Saturday, April 14, 2012

Planets and Falling Stars

Drive a spike to Spica – and Saturn – in springtime 2012 A Pacific front is expected here by Monday! With the last quarter moon rising much later, darker nights and maybe a few clear nights, we might have a chance to observe, this third week of April....

Saturn (magnitude +0.2, in Virgo) It rises in twilight and glows highest in the south around 1 a.m. Shining 5° to its right is Spica: fainter, bluer, and twinklier. Watch for a temporary brightening of the rings with respect to the globe. This happens because the solid particles making up the rings backscatter sunlight (reflect it back in the direction it came from). Saturn is at opposition, opposite the Sun this Sunday, April 15. It rises around sunset, shines highest in the middle of the night, and sets around sunrise.

MARS (magnitude –0.4) shines fire-orange in Leo. Regulus is 4° to Mars's right in early evening, and fainter Gamma Leonis is 7° above it. Look for them high in the south. Mars ends its retrograde (westward) motion for the year and resumes heading east against the background stars. Watch it pull away from Regulus in the coming weeks: slowly at first, then faster.

By the end of the week, Saturday, our New Moon rises (exact at 3:18 a.m. EDT on the 21st).

The unpredictable Lyrid meteor shower should reach maximum activity in the hours before dawn Sunday morning. There will be no Moon. Expect the shower to peak on April 21-22; a nearly-new moon on those dates will provide perfect dark-sky conditions for meteor watching. Usually the shower is mild (10-20 meteors per hour) but unmapped filaments of dust in the comet's tail sometimes trigger outbursts 10 times stronger.

News from the Net:
Weekly SkyWatcher’s Forecast – April 16-22, 2012
Shuttle Discovery Mated to 747 Carrier for her Final Flight to Smithsonian Home
NanoRacks and CASIS Put Research on the Universe’s Front Porch
New Evidence For Fomalhaut Planets
Scientists Suggest Evidence of Recent Lunar Volcanism
See Big and Bright Saturn at Opposition This Weekend
Thin Skinned and Wrinkled, Mercury is Full of Surprises
Hubble Reveals Curious Auroras on Uranus
Is This Proof of Life on Mars?

Friday, April 6, 2012

Full Grass Moon

Tonight’s Full Moon is popularly known as the Grass Moon, Egg Moon, or Paschal Moon. As the first Full Moon to fall after the vernal equinox, it fixes the dates of Passover for Jews and Easter for Christians. This Spring continues to be much greener and wetter than the past couple of years! The grass is high and lush as we move into the second week of April, with darker nights ahead, there should be several clear nights to observe... fingers crossed!

I observed Venus near the Pleiades twice this past week. Both nights, Venus was very close to the handle of the cluster. In binoculars, "the dipper" stars (6) were dim but visible. Venus is now at the peak of her best visibility. On clear nights you can easily follow Venus down toward the northwest horizon, where she sets well after 11:30 pm. As bright as she is right now, she will become brighter as the month passes, ultimately reaching a blazing -4.7 magnitude by mid-April. The bright star high to the upper right of Venus these evenings is Capella, the Goat Star. It's the same yellow-white color, and thus the same temperature, as the Sun. With the Moon gone from the evening sky, it's deep-sky observing time again. Telescope users are familiar with the "Leo Trio" of galaxies (M65, M66, and NGC 3628) by the little chair asterism in the back leg of Leo. Also near the back leg of Leo is the asteroid 5 Astraea, about magnitude 9.6.

Next Friday, the 13th, is the Last-quarter Moon (exact at 6:50 a.m. on this date EDT).

The red planet has faded by half a magnitude. Each passing day adds another 4.5 million miles of space between Earth and Mars, and in a few more weeks it will be difficult to discern much detail on his distant face. Fortunately we have a number of robot explorers circling the planet and parked on its surface, and in August the Mars Science Laboratory rover should reach its objective and land softly in a crater named Gale.

Saturn (magnitude +0.2, in Virgo) is at opposition April 15th. This week it rises almost around sunset and stands highest in the south around 1 or 2 a.m. daylight-saving time. Shining 5½° to Saturn's right is Spica. Saturn meets up with the Moon on the evening of the 6th, almost lost in Luna’s glare. The ringed planet is just over a week away from opposition, and he now beckons for telescopic attention during the later evening hours. The planet’s rings are now tipped 17 degrees to our line of sight, and they haven’t been this "open" to view since early 2007.

News from the Net:
1981 Climate Change Predictions Were Eerily Accurate
The Sun Does a Barrel Roll
Mars’ Giant Dust Devil in Motion
Could There Be Life In Them Thar Pits?
Astrophotos from Around the World of the Venus-Pleiades Conjunction
New Gigantic Tornado Spotted on MarsTimelapse: A Tribute to Sky Gazers