March 2011 Celestial Calendar & Observing Notes c/o Dave Mitsky

[Big Dipper]

March 2011 Celestial Calendar & Observing Notes courtesy of Dave Mitsky (calendar data also reproduced in our forum calendar).

All times, unless otherwise noted, are UT.

3/1 Venus is 1.6 degrees south of the Moon at 4:00

3/4 New Moon (lunation 1091) occurs at 20:46

3/6 Uranus passes 0.8 degree south of the point of the vernal equinox today; the Moon is at apogee, subtending 29 arc minutes from a distance of 406,583 kilometers (252,639 miles), at 6:49

3/7 Jupiter is 7 degrees south of the Moon at 5:00

3/9 Mars is at perihelion today

3/11 Mercury is at the ascending node today; the Moon is 1.7 degrees south of the bright open cluster M45 (the Pleiades) in Taurus at 5:00

3/12 The Lunar X (also known as the Purbach or Werner Cross), an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to occur at 5:24; asteroid 3 Juno (magnitude 8.8) is at opposition at 10:00; First Quarter Moon occurs at 23:45

3/13 Daylight Saving Time (DST) begins today; the Moon is 1.2 degrees south of the bright open cluster M35 in Gemini at 19:00

3/14 Asteroid 20 Massalia (magnitude 8.8) is at opposition at 23:00

3/15 Venus is at the descending node today

3/16 Mercury is at perihelion today; Mercury (magnitude -1.0) is 2 degrees north of Jupiter (magnitude -2.1) at 17:00

3/17 Jupiter is at perihelion today

3/19 Full Moon (known as the Crow, Lenten, and Sap Moon), the largest of 2011, occurs at 18:10; the Moon is at perigee, subtending 33 arc minutes from a distance of 356,575 kilometers (221,565 miles), at 19:09

3/20 The vernal equinox occurs at 23:21

3/21 Saturn is 8 degrees north of the Moon at 0:00; Uranus is in conjunction with the Sun at 12:00

3/23 Mercury is at its greatest eastern elongation (19 degrees) at 1:00

3/26 Last Quarter Moon occurs at 12:07

3/27 Mercury is at its greatest heliocentric latitude north today; Venus is 0.1 degrees south of Neptune at 0:00

3/28 The Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur at 6:07; asteroid 4 Vesta is 1.2 degrees south of the Moon, with an occultation taking place in Iceland, at 7:00

3/30 Mercury is stationary at 17:00

3/31 Neptune is 5 degrees south of the Moon at 2:00; Venus is 6 degrees south of the Moon at 13:00

John Herschel (1792-1871), Percival Lowell (1855-1916), Albert Einstein (1879-1955), and Walter Baade (1893-1960) were born this month.

After evening twilight, the zodiacal light is visible in the west from a dark site during early March.

The Moon is located in Sagittarius and is 25.7 days old at 0:00 UT on March 1. It's at its greatest northern declination of +23.8 degrees on March 12 and its greatest southern declination of -23.7 degrees on March 25. Latitudinal libration is at a maximum of +6.5 degrees on March 19 and a minimum of -6.6 degrees on March 6. Longitudinal libration is at a maximum of +7.6 degrees on March 25 and a minimum of -8.0 degrees on March 13. Large tides occur on March 19 through March 22. The first photograph of the Moon was taken on March 23, 1840. Visit Extreme Lunar Crescent Data [L1091-1104] | Saber Does The Stars for tips on spotting extreme crescent Moons. Times and dates for the lunar light rays predicted to occur this month are available at Lunar Sunrise/Sunset Crater Rays

The Sun is in Aquarius on March 1 at 0:00 UT. It crosses the celestial equator at 7:21 p.m. EDT on March 20, bringing spring to the northern hemisphere.

Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on March 1: Mercury (magnitude -1.7, 5.0", 99% illuminated, 1.35 a.u., Aquarius), Venus (magnitude -4.1, 15.8", 71% illuminated, 1.05 a.u., Sagittarius), Mars (magnitude 1.1, 4.0", 100% illuminated, 2.37 a.u., Aquarius), Jupiter (magnitude -2.1, 34.0", 100% illuminated, 5.80 a.u., Cetus), Saturn (magnitude 0.5, 18.9", 100% illuminated, 8.79 a.u., Virgo), Uranus (magnitude 5.9, 3.3", 100% illuminated, 21.02 a.u., Pisces), Neptune (magnitude 8.0, 2.2", 100% illuminated, 30.98 a.u., Aquarius), and Pluto (magnitude 14.1, 0.1", 100% illuminated, 32.42 a.u., Sagittarius).

