MAY  2005

MAY STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

Print Large Sky Charts For 10 p.m. EDT:   NORTH | EAST | SOUTH | WEST | ZENITH

454    MAY 1, 2005:   Young and Old Moons

As the moon orbits the Earth and sweeps through its phases, there is a moment in time when its position is perpendicular to the plane of Earth’s orbit and the sun. This is called the new moon, and it begins the next phase cycle which lasts on average 29-1/2 days. Normally, there is an interval of three to five days when the moon simply seems to disappear from the sky because its rising and setting times coincide too closely with the sun. But the moon really is not entirely gone for that length of time. It is just a little more elusive. Regardless of whether the locale is urban or rural, the moon’s thin silvery sliver, accented with the ashen light of a nearly full Earth, can be an inspiration to witness, especially against the deepening twilight of a moist, spring evening or the stillness of a new and yellowing dawn. The trick to catching a very old or a very young moon lies in the steepness of the moon’s orbital path to your horizon, the clarity of the atmosphere, and how unobstructed your eastern and western views are. For mid-northern latitudes, astronomical conditions favor young moons for spring evenings, while autumn mornings are more conducive to enhancing the prospects of seeing a very old moon. The moon is new on May 8 at 4:47 a.m. You should be able to spot easily the old waning crescent moon low in the east on Thursday at 5:15 a.m. It might still be possible to see the moon on Friday, a few degrees off the eastern horizon at 5:30 a.m. Use binoculars. The star-like object to the right of the moon on Friday will be Mercury. It’s doubtful that you’ll see the very young moon in the WNW on May 8 about 15 minutes after sunset, but Venus should be visible through binoculars. The following evening, the young waxing moon will be an easy target by 8:40 p.m.

455    MAY 8, 2005:   Traveling Moon: Part 1

During the next several weeks I will be following the moon during its journey around the Earth. Each day, the moon changes its position by just over 13 degrees, which is a little more than its own diameter each hour. Night by night as the moon’s crawls along, it catches up to and passes various sky targets that are near its orbital path, allowing it to act as a tour guide for some of the brighter celestial bodies. The moon was new today about 4 a.m., but out of sight. Last month, you may recall the new moon made a dazzling appearance for some well-placed observers when it eclipsed the sun, and its shadow swept northeastward across the Pacific Ocean. That won’t happen this month, because the moon will be nearly three of its diameters north of the sun at the time of its new phase. You may not see the very young moon in the WNW tonight about 15 minutes after sunset, but nearby Venus should be visible through binoculars. On Monday, the young waxing crescent moon, about 40 hours old, will be an easy target 45 minutes after sundown. During the next three nights, Luna, reflecting back to us the ashen light of a nearly full Earth, will climb steeply into the evening twilight, its narrow crescent broadening into a wide grin. As twilight deepens on Thursday, the moon will appear to the right and slightly below Saturn. Above the moon, look for the two bright stars of the Gemini Twins, Castor (right) and Pollux. On Friday, the moon moves above Saturn, and it is to the left of Pollux and Castor. Below and left of Saturn will be Procyon, the brightest star of the Little Dog, Canis Minor. If you are out during deep twilight, that wildly twinkling star near the WSW horizon will be Sirius, the brightest star of the night, bidding us adieu until late next fall.

A 40-hour moon sets in the WNW in Coopersburg, PA on May 9. The star over the tree is Aldebaran, the principal luminary of Taurus the Bull. Gary A. Becker digital photo...

456    MAY 15, 2005:   Traveling Moon: Part 2

If you have been watching the moon during twilight over the last few evenings, you probably have noticed that it passed, late last week, a bright star like object in the west. That was Saturn. A few weeks ago in this column, I mentioned that Saturn had 34 natural satellites. That information has gone stale with the announcement of the discovery of 12 additional moons, according to the Giant Planet Satellite and Moon Page, bringing Saturn’s total to 46. Current statistics can be found at http://www.ifa.hawaii.edu/%7Esheppard/satellites/. All of the new moons are between 2.5 miles and 4.5 miles in diameter, chunks of debris captured by Saturn’s strong gravitational field and only visible using the most sensitive photographic techniques. Our moon during its 27.3 day circuit of Earth passes near all of the planets and many bright stars, making it an ideal way of locating them. Tonight and tomorrow, the moon passes through the Sickle of Leo, the Lion, which outlines his head and the front portion of his body. Monday, the moon sits above and to the left of Regulus, the brightest star of the Lion. Tuesday, it is below the triangle of stars that forms the hindquarters of Leo. You’ll need to occult the moon with your hand to see the triad or use binoculars. Now the moon has its sights set on Jupiter, the largest of the nine planets and only third to the moon in brightness. Thursday finds the moon only four of its diameters below Jupiter, a striking pair in the SE as darkness descends. Use binoculars to enhance this dazzling view against a darkening blue sky. By Friday, the moon has appeared to leap from Jupiter to just left of Spica of Virgo the Virgin, the 15th brightest star of the night. Saturday’s nearly full moon is in the SE below Spica.

