MAY  2006

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507    MAY 7, 2006:   Goodbye Gemini

One of my favorite constellations is rapidly sinking in the west. When the Gemini Twins, Castor and Pollux, stand straight and tall like the Roman heroes they were, spring is rapidly dissolving into the warmer days of summer. At 10:00 p.m. from urban locales in early May, the Twins’ brightest stars look like cat’s eyes staring in the dark. Their spacing is a little closer than the Pointer Stars of the Big Dipper, and they shine with more intensity. To the right is fainter Castor, the mortal brother of immortal Pollux on the left. From rural locales their stick figures are impressive. Castor’s long neck and torso contrasted against his short, “amputated” legs almost suggests torture at the hands of an enemy force. Pollux, on the other hand, is proportioned more realistically, even through he is a bit bowlegged. One myth relates that with Rome surrounded by enemy hordes, Castor and Pollux rallied the army and citizenry and rescued the day by defeating the foe at Rome’s doorstep. During their triumph into Rome, the Gemini steeds drank from a spring by which Rome erected a magnificent temple where people swore oaths “by the Gemini.” If you’ve ever said, “By Jiminy, I’m going to do that,” you have sworn an oath like the Romans did “by the Gemini.” You may also have been a charter member of the Disney Club. It’s not hip vocabulary anymore. Mars and Saturn lurk near Gemini. Find Saturn by viewing left, three times the distance between Castor and Pollux. This week Mars lies below and about twice the distance between Caster and Pollux. During the next five weeks, Mars will rapidly overtake Saturn. On the evening of June 17, the pair will be positioned just over half a degree from each other, a splendid view through wide field scopes.

508    MAY 14, 2006:   The Spirit is Alive

Mars continues its sojourn across the western sky, heading towards a June 17 rendezvous with Saturn. This week Mars is in the west, slightly below and fainter than the bright star Pollux of the Gemini Twins. See the map included with this week’s web edition of StarWatch at the URL below. If you take the time to look at Mars, keep in mind that there are three NASA orbiters currently sending back data about the Red Planet, as well as the European Space Agency’s, Mars Express. In addition, there are two NASA Mars Exploration Rovers, Sprit and Opportunity, advancing across its surface. It is the rovers that fascinate me the most. I’ll focus on Spirit which landed in Gusev Crater, January 3, 2004, a depression which appeared to have been a lake in Mars’ distant past. Leading into Gusev was a sinuous valley apparently carved by liquid water. Within three weeks of touchdown, Sprit was already tantalizing scientists with the possibility of water formed compounds. By March 5, Spirit began finding other basaltic rocks which appeared to have internal crystals deposited by water. On the opposite hemisphere of Mars, Opportunity seemed to have literally set down near the edge of what was once a saltwater ocean, implying a long history of liquid water in this region. The scientific community was ecstatic. By December of 2004, Spirit had found conclusive evidence of minerals that could only have been formed in the presence of water. Currently, two full years after its primary mission ended, Spirit has traveled over four miles from its landing site and is currently hunkering down in a position where its solar cells can receive enough winter sun to keep its heaters operational and accomplish a little science too. The Spirit is still alive!

Drawing created by Gary A. Becker...

NASA photo...

509    MAY 21, 2006:   Titan Revisted

I have been hyping the approaching June 17 conjunction of Mars and Saturn during the last several weeks. Low in the west right after darkness, you’ll see the two cat’s eyes of Castor (right) and Pollux of the Gemini Twins. Mars, this week, journeys from slightly below Pollux to its left. On May 28, from left to right, Mars, Pollux, and Castor will be in a straight line with the distance between Mars and Pollux just slightly greater than the separation of the Twins. Saturn, because of its 29.5-year orbit around the sun, still lingers in the star pattern of Cancer, about three Gemini Twins to the left. An on-line map is posted with last week’s StarWatch article at the URL below. Last year, the world was applauding the phenomenal success of Huygens, the European Space Agency’s probe, which landed on Saturn’s largest moon, Titan. Huygens was piggybacked onto Cassini, NASA’s Saturn orbiter, which is still going strong gathering vital data on the Ringed World and its moons. Cassini continues to probe Titan with radar pulses that can be used to recreate images of its topography. Titan seems to possess few meteorite craters, which indicates a young surface that is continuously changing. Linear dune fields, called “cat scratches,” indicate a consistent wind pattern across these regions of Titan’s surface. Twisted drainage patterns, over a mile wide and 120 miles in length, suggest that Titan’s surface is also being eroded by liquids. In addition, there may be volcanic flows that ooze across the landscape. Water-rich compounds from a warmer interior may be the “lava” of these cryovolcanoes which spew onto a frigid surface, nearly 300 degrees below zero F. These factors imply that Titan may possess tectonic movements similar to Earth’s continental drift.

