In The Sky This Month – March 2011

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of March 2011.

March 2011 Highlights
* Mercury and Jupiter dazzle after evening twilight
* Saturn is up all night
* Venus slowly loses altitude before dawn

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <>.


Moon – The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Mar 1 - Moon 1.6° from Venus
Mar 4 - New Moon
Mar 6 - Moon 6° from Jupiter
Mar 11 - Moon 2° from Pleiades
Mar 12 - First Quarter Moon
Mar 12 - Moon 7° from bright star Aldebaran
Mar 15 - Moon 9° from bright star Pollux
Mar 16 - Moon 5° from Beehive Cluster
Mar 17 - Moon 5° from bright star Regulus
Mar 19 - Full Moon
Mar 20 - Moon 7.5° from Saturn
Mar 21 - Moon 2.5° from bright star Spica
Mar 24 - Moon 3° from bright star Antares
Mar 26 - Third Quarter Moon
Mar 28 - Moon 1.5° from asteroid Vesta
Mar 31 - Moon 5.5° from Venus

Mercury and Jupiter – The innermost planet has its best evening apparition of the year this month (for observers in the northern hemisphere). From mid-month till the end of the month, Mercury will be observable low in the western sky a half-hour or so after sunset. As an added bonus, Jupiter will be located nearby. The two will be closest on Mar 15 when they will only be 2° from each other. By the end of the month both planets will be located too close to the Sun to be easily seen.

Mar 6 - Moon 6° from Jupiter
Mar 15 - Mercury and Jupiter within 2° of each other
Mar 23 - Mercury at Greatest Elongation East

Saturn – Saturn starts the month rising a few hours after sunset. By the end of the month it is only a few days from opposition (on April 3) and rises just moments after sunset. Located in Virgo, the ringed planet is a close match in brightness (mag +0.4) to Spica, the brightest star in Virgo (mag +1.0). Saturn spends the entire month within 10° of Spica.

Mar 20 - Moon 7.5° from Saturn

Venus –  On Mar 1, Venus rises almost 2 hours before the Sun in the eastern sky though this drops to just a little over an hour by the end of the month.

Mar 1 - Moon 1.6° from Venus
Mar 31 - Moon 5.5° from Venus

Mars – Too close to the Sun for observation.


Meteor activity is near a seasonal minimum in March. The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During March mornings, 10-12 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

None this month…

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2011 Meteor Shower Calendar.


Naked Eye Comets (V < 6.0)

None this month…

Binocular Comets (V = 6.0 – 8.0)

None this month…

Small Telescope Comets (V = 8.0 – 10.0)

None this month…


Binocular and Small Telescope Asteroids (V < 8.0)

(4) Vesta

Vesta is the brightest asteroid in the Main Belt. This is due to its high albedo (or reflectivity) which causes it to reflect ~42% of the light that strikes it. Vesta is also peculiar in that it appears to have evidence of volcanism on its surface. Similar to the Moon, Vesta may be covered with large expanses of frozen lava flows. It is classified as a V-type asteroid and is the only large asteroid with this classification. Many of the smaller V-type asteroids are chips of Vesta blasted off it by past asteroid and comet impacts. Vesta has dimensions of 347x336x275 miles or 578×560×458 km.

The maps below were created from images taken with the Hubble Space Telescope. The geography is dominated by a large impact crater located near the south pole (the blue ‘donut’ in the elevation map). Perhaps this crater is the result of the impact that blasted off the smaller V-type asteroids. We’ll know more this summer when NASA’s Dawn spacecraft enters orbit around Vesta for a full year. Currently the encounter is scheduled for July 2011 to July 2012.

Images and models of the shape of asteroid (4) Vesta. In the upper left is a real HST image, to the upper right is a model of Vesta’s shape, and on the bottom is an elevation map . Credit: NASA/STScI.

Vesta spends the month around magnitude 7.7 as it moves eastwards through eastern Sagittarius.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Vesta from Heavens Above.