457a  MAY 22-23, 2005:   Antares Occultation

For the last two weeks I have been following the moon in its orbit around the Earth allowing it to act as a tour guide, pointing out the interesting stars and planets along the way. The moon is full on Monday about 4:40 p.m., and as such, it will rise in the southeast shortly after sundown, flooding the sky with light and making nearby objects almost impossible to view unless they are very bright. Enter Antares, the rival of Ares (Mars), a red supergiant star which will be visible to the left of the moon when it rises, Monday. Antares, the 16th brightest nighttime star, is the principal luminary of Scorpius the Scorpion. You can make seeing Antares easier by simply occulting the moon with a finger. Use binoculars to enhance Antares reddish hue. At 10 p.m. the moon and Antares will be just shy of three degrees apart. As the night waxes, the moon will steadily gain on Antares, moving its own diameter each hour. By 4:00 a.m. EDT Antares will be less than one half degree from the moon, but the moon will only be 13 degrees off the SW horizon. Minute by minute, the moon will steadily gain on Antares, but the Earth’s rotation will also move the moon and the star closer to the horizon. At 4:20 a.m. EDT, Antares will be occulted by the moon only 11 degrees off the SW horizon. Binoculars or a small telescope will be needed to view the actual event. The farther west one goes, the higher the moon will be in the sky, and the earlier the occultation will occur. In Los Angeles, for example, Antares is occulted about 11:57 p.m. Monday. On June 9, 1968, the night that I graduated from Allen High School, I remember rushing home to set up my telescope in the backyard to catch a near occultation of Antares and the moon. This one will be much better.

457b  MAY 24-28, 2005:   Catch a Falling Star

The sign read, “There is something in this room that is 4.8 billion years old, and no, it is not your teacher.” Most of my Allen students missed it as they filed in saying their hellos as I took roll by the door. So I removed it and taped it up again, my fist making a dull thudding sound as I pounded on a wooden cabinet, attempting to get the district-issued tape to stick for a second time. But then the questions began. Was it the air? That was actually an excellent start. Certainly, some of the atoms of hydrogen contained in the water vapor that we were breathing had to be as old as the universe itself, 13.7 billion years. But I was talking about something tangible, something you could touch and hold in your hand. It didn’t take long for my pupils to figure out that I was wearing an odd-looking pendent, something that had shiny metal mixed in with a yellowish green mineral. A few more questions followed, but it was Anthony Corona that solved the puzzle. He said, “Is that a meteorite?” And indeed it was. I had just purchased a beautiful thin slice of the large Brahin pallasite (stony-iron) which was first discovered near Minsk, Belarus (Eastern Europe) in 1810. Very small sections of the meteorite had been made into pendants, and there was one of them, a beautiful stony-iron gem, calling to me behind a glass display case. I couldn’t resist. This “fallen star” was a tiny piece of a much larger asteroid that had collided with another body, billions of years ago. Its shattered remains began traveling in a myriad of new orbits around the sun. One day, a small member of that original body intersected the Earth, and the result was a rain of debris near the town of Minsk. Now, nearly 200 years later, I was wearing a survivor of 4.8 billion years of solar system history. What a thrill!

Minsk, Belarus is the location where pieces of the Brahin meteorite were discovered in 1810.

458    MAY 29, 2005:   On the Beach

I just returned from the Southwest with a contingency of 16 wonderful Dieruff H. S. students. The purpose of the field experience was to explore the astronomy and ecology of the Four Corners region where Utah, Colorado, Arizona, and New Mexico join. We hiked the volcanic Malpais west of Albuquerque, NM, spent three days learning about the Ancestral Puebloans of Chaco Canyon (NM) and Hovenweep (UT), and hiked up to Delicate Arch in Arches National Park (UT) by moonlight. The showstopper, however, was a four day whitewater rafting trip down the kicking Colorado through Cataract Canyon, part of Canyonlands National Park. I have always joked that I was a clean camper. I liked my tent, pillow, air mattress, sleeping bag, and especially my evening showers, preferably hot. Well, it was a little different on the sediment filled Colorado—more primitive—but at the same time more pristine. Towering red-burnt canyon walls began to shadow the daylight as early as 5 p.m.; and there was always the river—chortling, surging, and cajoling you to follow its path. The third night was by far the most memorable. We were camped in the Big Drop where the Colorado raced as it descended 38 feet during the course of one mile. The din of cascading water could be heard both up and downstream. Waves broke on an eroding shoreline as the brown Colorado surged from recent snowmelt. I slowly descended into a deep sleep under the stars of that sand beach, soaking in the moon-splashed canyons, amidst the call of the water, and watching the familiar Big Dipper wheel overhead against the backdrop of high, wispy, cirrus clouds. On that magical evening under the stars, a hot shower would have been an imposition.

On the beach in moonlight in the Big Drop section of Cataract Canyon, Canyonlands National Park, Utah... Gary A. Becker digital photo...

Moonlight illuminates the Colorado River in the Big Drop section of Cataract Canyon. Gary A. Becker digital photo...