by Geoff Chester, USNO Public Affairs | 06 August 2024 Sagittarius and Scorpius with the southern summer Milky Way imaged 2022 July 26 with a Canon EOS Rebel SL2 DSLR from Mollusk, Virginia The Moon returns to the evening sky this week, waxing from crescent to First Quarter phase, which will occur on the 12th at 11:15 am Eastern Daylight Time. She courses her way above the southeastern horizon, ending the week just over a degree southwest of the bright star Antares in the constellation of Scorpius. We are entering the time when we see a subtle but noteworthy lunar phenomenon known as a major lunar standstill. This occurs once every 18.6 years when the Moon’s orbit carries her to her most extreme north and south declinations. These extremes are most noticeable around the times of Full Moon near the winter solstice, when Luna’s bright disc reaches her highest transit altitude for observers in the Northern hemisphere. This month the waxing gibbous Moon will reach her most southerly declination on the 15th, when she will be just over five degrees south of the ecliptic. These extreme declinations will continue into 2025. In 9.3 years Luna will each a minor standstill, when she will have a minimum excursion between declinations. The evening sky is a showcase for many of summer’s signature constellations. Looking south at around 10:00 pm you will see the distinctive outline of Scorpius, one of the most ancient of the star patterns in our sky lore. Depictions of the scorpion date back over 5000 years, when we find renderings of it in pre-dynastic Egypt and ancient Babylon. Its resemblance to the arachnid is quite unmistakable, with the bright red-tinted star Antares aptly seen as its heart. West of Antares are a near vertical line of blue hued stars that outline its head. The scorpion’s body curls down to the southern horizon, then curves northeastward, terminating in a close pair of stars that mark the stinger at the end of its tail. Scorpions are not found in the scattered islands of the Pacific Ocean, but the Polynesians noted the southern part of Scorpius with great reverence. In their lore it represented the great fishhook used by their creator god Maui to dredge their island homes up from the bottom of the ocean. Just east of Scorpius is the constellation of Sagittarius, the Archer. This grouping also has origins in ancient Babylon, where it represented a centaur, a creature with the head and torso of a man and the body of a horse. Trying to see this taxes my imagination, but there is a very prominent asterism made up from the brightest stars that makes a fairly believable “Teapot”. This illusion is enhanced when viewed from a dark sky, where the densest star clouds of the Milky Way seem to depict a cloud of steam rising from the teapot’s spout. When we look at this part of the sky, we are gazing toward the center of our home galaxy. The center itself lies some 30,000 light years away, but we can’t actually see it due to the massive clouds of dust, gas, and stars that obscure it from us. Infrared and radio telescopes can penetrate much of this obscuration, though, and reveal a massive black hole at the galactic center. The area between Scorpius and Sagittarius is one of the best areas of the sky to explore with a small telescope. Nineteen of the 110 bright star clusters and nebulae cataloged by the 18th Century French astronomer Charles Messier are located in this relatively small patch of sky. Look for the yellow glow of Saturn in the southeastern sky as midnight approaches. The ringed planet rises at around 9:30 pm, and continues to work his way into the evening sky. He will reach opposition in another month, when he will be visible in the southern reaches of the sky all night. Mars rises shortly before Jupiter in the early morning sky. The red planet is racing eastward among the stars of Taurus, the Bull, and chases down Old Jove by the end of the week. If you get up before dawn on the morning of the 14th, you will find the two planets less than one-third of a degree apart. This will be the closest planetary appulse for the year, well worth the early wake-up call.