Scarps and craters on the surface of Mercury
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M A R C H S K Y W A T C H Mercury is back in sight again! It’s not that Mercury is so spectacular. It’s just that elusive Mercury is hard to see. It is small, and it hangs out close to the Sun, whose huge field of light obscures it. This means that we see it only sometimes, and only about 45 minutes after sunset, or before sunrise, and always close to the horizon, where atmospheric dust and interference is strong. Well, this is the month to see Mercury. It makes its best evening appearance of 2005. Look low in the deep orange twilight sky for a bright dot. There is no bright star near to confuse the viewer. Mercury will turn retrograde this month, and in this process it moves away from the Sun. Thus it appears to climb higher and higher in the western twilight, until March 12. (It’s interesting that the general energy of March shows a building-up until March 14, and a great series of changes during the second half of the month, just as Mercury is becoming fainter and more invisible.) The best night to view Mercury is March 11. As always with Mercury, we have to be quick to catch it. Begin looking at the western sky a half hour after sunset as you acclimate to the dark. Soon you will see the dramatic, delicate, razor-thin new moon. Down a bit and to the right, look for the bright yellowish "star," which is Mercury. Notice setting Cassiopeia (the big M) up and to the right of Mercury. It can help us to peg Mercury’s location on other nights, when we don’t have the help of the Moon, and as Mercury becomes fainter. Saturn is still bright during March. Around 9 p.m. local time, it lies due south. Saturn appears a bright golden "star." It rises a bit earlier as the month wears on, but remains close to the Gemini Twins, where it has been for weeks. Saturn sets about 4:30 a.m., which is about the time Mars rises. Remember, they are opposite this month, exact on March 7. You can look for that opposition, with Mars rising, about an hour before sunrise. Again, the crescent moon can point to a magical view of Mars. Now we have the balsamic, or dying, moon, rather than the fresh new moon. About 5 a.m. on the morning of March 6, it will look like the crescent is holding Mars. Antares, the bright orange star of Scorpio, is off a ways to the right. Their colors match, but Antares shines its own hot orange, and Mars reflects the light of iron compounds. I want to notice how we use Mars energy now. Tomorrow Mars opposes Saturn, a significant aspect. Jupiter, our most radiant planet, rises around 9 p.m. local time. It thus shines brightly the entire night. It is close to Virgo’s bright blue star, Spica. On March 25, Jupiter is close to the full moon. Venus rises with the Sun, and is now too close to the Sun to see. But do look for the special treat of Mercury in the evening sky! |
