THE SKY IN MARCH 



By Joe Rao 



Mercury lies low in the western sunset 

 sky during the first several days of 

 March, shining at magnitude 0.8. On 

 the evening of the 1st the planet sets 

 nearly due west about eighty minutes 

 after sunset. It is situated slightly more 

 than ten degrees below and to the 

 right of a young crescent Moon; a 

 clenched fist, held at arm's length, 

 measures roughly ten degrees, and so 

 Mercury should be slightly more than 

 one fist below and to the right of the 

 crescent. The planet passes inferior 

 conjunction (between the Earth and 

 Sun) on the 12th and spends most of 

 March in the glare of the Sun. Late in 

 the month, however, it slowly 

 reemerges low in the eastern 

 dawn. 



Venus is the brilliant morning 

 "star" that rises in the east-south- 

 east at about 4 A.M. all month. 

 The glimmering of Venus is a 

 harbinger of daybreak, which ar- 

 rives less than an hour after the 

 planet rises. During March, 

 Venus dims a bit and loses a lit- 

 tle altitude. It reaches greatest 

 western elongation (46.5 degrees 

 from the Sun) on the 25th. 



Mars makes its appearance as an 

 extra, first-magnitude "star" in 

 the constellation Taurus, the bull. Late 

 on the evening of the 5th you'll see 

 Mars dropping in the west-northwest 

 sky side by side with a fat crescent 

 Moon. Drifting eastward on the 10th, 

 the planet passes seven degrees north 

 of Aldebaran, which, at magnitude 0.9, 

 is the brightest star in Taurus. That 

 night, the brightness and orange hue 

 of the planet and the star are about the 

 same. By month's end, Mars lies be- 

 tween the horns of Taurus and fades to 

 magnitude 1 .2. 



Jupiter, in the constellation Libra, the 

 scales, rises at about 11:15 KM. on the 

 1st and two hours earlier by the 31st. 

 An hour or two after rising, the plan- 

 et is well up in the southeast. The best 

 time for observingjupiter with a tele- 



scope is early morning, when it reach- 

 es its highest altitude. 



Saturn is in an excellent position for 

 early evening observing; it crosses the 

 meridian at about 9:45 P.M. on the 1st 

 and two hours earlier by the end of the 

 month. On the evening of the 10th 

 the waxing gibbous Moon is situated 

 to the east of Saturn. The zero-mag- 

 nitude planet lies within the bound- 

 aries of the faint constellation Cancer, 

 the crab — a star pattern so dull that 

 Kenneth L. Franklin, who for many 

 years was chief astronomer at the Hay- 

 den Planetarium in New York City, 

 referred to it as an "empty space" in 





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Path of totality for total solar eclipse on March 29 



the sky. Saturn's beautiful ring system 

 is inclined about nineteen degrees to 

 our line of sight. 



The Moon reaches first quarter on the 

 6th at 3:15 p.m. and waxes to full on 

 the 14th at 6:35 P.M. It wanes to last 

 quarter on the 22nd at 2:1 1 P.M. and 

 becomes new on the 29th at 5: 1 5 A.M. 

 Early risers on the 22nd might note 

 how low the Moon appears in the sky 

 as it crosses the meridian, its highest al- 

 titude of the night, just before 6 A.M. 

 The low altitude is the result of its ex- 

 treme southern declination, an occur- 

 rence related to the so-called regres- 

 sion of the lunar nodes (the orbital 

 plane of the Moon wobbles like a top 

 with respect to the plane of the Earth's 

 solar orbit), a cycle that lasts 1 8.6 years. 



A penumbral lunareclipse takes place on 

 the 14th: the full Moon passes through 

 the penumbra, or outer portion, of the 

 Earth's shadow, causing a faint partial 

 shadow to fall on the Moon's surface. 

 The penumbra is usually hard to see, 

 but during this event it will cover the 

 entire Moon, noticeably tarnishing the 

 Moon's lower limb. Maximum eclipse 

 takes place at 6:47 P.M.; the penumbra's 

 grayish hue should be evident for as 

 long as forty minutes before and after. 

 Although observers in Africa and Eu- 

 rope will have the best views, anyone 

 in the eastern third of North America 

 and nearly all of South America should 

 also be able to spot evidence of the 

 penumbral shadow shortly after 

 the Moon rises. 



On March 29 a total eclipse of 

 the Sun passes across Africa and 

 Western Asia. Totality begins at 

 sunrise over easternmost Brazil, 

 and the dark umbral shadow of 

 the Moon then spends the next 

 thirty-six minutes sweeping 

 northeast over the Atlantic. It 

 makes landfall again in western 

 Africa [see map at left], continu- 

 ing its northeasterly trajectory 

 over Ghana, Togo, Benin, Nige- 

 ria, central Niger, northern 

 Chad, and central and eastern 

 Libya. Totality is longest — nearly four 

 minutes and seven seconds — along the 

 border between Chad and Libya. After 

 passing over the Mediterranean, the 

 track of the eclipse sweeps through cen- 

 tral Turkey, the northwest corner of 

 Georgia, and across Kazakhstan before 

 leaving the Earth at local sunset in 

 Mongolia. A partial solar eclipse will be 

 visible across the rest of Africa (except 

 the southernmost part), Europe, the 

 Middle East, and Western Asia. 



The vernal equinox takes place 

 P.M. on the 20th. Spring cc ices 

 in the Northern Hemisp i lutumn 

 commences in the ' ui rn. 



Unless othenirise <tcd, all times are given 

 in eastern standard time. 



March 2006 N A I L' R A I HISTORY 



