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The Sky This Week
U.S. Naval Observatory's Weekly Blog
"Now let me see," the Golux said. "If you can touch the clocks and never start them, then you can start the clocks and never touch them. That's logic, as I know and use it...." -- James Thurber, "The 13 Clocks"
by Geoff Chester, USNO Public Affairs
09 March 2021
Orion, the Hyades, Mars, and the Pleiades, imaged 2021 March 7 (UT) from Turner Mountain, Virginia
with a Canon EOS Rebel SL2 DSLR, EF-S 18-55mm f/3.5-5.6 zoom lens @ 18mm f/4, and
an Omegon MiniTrak LX2 manual star tracker
The Moon plays hard-to-get this week as she skirts the southeast horizon before dawn, then returns to the early evening sky by the week’s end. New Moon occurs on the 13th at 5:21 am Eastern Standard Time. If you have a clear view to the southeast, look for Luna with the rising planets Jupiter and Saturn before dawn on the 10th. By the end of the week you can find her waxing crescent low in the southwest as evening twilight fades.
It is once again time to exercise the annual spring ritual of setting our clocks ahead by one hour, “springing forward” to Daylight Time at 2:00 am on the morning of the 14th. Love it or hate it, it’s the law of the land as specified in U.S. Code, Title 15, Chapter 6, Sub-chapter IX – Standard Time, and it has been thus codified (with several amendments) since 1918. The provision for advancing our clocks dates to that year in an effort to help factories extend their most productive day shifts to maximize wartime demands. Although it seemed like a logical idea at the time, Daylight Time proved to be so unpopular that the provision for it in the law was repealed a year later. It remained a matter of state and local jurisdictions to invoke Daylight Time until World War II, when it was permanently reinstated as “War Time” by an act of Congress. From February 9th, 1942 until September 30th, 1945 the nation observed year-round Daylight Time. After the war the decision to advance clocks once again became a local matter, but in 1966 it was re-established in U.S. Code. The rule as it exists today was enacted in 2005. While the U.S. Naval Observatory is charged with providing the nation’s reference time-scale, it is not within our scope to enforce the law on how time is observed. That distinction belongs to the Department of Transportation.
You still have a few more evenings of early sunsets to make observations of the constellation of Orion for the benefit of the Globe at Night project. The Hunter is still prominent in the early evening sky, and you can make your observations under fully dark skies by 8:00 pm. Participation is easy; just follow the steps on the Globe at Night website.
The March sky is one of transition from the bright beacons that illuminated the long nights of winter to the more solitary bright stars of spring. As Orion and the stars of the Great Winter Circle heel over to the west, look toward the northeast for the rising stars of Ursa Major, the Great Bear. The seven brightest stars of this constellation for the familiar asterism of the Big Dipper, and while they don’t have the dazzle of Orion’s stars they do form a pattern that almost every Northern Hemisphere skywatcher knows by heart. In the early evening the Dipper seems to be balanced on its “handle”, but as the night passes it revolves westward over the north celestial pole. If you follow the arc of the stars that form the “handle” you will come to the brightest star in the northern hemisphere sky, Arcturus. Sighting this star has always been a sure sign of spring to me, and its cheery rosy tint reminds me that warmer days and nights are coming. Arcturus beams at us from about 37 light-years away, and it is the closest “red giant” star to the solar system. While it is slightly more massive than our Sun, it has begun to evolve toward its eventual demise as it exhausts the hydrogen fuel in its core, giving us a glimpse of Old Sol’s fate in another 2 billion years.
Our sole evening planet is Mars, which spends the week moving through the stars of Taurus, the Bull in the western sky. The red planet will glide to the north of the bright star Aldebaran as the week progresses, leaving the Pleiades star cluster in his wake. At around 8:30 pm local time you will have a fine view of three red objects in this part of the sky, giving you the chance to examine Betelgeuse in Orion, Aldebaran, and Mars in the same field of view.
Jupiter and Saturn reveal themselves just after the start of morning twilight in the southeastern sky. The two planets swapped positions with each other in a spectacular conjunction late last December, so Saturn now leads Jupiter over the horizon. Both planets will be hard to spot without a good view to the southeast, but they will become more prominent as we move deeper into spring.
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