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The Sky This Week, 2010 June 8 - 15

The Moon Meets Venus, "Solstice Season" Starts
Mars & Regulus Conjunction, 2010 June 7, 02:20 UT
Imaged from Shoestring Observatory, Alexandria, VA
with a Canon PowerShot A95 digital camera,
15s @f/4.0, ISO 100.
Mars & Regulus are at lower right, Saturn at left of field

The Moon returns to grace the early evening sky by the end of the week.  New Moon occurs on the 12th at 7:15 am Eastern Standard Time.  Look for Luna’s slender crescent near bright Venus on the evenings of the 14th and 15th.  

The end of the week brings not only the return of the Moon, but it also begins a two-week “season” of phenomena associated with the summer solstice.  While the solstice itself falls on the morning of the 21st, the earliest sunrise of the year occurs a week before on the 14th.  On this day, and for a few days on either side, Old Sol peeps over the Washington horizon at 5:42 am EDT.  However, the time of sunset is still slipping a little bit later each evening and will continue to do so until several days after the solstice.  Thus the year’s longest day in terms of the interval between sunrise and sunset will be the day of the solstice, when we’ll have the Sun above the horizon for 14 hours and 54 minutes.  For determined skywatchers, this, of course, means that we experience the shortest nights.  The time between the end of evening astronomical twilight and the beginning of morning twilight is just five hours eight minutes, so if you happen to get a good clear moonless night in the next week, make the most of it, since you won’t have much time!  There are plenty of things to look at in the few dark hours, ranging from the setting galaxies of the Virgo Cluster to the rising treasures of the summer Milky Way.

Venus hangs in the northwestern sky during the darkening hours of evening twilight.  You should be able to pick Venus out in the sky almost immediately after sunset, and the bright glow seems to intensify as the surrounding sky darkens.  The dazzling planet forms an almost perfect straight line with Castor and Pollux on the evening of the 12th.  On the 14th a d-day old crescent Moon makes an attractive triangle with Venus and Pollux, and the following night forms a line with the planet and the star.

Mars speeds eastward away from the star Regulus, setting his sights on Saturn some 25 degrees to the east.  Those of you who saw the conjunction between mars and Regulus last week were treated to a very colorful view as the red planet perched just north of the blue star.  By the end of the week Mars will have put some five degrees of distance between himself and the star.

Saturn is barely inching eastward as Mars begins to hurtle toward him.  The ringed planet has been spending the past several weeks been located within two degrees of a third-magnitude star with the wonderful name of Zavijava in the western edge if Virgo.  He will stay close to the star for several more weeks before you notice any appreciable eastward creep.  Saturn’s famous rings are still presented nearly edge-on to our line of sight, but their shadow across the planet’s disc presents a very striking sight in the modest telescope.

Jupiter now rises at around 2:00 am, so he’s well up in the southeast at the start of morning twilight.  Just as amateur astronomers were getting used to the planet’s odd appearance thanks to the disappearance of the South Equatorial Belt, another startling event occurred on June 3rd that has Jupiter observers buzzing.  Two amateurs, one in the Philippines, the other in Australia, simultaneously imaged an object hitting the giant planet’s atmosphere and causing a bright flash.  In the past when such impacts have occurred, a dark ash cloud usually appears at the point of impact.  So far none has been sighted for this event, but it’s now making an even more compelling argument to get up early and give Old Jove the telescopic “once-over”.

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