Steamboat Springs Jimmy Westlake's 2012 Cosmic Calendar of Celestial Events
This year promises to be one of the most exciting years in recent memory for sky watchers. There are solar and lunar eclipses, a rare transit of Venus, conjunctions of bright planets and showers of falling stars to keep us looking up all year long. No optical aid, other than a safe solar filter, is required to view and enjoy these events, though binoculars or a small telescope could help to enhance the view. So check out my list of highlights for 2012.
Mars at opposition: Once every 780 days, the Earth passes in between Mars and the sun, placing the two planets as close together as possible. This alignment of worlds is called opposition. When Mars reaches opposition on March 3, it will be 63 million miles from Earth, its closest point for 2012. On the night of opposition, dazzling red Mars will rise in the eastern sky at sunset while three of the four remaining naked-eye planets plus the moon share the stage.
Turn your back on Mars and look west as the sunset glow fades from the sky. There you will see the twin beacons of Venus and Jupiter lighting up the night. Venus is the brighter of the two. Below them and closer to the horizon, you also can spot the elusive planet Mercury until about 7:30 p.m. Overhead, the 10-day-old moon shines down brightly. Draw an imaginary line in the sky connecting these celestial dots — Mercury, Venus, Jupiter, the moon and Mars — and you will have traced out the ecliptic, the heavenly highway that the sun, moon and planets follow around our sky.
Venus meets Jupiter: During the first two weeks of March, our evening sky is swarming with bright planets — Mars in the east and the Jupiter-Venus pair in the west. Because they are so bright, these planets are the first “stars” to pop out in the night sky, but unlike the fixed stars, these planets move around relative to one another and against the background stars, something that you can easily observe this month. As March begins, Jupiter hovers 11 degrees above Venus in the western sky — about the width of your fist held out at arm’s length — but that gap shrinks by nearly a degree each night until, on March 13, the two brightest planets in the sky will shine only 3 degrees apart. Wow!
An annular solar eclipse: Not since May 10, 1994, has a central eclipse of the sun been seen from the 48 contiguous United States. It has been a long drought, but come May 20 this year, folks living in the southwestern U.S. will have their chance when the moon passes in front of the sun, partially blocking its light from reaching us. This eclipse is an annular or ring eclipse because the moon will be too far from Earth to completely cover the sun. Instead, a thin annulus or ring of sunlight will surround the moon at maximum eclipse. While certainly rare and spectacular to see, an annular eclipse is not as magnificent as a total eclipse of the sun. At no time will the sun be completely hidden from view and safe to observe without a proper solar filter.
For Northwest Colorado, the eclipse will be off center and only 85 percent of the sun will be covered. The eclipse begins at 6:23 p.m. when the moon takes its first little nibble out of the lower right edge of the sun’s fiery disk. Maximum eclipse occurs at 7:30 p.m. Viewing the eclipse safely will require a #14 welder’s glass or an aluminized Mylar filter, available commercially from many sources of telescope and photography equipment. This year’s annular eclipse is just a warmup for the incredible total eclipse of the sun coming our way in August 2017.
A partial lunar eclipse: In an eerie re-creation of last December’s sunrise lunar eclipse, the full moon once again will slip into the Earth’s dark shadow by the dawn’s early light on the morning of June 4. This eclipse, however, will not be total for anyone on Earth. It is a partial eclipse of the moon, which means that the moon’s path takes it through the edge of the Earth’s shadow only. June’s full Flower Moon will rise at sunset on the evening of June 3 and will show no hint of an eclipse until just before 4 a.m. the next morning. That’s when the lower-left edge of the moon will begin to darken as it enters the Earth’s umbral shadow. Then, it becomes a race against sunrise as dawn brightens the sky. Maximum eclipse happens at 5:03 a.m.
If you have a very clear view of the southwest horizon, you might be able to follow the eclipsed moon all the way to its setting point. Binoculars will help. The next umbral lunar eclipse visible from Colorado will be the total lunar eclipse of April 15, 2014.
A transit of Venus: “By far the noblest (sight) astronomy affords.” That’s how Sir Edmund Halley described one of nature’s rarest astronomical events — a transit of the planet Venus across the face of the sun. It is, in effect, a miniature version of the annular eclipse of the sun seen last month. Even more rare than the once-every-76-year passages of Mr. Halley’s comet, transits of Venus occur in pairs separated by an average of 120 years. The two transits in each pair are eight years apart. There were no transits of Venus in the 20th century, the previous pair happening in 1874 and 1882. The transit of June 8, 2004, was the first since the Victorian era and, unfortunately, was visible only from the eastern half of North America, bypassing Colorado.
The good news is that the second in the current pair of transits on June 5 will be visible from the entire continent. The transit begins in Northwest Colorado at about 4:10 p.m., when the dark edge of Venus will take a tiny bite out of the edge of the sun. Mid-transit occurs at 7:30 p.m. with the sun only 10 degrees above the WNW horizon, and then the sun will set for us at 8:34 p.m. with Venus still silhouetted against the sun’s blinding face. Like eclipses of the sun, at no time will the transit of Venus be safe to view without a solar filter. The tiny black disc of Venus is barely large enough to be seen with the unaided eye through a proper solar filter, but a filtered telescope will provide the best view. You also can use your unfiltered telescope as a projector to cast an image of the sun safely onto a wall or white card positioned behind the eyepiece, but you should never leave such a set-up unattended such that children or others might attempt to look into the eyepiece at the sun — instant blindness could result.