The Cassini spacecraft shows small, battered Epimetheus and smog-enshrouded Titan, with Saturn's A and F rings stretching across the scene. The dark lane in the rings is the Cassini Division, and it separates the A Ring from the B Ring. NASA photo...

510a  MAY 28-31, 2006:   Mars and Jupiter Close, Mercury Reappears

Mars continues to approach Saturn in the west as darkness falls, staying basically even with the Gemini Twin stars, Castor and Pollux. By week’s end, the gap between Saturn and Mars narrows to almost the field of view of most common binoculars. Use binoculars to scrutinize Mars’s approach toward Saturn. This will allow the daily change in the position of Mars to be distinguished against fixed background stars. A map was posted with the May 14 Web StarWatch at the URL below. If that’s not exciting enough, two new players enter the field to make western twilights even more stunning, the moon and Mercury. The moon’s appearance in this portion of the sky will be short-lived. Luna will be to the right of Mars on Tuesday and just above Saturn by Wednesday, providing novice observers from either urban or rural settings, with an excellent method of locating these planets. But it is the reappearance of the Messenger God, Mercury, low in the WNW, which is really fueling my observing enthusiasm. Mercury will be visible throughout the entire month of June, although during the beginning and end parts of the month, it will require very clear skies and binoculars to allow it to be distinguished from the bright sky background. At the beginning of the week a razor thin crescent moon, with plenty of earthshine, will stand above Mercury 40 minutes after sunset. Use binoculars and allow the cup of the crescent to point the way towards Mercury. If your western horizon is low enough and the air sufficiently transparent, Mercury should appear like a twinkling star less than a binocular field from the horizon. High-rise apartment dwellers with windows or porches facing west are prime observing locations. Mercury’s position improves during the next several weeks.

Mercury returns to the evening sky for a debut which will last all through June. Mercury could be seen on Sunday, May 28 near the tree tops (center-right) along with a moon less than two days old. Canon D20 photography by Gary A. Becker...

510b  June 1-3, 2006:   Mars and Jupiter Close, Mercury Reappears

Mars continues to approach Saturn in the west as darkness falls, staying basically even with the Gemini Twin stars, Castor and Pollux through the end of the week. By Saturday, the gap between Saturn and Mars has narrowed to almost the field of view of most common binoculars, which will allow observers to scrutinize more keenly Mars’s march towards Saturn. Binoculars will allow the daily change in the position of Mars to be distinguished against the fixed starry background, as well as the ever narrowing gap between Saturn and Mars. Their closest approach will be on the evening of June 17. A map showing the changing positions of Mars was posted with the May 14 StarWatch at the URL below. If that’s not exciting enough, Mercury enters the observing arena against the backdrop of an increasingly moon-drenched sky to make western twilights even more stunning. The Messenger God, known for its short debuts in the evening or morning, will be visible throughout the entire month of June. In fact on the evening of June 17, when Mars and Saturn will be closest to each other, Mercury sets at an unprecedented 10:18 p.m., only one minute shy of its setting on the preceding evening. By Saturday, Mercury will be about one binocular field of view above the WNW horizon about 45 minutes after sundown. Use binoculars to discern Mercury’s star-like appearance just to the left of the brightest portion of the horizon glow. If the air is sufficiently transparent, along with an uncluttered horizon, Mercury might even be visible to the unaided eye as daylight fades. City dwellers, especially those in high-rise apartments with windows or porches facing towards the west, are prime observing locations. Mercury’s visibility dramatically improves next week.