the sky and night, Venus's
"inferior" (meaning closer to the Sun than we) partner Mercury goes
through a rather poor greatest western elongation relative to the
Sun on Wednesday the 18th, the little planet not rising until mid-
twilight and essentially invisible. Jupiter, moving
out of sight, sets just as twilight ends.
This is a fine season to admire the longest constellation of the sky, Hydra, the Water Serpent. It's
raggedly-circular head can be found just to the east of Procyon in Canis Minor, the figure also making the southern apex
of a triangle that includes the Sickle of Leo to the east and the bright pair Castor and Pollux in Gemini to the west. The constellation then continues
to the southeast, diving beneath ancient Crater (the Cup) and box-like Corvus (the Crow), until it finally ends southeast of
Spica (and currently Saturn).
