Categories: Sky Reports
The sky 40 minutes after sunset on July 15. Venus has an altitude of only 10° It’s not yet dark enough to see Mercury or any but the brightest stars. Look for Mercury next week when it’s higher. The stars of Leo are above Regulus. Graphic created with SkySafariAstronomy.com.
The planet show is quickly drawing to a close as Venus and Mars sink in the west, setting earlier each day. 45 minutes after sunset Venus sits less 10° above the west horizon. It sets an hour later if you have a flat horizon. Directly above Venus are Mars and Regulus. Regulus is the brightest star in Leo, the Lion, and a star only slightly brighter than Mars; the rest of Leo is above. Note the color contrast between the two. On the 10th Mars is a scant 2/3° above Regulus, but Mars’ eastward motion leaves Regulus behind and their separation has grown to 4° on the 16th – still close enough to see them together in binoculars. On the 14th and 15th Regulus is midway between Mars and Venus. Regulus is virtually on the ecliptic so the moon and planets pass near and sometime occult it, as now.
We’ve enjoyed Venus as the brilliant “Evening Star” since last year, but it’s remarkable how fast it will now disappear. It’s moving between the earth and sun, transitioning from the evening to the morning sky, and it leaves us before July ends. Telescopically it’s a very thin crescent that grows thinner by the day. People have reported seeing Venus as a crescent through binoculars, but you need at least 10 power and preferably more, to mount them on a tripod, and to look before sunset, while Venus is still relatively high and above the most turbulent layers of our atmosphere. Give it a try.
Mercury is beginning to make an appearance in the evening sky to liven things up a bit; more on it next week.
Saturn rises at about midnight, depending on where you are in your time zone, and an hour later it’s very low in the east-southeast, in Aquarius. Saturn is brighter than any star in Aquarius and is yellowish, so it’s easy to pick it out from the fainter stars nearby.
Jupiter rises 2½ hours later, and it’s so bright there is no missing it. Jupiter is in Aries, another constellation without bright stars. On the morning of the 11th the moon is 4° from Jupiter.
Astronomical dusk – when the sun’s light is entirely gone and the sky is fully dark – occurs 1 hour 45 minutes after sunset (in July), and then the constellation Scorpius is due south and that’s a great time to look at it. First, it’s one of the small handful of constellations that looks like what it’s named after – a scorpion. Those of us who live or vacation in the desert southwest are familiar with them, as were the Mesopotamians in what is now Iraq when constellations were first named more than 6,000 years ago, and these stars have been seen as a scorpion since then. With your eye the bright orange star Antares stands out – it’s the heart of the scorpion – and with binoculars the large naked-eye star cluster M7 is so conspicuous that it was marveled at in ancient times.
This is the entry for Scorpius in my book “Stargazing for Beginners”, Roxbury Park, 1998:
Scorpius — the Scorpion (SKOR–pee-us)
The Scorpion is a major constellation in the summer sky. It is low on the southern horizon as seen from the United States, and we lose much of its splendor, but far south of the equator, where it passes overhead, it is a magnificent string of bright stars.
Scorpius truly looks like a scorpion, and people have been calling it the Scorpion since prehistoric times — for at least 6,000 years. The bright red star Antares is his heart. His tail is a long string of bright stars that goes down and to the left of Antares, and then curls back up to end in two stars close together that are his stinger. The front part of his body stretches from Antares a short distance to the right, ending in his claws, which are three stars in a north-south row.
Scorpius now has only three stars for stubby claws, but long ago the claws included the stars of Libra, to the right. Then the claws were huge and Scorpius was a frightening creature.
In Greek mythology Scorpius was the enemy of Orion, the Hunter. When Orion boasted that he could kill any living animal, the alarmed earth goddess sent a scorpion to kill him. The scorpion came to symbolize death and darkness; Orion, who was reborn, symbolized life and light. After Orion’s death, both he and the scorpion were placed in the sky but on opposite sides, so one sets while the other rises and the battle between light and dark, life and death, continues eternally.
Scorpius is a member of the zodiac and the sun cuts across its very northernmost part. According to the modern way the sky is divided, the sun is within its boundaries for only one week from approximately November 23 through November 29. The sun then moves through Ophiuchus before continuing on to Sagittarius.
The Milky Way runs through the Scorpion. Like Sagittarius, Scorpius is littered with star clusters that are visible in binoculars or a small telescope. Open clusters abound, and two globular clusters of note are M4, a bright sixth-magnitude cluster only 1-1/3° west of Antares, and seventh-magnitude M80, 4½° to the northwest of Antares.
The Rival of Mars
Hearts are red, and the Scorpion’s heart is a red star. Its name, Antares (ann-TAIR-ees), is Greek for “anti-Mars,” better translated as “rival of Mars” because the star rivals Mars in the redness of its color. Antares is a giant almost 10,000 times as bright as our sun and 500 light-years distant. It is very similar to Betelgeuse in the Scorpion’s enemy, Orion. Antares is one of the four ancient Persian royal stars — bright stars near the path of the sun.
Clusters in the Tail
Two especially large open star clusters, M6 and M7, are bright enough to see without binoculars and were known (although their nature was not) in ancient times. They lie above the Scorpion’s stinger and to the right of the top of the teapot of Sagittarius. M6 is 2,000 and M7 less than 1,000 light-years distant. Use binoculars or a low-power wide-angle telescope.
Stellar Vista Observatory provides portable telescopes and tripod mounted binocular kits on loan for free to residents and visitors in Kane County. Enhance your enjoyment of the night sky! To learn more, request a loan, or attend one of SVO’s free public star parties for 2023, visit https://stellarvistaobservatory.org/ or drop in to the Kane County Office of Tourism.