You are here: Home USNO News, Tours & Events Sky This Week The Sky This Week, 2019 March 5 - 12

The Sky This Week, 2019 March 5 - 12

Springing ahead...reluctantly?
1918 poster celebrating passabe of the Standard Time Act
1918 poster celebrating passage of the Standard Time Act
Courtesy of the Library of Congress

The Moon returns to the evening sky this week, emerging from the evening twilight glare as she climbs northward along the ecliptic.  If you have clear skies and a flat western horizon try to spot Luna’s 32-hour old crescent on the evening of the 7th.  Over the course of the week she will move through the autumnal stars, passing southeast of ruddy Mars on the evening of the 11th.  She ends the week to the west of the bright star Aldebaran.  First Quarter occurs on the 14th at 6:27 am Eastern Daylight Time.

Yes, you read that correctly.  This is the week when we advance our clocks by one hour and begin observing Daylight Time in most of the United States.  Technically this occurs at 2:00 am local time on Sunday morning, March 10th, and Daylight Time will remain in force until 2:00 am local time on November 3rd.  This annual ritual dates back over 100 years and was first implemented in Germany and England during the First World War.  It was adopted in 1918 in the United States by an Act of Congress on March 19th, which also codified the observance of standard time and time zones.  The idea was pushed by a number of interests and ultimately passed on the premise that the “extra” time in the evenings afforded more time for people to work in their “victory gardens”.  It was hugely unpopular, and the Daylight Time provision in the law was repealed in 1919.  Apart from the “War Time” interval during World War II Daylight Time was more or less left up to state and local authorities.  Federal regulation wasn’t re-instated until 1966 with the passage of the Uniform Time Act.  Since that time there have been various changes in the duration of Daylight Time, and the rules that we observe today resulted from legislation passed in 2005.  The matter has never been particularly popular, and today a number of states are considering breaking with Uncle Sam and establishing their own rules.

As evening twilight fades into the dark of night the sky is still dominated by Orion and the bright stars of the Great Winter Circle.  You’ll find nine of the 25 brightest stars in the sky in this region with Orion as the centerpiece constellation.  This is an area of the sky that I love looking at with my binoculars.  Even from the heart of the city the stars of the Winter Circle show off their subtle colors, ranging from the ruddy tint of Betelgeuse in Orion to the blue dazzle of Sirius to the east of the Hunter and the golden glimmer of Capella, close to the zenith as evening twilight deepens.  As the evening progresses, these stars swing to the west, and the sky becomes notably devoid of bright stars.  One exception can be found rising in the east by 10:00 pm.  Here you’ll find a rose-tinted star that outshines all other stars in the northern celestial hemisphere.  This is Arcturus, the closest “red giant” star to the Sun.  It is located just under 37 light-years from us and exhibits rapid motion across the sky.  This “proper motion” was first described in 1718 by Edmund Halley, who noted that Arcturus, Sirius, and Alpha Centauri were over half a degree away from the positions described by the ancient Greek astronomer Hipparchus.  In 1933 light from Arcturus was focused on a photo-tube that triggered a mechanism that cut a ribbon to open the World’s Fair in Chicago.  The star was chosen because at the time its distance was thought to be 40 light-years, and that time-span had elapsed since the closing of the World Columbian Exposition in 1893 which also took place in Chicago.

You might still be able to spot fleet Mercury in the glow of evening twilight early in the week.  If you can locate the thin crescent Moon on the evening of the 7th, use binoculars to locate Mercury about 8 degrees to the right of the Moon. 

Mars gets a visit from Luna on the evening of the 11th as he continues his course eastward through the dim stars of Aires.  He will make steady progress eastward toward the brighter stars of Taurus, the Bull, and by the end of the month he will be close to the famous Pleiades star cluster. 

Jupiter may be found in the early morning sky between the constellations of Scorpius and Sagittarius.  These signs of summer will keep Old Jove company throughout the rest of the year.  Unfortunately for those of us in northern temperate latitudes this means that Jupiter will never get very high above the southern horizon, so getting a good telescopic view of him will be problematic.

Saturn rises just under two hours after Jupiter and holds court just east of Sagittarius.  Like Jupiter he is far to the south on the ecliptic plane, so getting a clear view of him requires a good horizon and exceptionally steady air.

Venus rises shortly before the beginning of morning twilight.  Look for the dazzling planet low in the southeastern sky as the horizon brightens.  You should be able to spot her right up to the moment of sunrise.

USNO Master Clock Time
Javascript must be Enabled