Visibility of the classical planets at midmonth from 40 degrees north latitude: Mercury is visible during evening twilight; Venus rises at 6:00 a.m. EDT; Jupiter sets at 8:00 p.m. EDT; Saturn rises at 9:00 p.m. EDT and transits at 3:00 a.m. EDT.

Mercury and Jupiter can be seen in the west in the evening. Saturn is located in the southeast at midnight. Venus is in the southeast, Saturn is in the southwest, and Neptune is in the east in the morning sky.

Mercury, Mars, and Neptune are all located in Aquarius as March begins. Mars, Mercury, and Jupiter all reach perihelion this month.

Mercury travels from Aquarius to Pisces during March. The fact that it’s at greatest eastern elongation on March 23, combined with a favorable angle of the ecliptic, means that this will be Mercury’s best evening apparition of the year for observers at mid-northern latitudes. Mercury has decreased in brightness to magnitude -0.5 but increased in width to 7.5 arc seconds by that date.

This month Venus exits Sagittarius, crosses through Capricornus, and enters Aquarius. On March 27 at 1:00 UT, Venus passes just 9 arc minutes south of the 60,000-times-fainter planet Neptune, an event visible from central Asia. During March, Venus diminishes in magnitude from -4.1 to -3.9, declines in angular size from 16 to 13 arc seconds, and increases in illumination from 71 to 80%. By the end of March, Venus rises only 75 minute before the Sun.

Mars is not visible this month.

Jupiter is two degrees south of Mercury on March 16, at which time Jupiter will subtend 33 arc seconds and Mercury just 6.2 arc seconds. The gas giant reaches perihelion on March 17. This will be Jupiter’s closest approach to the Sun in over 50 years. Jupiter is lost in the glare of the Sun by month’s end. Data on the Galilean satellites is available at SkyandTelescope.com - Interactive Observing Tools - Jupiter's Moons Javascript Utility

In the latter part of March, Saturn attains its maximum brightness (magnitude 0.4) and apparent size (19.3") for the year. The ring tilt angle is nine degrees. Saturn retrogrades through Virgo this month. It’s just eight arc minutes southwest of the sixth-magnitude star 46 Virginis on the evening of March 13 and four degrees southeast of the third-magnitude binary star Porrima (Gamma Virginis) by the end of March. Saturn’s major satellite Titan was discovered on March 25, 1655 by the Dutch astronomer Christiann Huygens. Eight-magnitude Titan is due north of Saturn on the nights of March 8 and March 24 and due south of the planet on the night of March 16. Tenth-magnitude Dione and Tethys come within three arc seconds of one another to the east of Saturn on the evening of March 18. On March 12, twelfth-magnitude Enceladus is only three arc seconds south of Tethys between 10:00 and 11:00 p.m. EST. Iapetus shines at eleventh-magnitude as it passes two arc minutes from Saturn on the nights of March 3 and March 4. On March 24, when it’s at greatest western elongation, Iapetus glows at tenth-magnitude ten arc minutes from Saturn. For further information on Saturn’s satellites, browse SkyandTelescope.com - Interactive Observing Tools - Saturn's Moons Javascript Utility

Uranus is in conjunction with the Sun on March 21 and consequently is not visible this month. Sir William Herschel discovered Uranus on March 13, 1781. The rings of Uranus were discovered on March 10, 1977.

Neptune appears again low in the morning sky but is more easily seen by observers in the southern hemisphere.

Pluto is not readily observable this month.

During March, asteroids 3 Juno and 20 Massalia both shine at ninth magnitude as they pass northwestward from western Virgo into southeastern Leo. The two asteroids are separated by about three degrees over the course of the month. Juno is half a degree south of the fourth-magnitude star Sigma Leonis on the nights of March 22 and March 23. Massalia glides just a tenth of a degree south of the fifth-magnitude star Tau Leonis on the night of March 23. The twelfth-magnitude asteroid 72 Feronia occults the eight-magnitude star SAO 138141 in Leo in the early morning of March 9 and the twelfth-magnitude asteroid 224 Oceana occults the eighth-magnitude star SAO 138776 in Virgo on the morning of March 20 for North American observers. Click on Monthly Index of Asteroid Occultation Path Predictions for additional information on these events.

There’s a dearth of noteworthy comets this month.

A free star map for March can be downloaded at Skymaps.com - Publication Quality Sky Maps & Star Charts