Go Stargazing! March Edition

Venus leaves the evening sky in dramatic fashion this month.  Look west-southwest right as night falls for the brightest thing there except for the Moon.  Keep watching each clear night this month; you’ll see Venus noticeably lower to the horizon each passing day.  By March 20, Venus sets as twilight ends, and by the end of the month, it is gone.  When is the last day the month you can see it?  Venus, on its faster, inner orbit, has come around to our side of the Sun and will pass us on March 27.  Astronomers call this alignment inferior conjunction

(: Smiley Face Over Perth
Creative Commons License photo credit: rich115

In addition, Venus’ orbit is highly inclined to ours.  (The planets orbit almost, but not exactly, in the same plane.)  As a result, we often see Venus pass above or below the Sun at inferior conjunction rather that truly aligning with the Sun.  This time, Venus passes ‘above’ the Sun in our sky, giving us the chance to see it as both evening and morning star!  Do you have a clear horizon, without tall trees or buildings, to the east and west?  If so, then you can try observing Venus very low in the west at sunset and very low in the east the next morning.  It’s best to try this between March 24 and 27. 

Saturn is now up all night.  On March 8, Earth passes between the Sun and Saturn, putting the Sun and Saturn on opposite sides of the Earth.  In this alignment, called opposition, a planet rises at sundown and sets at sunup; it is visible literally all night long.  Saturn is nowhere near as bright as Venus, but it is in a relatively dim star field and therefore is just as easy to see.  Face east at dusk, south at midnight, or west at dawn to see it. 

Mars and Jupiter emerge from the Sun’s glare this month.  Jupiter, in the southeast at dawn, is the brightest thing in that part of the sky unless the Moon is nearby (as it is on March 22, 23, and 24).  Mars moves faster than Jupiter and therefore seems to ‘keep pace’ with the Sun’s apparent motion.  As a result, Mars remains close to the horizon at dawn much of the spring, and takes longer to fully emerge into the morning sky. 

M42 Orion
Creative Commons License photo credit: makelessnoise

Dazzling Orion is due south at dusk.  His belt points up to Aldebaran, the eye of Taurus, the Bull.  The Dog Stars Sirius and Procyon are below Orion in the east.  Sirius is the brightest star we ever see at night.  Look for a fairly bright star just to the right of Sirius and then drop your gaze straight down to the horizon. The bright star just above the horizon, possibly shining through trees, is Canopus, the second brightest star we see at night.  This star is so far south that it never rises for people north of 37 degrees north latitude (Houston is at just under 30 degrees north).  To Orion’s upper left are two stars of similar brightness less than five degrees apart.  These are Castor and Pollux, marking the heads of Gemini, the Twins.  Look in the east at dusk for stars in the shape of a backwards question mark, with a right triangle below that.  These stars are in Leo, the Lion.  Saturn rises in Leo.

Moon Phases in March 2009:

1st Quarter           March 4, 1:45 am
Full                       March 10, 9:37 pm
Last Quarter          March 18, 12:49 pm
New                      March 26, 11:07 pm

Time For... ?
Creative Commons License photo credit: bogenfreund

Sunday, March 8, is the second Sunday of March.  Therefore, we spring forward to Daylight Saving Time at 2 a.m. that morning.  (Clocks officially go from 1:59 a.m. to 3 a.m.)  Don’t forget to set your clocks one hour ahead Saturday night, March 7!

At 6:45 am on Friday, March 20, the Sun is directly overhead at the equator.  This is therefore the vernal (spring) equinox.  On this date, everyone has the same amount of daylight.  For us, day is now longer than night, and days will continue to lengthen until June.  In the Southern Hemisphere, it’s night that is getting longer.  For them, this is the autumnal equinox—the start of fall. 

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