Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. Cactus blooms pay homage to the
Sun and sky.
Astronomy news for the week starting Friday, February 25, 2005.
Skylights will next appear on March 11.
This issue of Skylights is dedicated to my mother, Hazel (Susie)
Kaler, who turns 100 today, February 25. Happy Birthday, with love
and thanks.
Our Moon begins the week in its waning gibbous
phase. Passing
third quarter on Thursday, March 3, it then
wanes through crescent to new on Thursday, March 10, giving us
dark skies as spring comes ever closer in the northern hemisphere.
As it moves along, the Moon takes on a planet and two stars. The
night of Sunday, February 27, it passes right beneath Jupiter
, and together with Virgo's
Spica will make a fine
configuration. The following night, Monday the 28th, continues the
show with the Moon to the left of both Jupiter and Spica. Watch
then as the crescent descends through Sagittarius on the morning of Saturday, March 5, with Mars to the left.
The following morning, the Moon will pass to the south of the red
planet, which now rises just before 4 AM. On Monday the 7th, the
Moon passes south of Neptune.
The big event, however, is an occultation by the Moon of the bright, red
supergiant star Antares, in Scorpius, on the morning of Thursday,
March 3, the event easily visible across the entire US (except
Alaska) and most of Canada. The exact time depends on where you
are. From the eastern US and Canada, the not-quite-full Moon will
pass over the star around 6 AM, in twilight (use binoculars), the
star disappearing behind the eastern (leading) lunar edge. The
rest of the country sees the event in darkness, around 4:40 AM CST,
3:20 AM MST, 2:15 AM PST, these times only approximate for specific
locations. The Moon moves its own angular diameter in about an
hour. The star will reappear from behind the lunar disk (at the
dark western edge) in twilight in the midwest, around 6 AM CST,
4:30 AM MST, 3 AM PST. In the east, re-emergence is in daylight
and not visible. Fun to watch, occultations clearly show the
easterly motion of the Moon, and also show that stars have terribly
small angular diameters, as they wink out and reappear almost
instantly behind the lunar edge. Precision instruments that
measure the time it takes the star to disappear and reappear allow
the measurement of angular diameter.
Saturn
now crosses the meridian high in Gemini at 9 PM, just about as Jupiter rises in the
southeast in Virgo. In the early evening, you might spot little
Mercury, which will be making a nice appearance toward the end
of this fortnight, as Friday the 11th closes in on us -- look due
west in mid to late twilight.
In mid-evening, Auriga and Gemini are high in the sky above Orion. Closer to the north celestial pole (around which the
stars seem to turn), Perseus and then Cassiopeia are slipping
silently to the west, and are slowly being replaced by Ursa Major's Big Dipper, which stands on its handle to the
northeast. In between is the pole itself, beautifully marked by Polaris at the end of the handle of
Ursa Minor's Little Dipper.