Anyone who misses the transit of June 5, 2012, will never get to see another one. The next pair won’t happen until 2117 and 2125.
Curiosity lands on Mars: Exploring other planets is cool, and it gets even cooler Aug. 6 when NASA’s SUV-sized automated roving vehicle named Curiosity is scheduled to land on the Red Planet and begin searching for hints of Martian life. Officially called the Mars Science Laboratory, or MSL, Curiosity began its journey to Mars last Nov. 26 atop a powerful Atlas V rocket, but it will take 8 1/2 months to coast to Mars. Once there, a parachute will help to slow the speeding craft until a hovering “sky crane” can lower the massive rover to the Martian surface on a tether. This new landing technology never has been tried on another planet, so these will be some tense, nail-biting minutes until we know that the rover has its wheels safely on the Martian dust.
Also new to this mission is the super-rover’s power supply. Unlike previous rovers that utilized solar panels to collect energy from the sun, Curiosity carries its own miniature nuclear power source that will allow it to do more science and move around a lot more. What will Curiosity discover on Mars? No one knows.
Perseid meteors, Venus, moon and Jupiter in the predawn sky: The August Perseid meteor shower is one of the most reliable of our annual meteor showers. We experience this shower of “falling stars” every Aug. 11 and 12 when the Earth plows head-on into the dust swarm left behind by a comet named Swift-Tuttle. If the sky is dark and clear, a single observer usually can count about 60 meteors per hour during the shower’s peak before dawn Aug. 12. But don’t expect to see exactly one meteor per minute. The Perseids shoot across the sky in brief flurries of two or three with several minutes of calm in between. The meteors will seem to spring from the constellation of Perseus, the Hero, hence the name of this shower.
Perseid meteor watching makes a great family activity. Take the kids and find a nice, dark campground, roll out the sleeping bags and watch the fireworks. See who can count the most meteors or who can spot the brightest one. This August, the 24-day-old moon will rise around 1:30 a.m., sandwiched in between the dazzling planets Jupiter and Saturn, but its thin sunlit crescent shouldn’t interfere with watching dozens of meteors shoot across the sky.
Jupiter at opposition: Jupiter wears the crown when it comes to ruling the midnight sky, and Jupiter will be at its closest point to Earth, and thus brightest in our sky for 2012, on Dec. 2 when it reaches opposition. For a few weeks around that date, Jupiter will rise in the east as the sun goes down in the west and will gleam brilliantly from high overhead in our midnight sky. On the night of opposition, Jupiter will be a mere stone’s throw from Earth — about 380 million miles. Steady binoculars or any small telescope will reveal Jupiter’s four traveling companions, discovered by Galileo in 1610. They are Io, Europa, Ganymede and Callisto — the four largest of Jupiter’s 63 known moons. Watch from night to night as the moons constantly change their positions around Jupiter. With a medium-sized telescope, you also can see the two main cloud stripes straddling Jupiter’s equator and maybe even the famous Great Red Spot. As a prelude to the opposition, don’t miss dazzling Jupiter rising only 1 degree from the full moon Nov. 28.
The Geminid meteor shower: There’s been a lot of talk recently about the annual Geminid meteor shower becoming stronger and stronger each December since it was first observed in 1862. Geminid meteors spring from our constellation of Gemini, the Twins, and seem to be associated with the asteroid or burned-out comet named Phaethon. The nearly full moon ruined the Geminid meteor shower in 2011, but observer reports from across the world revealed that the peak of the Geminid meteor shower exceeded even the most optimistic predictions as meteors were shooting across the sky at a rate of more than 120 per hour. If that trend continues, the Geminids could become our most active annual shower in the coming years. In 2012, the moon will be new on the morning of Dec. 14, leaving the sky dark and moon-free during the best meteor-watching hours before dawn. So bundle up against the cold, break out the hot cocoa and enjoy the best meteor shower of 2012.
All year long
The active sun and the chance for an auroral storm: Nothing that I have ever observed in nature can top witnessing a vivid display of the northern lights. It is a jaw-dropping, knee-wobbling experience. Seeing them from Colorado is uncommon, but not rare. The trick is knowing when and where to look. This year, as the sun ramps up toward its once-per-decade maximum in activity expected in late 2013, our chances of a powerful geomagnetic storm sending auroras our way improve greatly. Auroras tend to cluster around the March and September equinoxes for some unexplained reason, and reach a fever pitch in the hours around midnight, while most folks are snug in their beds unaware of the spectacle unfolding outside. You can arrange through www.space
weather.com to receive an automated telephone call to awaken you in the night in the event of an auroral storm in your area. It doesn’t get any sweeter than that! So stay alert, and I’m betting that once or twice in 2012, the northern lights will come our way and give you that jaw-dropping, knee-wobbling experience, too.
Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus.