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Searching for a Scorpion

by Geoff Chester, USNO Public Affairs | 20 June 2023

by Geoff Chester, USNO Public Affairs | 20 June 2023

Scorpius (right side of image) and the summer Milky Way, imaged 2022 July 26 from Mollusk, Virginia
with a Canon EOS Rebel SL2 DSLR and an Omegon LX2 mechanical star tracker.
Jupiter and Saturn are the bright objects to the east of the Milky Way.

The Moon returns to the evening sky this week, passing through the departing spring constellations.  First Quarter occurs on the 26th at 3:50 am Eastern Daylight Time.  Look for Luna just three degrees north of Venus on the evening of the 21st.  She forms an elongated triangle with Mars and the bright star Regulus on the evening of the 22nd.  The Moon dives southward along the ecliptic during the week, winding up just over 2 degrees northeast of the bright star Spica on the 27th.

The Northern Hemisphere summer solstice occurs on the 21st at 10:58 am EDT.  This is the moment when the center of the Sun’s disc reaches an ecliptic longitude of 90 degrees.  It is also the time when the Sun reaches its highest declination north of the celestial equator.  For those of us in temperate northern latitudes the solstice marks our longest days and shortest nights.  Here in Washington there will be 14 hours, 54 minutes between sunrise and sunset.  However, the times of sunset haven’t quite reached their latest for the year.  That event will occur on June 28th, when sunset in DC will occur at 8:38 pm EDT.  We experienced our earliest sunrise back on June 14th, but it probably won’t be until late July that the days will really appear to start getting shorter. 

The Moon is the attention-getter during the early evening hours this week.  Luna’s gradually fattening crescent offers a number of interesting features for owners of small telescopes.  I never tire of perusing her battered surface as the terminator slowly creeps across her disc.  During the first few evenings of the week, try to spot the ghostly light of Earthshine on the part of her disc that’s not in direct sunlight.  If the sky is clear and free of haze, Earthshine should be easy to see with the unaided eye.  As the crescent waxes, the phenomenon becomes harder to see, but through binoculars or a telescope you should be able to see it until the first quarter phase.
With our latest sunsets occurring this week into next, we have to wait until after 10:30 pm to see the end of astronomical twilight.  By this time, the bright star Arcturus, the stars of the “Big Dipper”, and the other spring constellations are west of the meridian while summer’s stars are climbing in the east.  The bright stars of the Summer Triangle asterism are steadily climbing in the east to watch over us during the short hours of darkness.  If you look to the south at around 11:30 pm, one of the signature constellations of summer is crossing the meridian.  Look for a red-tinted star about 25 degrees above the horizon.  This is Antares, the “heart” of Scorpius, the Scorpion.  The star’s name translates as “Rival of Mars”, and it is pretty easy to see that its hue gives the red planet a run for his money.  Scorpius is one of the few constellations that bears some semblance to its namesake, and it doesn’t take a huge leap of imagination to trace a stick-figure of the stinging arachnid.  To the west of Antares are three blue-tinted second-magnitude stars that mark the Scorpion’s head.  Follow a curved line of stars down to the southern horizon to trace out the beast’s body, then follow a curved arc of stars to the northeast where you will find a pair of closely-spaced stars that denote the stinger.

In mythology Scorpius was sent by the Earth goddess Gaia to punish Orion, the brash hunter who threatened to kill all of the animals on the planet.  The scorpion crept up on the unsuspecting Orion and stung him with a fatal dose of poison.  Fortunately for the Hunter, he was revived by the healer Ophiuchus, who occupies much of the space above Scorpius in the sky.  Both Orion and Scorpius have bright ruddy stars among their retinue, but you will never see them together in the sky.  Zeus saw to it that the two adversaries would be placed opposite each other in the heavens.

Venus continues to close the gap with Mars.  Over the past few weeks she has charged along the ecliptic in her pursuit of the red planet, but her pace is rapidly slowing.  This week she trims another degree from the gap between the two planets, but she won’t get much closer before she starts a precipitous drop toward the Sun by late July.

Mars plods along on his eastward trek, moving toward Regulus, the brightest star in Leo, the Lion.  He will remain visible in the western sky for a few more weeks before gradually getting lost in evening twilight. 

Saturn is on the threshold of entering the evening sky.  By the night of the 27th he rises just before midnight, but he won’t be an attraction in the evening sky until late July.  You can find him near the meridian as morning twilight begins to brighten the sky.

Jupiter rises at around 2:30 am.  The giant planet is located among the rising stars of Aires, the Ram.  He should be easy to spot during the pre-dawn hours, 20 degrees above the eastern horizon at 4:30 am.


Commander, Naval Meteorology and Oceanography Command | 1100 Balch Blvd. | Stennis Space Center, Mississippi 39529

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