Photo of the Week. High cirrus is set into an
ultra-blue sky as seen looking up from 30,000 feet.
Astronomy news for the week starting Friday, April 9, 2010.
Our Moon disappears
this week. Starting with a very visible morning waning crescent, it finally goes through
its new phase on the morning of Wednesday, April 14. Your last
view of it, though, will be the morning of Monday the 12th, as on
the 13th it will be too thin to view in morning twilight. The
morning of Sunday the 11th, it will shine to the northwest of Jupiter, which
is only barely visible in dawn's light, while by the following
morning the Moon will have flipped to the other side of the giant
planet, which does not even rise until halfway between the onset of
dawn and sunrise. The neighborliness of the Moon and Uranus on Monday
the 12th (the Moon to the north) is quite invisible (but at least
we know the distant planet is there).
The evening presents a better sight. Mercury is doing quite
well, and is in fact going through one its better aspects of
visibility. The twilit evening of Thursday the 15th finds the thin
waxing crescent directly above the little
planet, making it fairly easy to find since it sets about as
twilight draws to a close (around 9 PM Daylight Time). But you
also get a fine bonus here, as up and to the left of the Moon you
can spot Venus, which after the Moon itself will be the brightest
thing in the sky. The trio will make a lovely set well worth
finding a decent horizon for. Just look early enough in mid-
With Jupiter, Venus, and Mercury out of the way, that leaves us
with Mars and Saturn, not a bad duo to be stuck with.
Night after night shifting slowly to the west, Mars now transits
the meridian to the south in mid-
twilight. The planet is still in Cancer to the northwest of the Beehive cluster, between it and the Pollux-Castor pair in Gemini and about as far north of
the celestial equator as it can get. It will
pass north of the Beehive on Friday the 16th.
Saturn, still in Virgo about two
and a half degrees north-northeast of the Autumnal Equinox, then transits about 11:30 PM Daylight,
while we wait for Mars to set at 3:30 AM, followed an hour and a
half later by Jupiter rising.
To east and southeast of Canis
Major (marked by brilliant Sirius), vast Argo, the Ship of the Argonauts, floats on the "wine
dark sea." Puppis, the section of
Argo that represents the Stern, lies above more southern Carina, the Hull, while Vela the Sails flap well to the east.
If you live far enough south in the southern tier of States, look
for Canopus, the sky's second
brightest star, well below Sirius.