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The Sky This Week, 2013 February 26 - March 5

Lost in the clouds.
M42_120125_02_filtered_small.jpg

The Great Nebula in Orion, Messier 42
Imaged 2012 JAN 25 from Alexandria, VA
with an 80mm (3.1-inch) f/6 Antares Sentinel refractor
and a Canon EOS T2i DSLR


The Moon lights up the late-night sky early in the week as she wanes toward Last Quarter, which occurs on March 4th at 4:53 pm Eastern Standard Time. She begins the week among the stars of Leo, the Lion, then dives southward along the Ecliptic toward the rising stars of early summer. Look for her less than a degree south of the bright star Spica as she rises on the night of the 28th. During the early morning hours of March 2nd she forms an attractive triangle with golden Saturn and the second-magnitude star Zubenelgenubi in the constellation of Libra, the Scales. She wraps up her weekly travels among the stars of Scorpius.

As the Moon passes into the morning sky she leaves behind the stars of the Great Winter Circle for one final good viewing period in the evening sky. As March rolls in the length of daylight now rapidly erodes the early evening hours of darkness, and the winter star patterns seem to hasten toward the west as the calendar passes by. The bright stars of Orion and his companions now straddle the meridian at the end of evening twilight, leaving just a few hours to explore their cosmic treasures with binoculars or a small telescope. Orion is a wonderful constellation to peruse with these instruments. From the beautiful pastel hues of his brighter stars to the misty swatch of light that betrays the Great Nebula in his sword, Orion offers many delights for not only the novice but the experienced observer as well. If you’re in a dark location the Great Nebula will reward the patient viewer with just about any kind of instrument. In binoculars it appears as a fuzzy patch surrounding a tight knot of stars, bracketed by two bright clusters of icy-blue suns. A small telescope will reveal the Trapezium, a group of four stars in the nebula’s heart whose intense ultraviolet radiation causes the nebula to glow. Larger telescopes reveal more detail still; the view through my 14.5-inch reflector shows an eyepiece field filled wisps, knots, and streamers of glowing gas interspersed with dark rifts of opaque stardust. Here and there faint traces of color may be seen in the most intense glowing clouds. The impression is both dynamic and steadfast, as if a vast swirl of material is frozen in time. This is, in fact, a very dynamic place where star formation is taking place at breakneck speed on the cosmic scale. The stars of the Trapezium, the youngest stars in the nebula, "switched on" less than a million years ago. The nebula is the brightest part of a vast network of interstellar clouds that lies behind the constellation. Long-exposure wide-field images show a huge "bubble" of faintly glowing gas surrounding the Hunter’s familiar shape. If we could view our Milky Way Galaxy from a million light-years distance the stars and gas clouds of Orion would be one of its most striking features.

The two most striking features of our solar system now share the late-night sky for a few short hours. Jupiter dominates the early evening sky while Saturn holds court in the early morning hours.

Jupiter is still the brightest planet in the sky, becoming visible high in the south shortly after sunset. As evening twilight fades he begins to heel toward the western horizon where he now sets at around 1:00 am. You have until about 11:00 pm to train the telescope on him before he settles into the turbulent air over the horizon, and the view through almost any telescope will be a rewarding one. Small instruments easily show his four bright Galilean moons, while larger instruments allow you to pick out subtle details in his ever-changing cloud bands. The evening of March 1st is a particularly good time to check him out; the famous Great Red Spot will be transiting the Earth-facing side of the planet while the moons Io, Europa, and Ganymede seem to converge on Old Jove’s disc.

Saturn rises at around 11:00 pm as the week opens, and he should be high enough in the southeast to view by the time Jupiter sets. Saturn’s disc is more bland than that of his jovial rival, but the planet’s rings more than make up for the lack of planetary detail. They are visible in any telescope, but every step up in telescope aperture will reveal more details. Some of my favorite views have been with a home-built 8-inch reflector that not only gives a crisp view of the rings but also reveals a sprinkling of small moons surrounding the distant planet. I’m looking forward to getting re-acquainted with this distant world as the warmer nights of spring approach.

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