You are here: Home / USNO / News, Tours & Events / Sky This Week / The Sky This Week, 2010 March 9 - 16
The USNO websites,,,,,, and are undergoing modernization efforts. The expected completion of the work and the estimated return of service is Fall 2020, subject to change due to potential impacts of COVID-19.

The Sky This Week, 2010 March 9 - 16

Try a Messier Marathon, count stars for science, or just enjoy the view
Mars, 2010 March 8, 01:19 UT
Imaged with the U.S. Naval Observatory's 1895-vintage
12-inch Clark/Saegmüller refractor telescope

The Moon wanes through her late crescent phases as she wends her way in the pre-dawn sky through the rising constellations of autumn.  New Moon occurs on the 15th at 5:01 pm Eastern Daylight Time.  Luna spends the week virtually by herself in the star-poor reaches of the constellation Capricornus.  She won’t pass any bright objects until her return to the evening sky next week.


A sure sign of approaching spring is the annual change from Standard to Daylight Time.  This year we “spring forward” one hour at 2:00 am on the morning of the 14th.  We are now in the fourth year of setting our clocks ahead on the second Sunday in March, and they will stay on Daylight Time until November 7th.  This raises an interesting conundrum: since we now stay on Daylight Time longer than we do on Standard Time each year, should Daylight Time become the new “Standard”?


The absence of the Moon offers skywatchers a chance to explore the sky well beyond the limits of the solar system.  This is the time of year when amateur astronomers get ready for the observer’s equivalent of the Olympics with an event known as the “Messier Marathon”.  The idea is to see how many of the star clusters, galaxies, and nebulae in the 110-object catalog compiled by French astronomer Charles Messier one can observe in one night.  From our latitude it is theoretically possible to accomplish this feat only around mid-March, so avid amateurs will be flocking to dark-sky locations to try their luck.  This also happens to be the second week in the annual “Globe at Night” observing campaign.  If chasing down “faint fuzzies” for the Messier Marathon seems a bit daunting, this program may be just the ticket.  The idea is to count the number of stars you can see within the bounds of the constellation Orion and report your results to the Globe at Night website.  This simple observing experiment will help astronomers map the distribution of sources of light pollution and will help you become better acquainted with the sky’s most recognized asterism.


The early evening now offers a bright visitor to grace the twilight hour.  Dazzling Venus is now easily seen in the west shortly after sunset, and her brilliant white glow stands in stark contrast to the fading red light of sunset.  Each night finds her a little higher above the horizon, and she will continue to beam down from the west until well into the fall.


Mars reaches the second stationary point in this year’s opposition on the 11th, when his westward motion ceases and he gradually starts to retreat from the vicinity of Castor and Pollux, the Gemini twins.  Even though his apparent disc is now shrinking from night to night it is still possible to glimpse details of his rusty surface through the telescope, especially on nights when the atmosphere is steady.  I’ve had some of my best views of the red planet over the past couple of weeks, well after the time of opposition.


Saturn is fast approaching his own opposition on the 21st.  Now that the last of the snow has melted from my yard and the ringed planet is clear of the neighbor’s oak tree I’ve had my first good glimpse of him for the upcoming apparition.  His famous rings are still tipped close to our line of sight, but he’s easily recognized thanks to these appendages.  Passers-by have no trouble identifying Saturn when they peer through the telescope, and their delight at seeing the planet “live” makes the task of setting up the scope each evening a pleasant one.  If you have a telescope, it’s a great way to get to know the neighbors!