by Geoff Chester, USNO Public Affairs | 18 June 2024 Scorpius over Desolation Canyon, Utah imaged under moonlight, 2018 June 25 The Moon brightens the overnight hours this week, skirting the southern horizon as she waxes to her full phase, which occurs on the 21st at 9:08: pm Eastern Daylight Time. June’s Full Moon is popularly known as the Strawberry Moon since it is the time of year for peak ripening of these tasty treats. Other names include the Green Corn Moon, Hot Moon, Mead Moon, and Honey Moon. Many of these names reflect the warm tone of Luna’s face due to her extreme southern declination. Her light must pass through more of Earth’s atmosphere to reach northern latitudes, and that denser air scatters more blue light than red. This gives the Moon a slight amber tint, especially if the air is warm and humid. Look for the bright red-tined star Antares just east of the Moon on the evening of the 19th. On the 21st she sits atop the “spout” of the Teapot asterism in Sagittarius. The summer solstice occurs on the 20th at 4:51 pm EDT. At this moment the center of the Sun’s disc stands overhead on the Tropic of Cancer at a point northwest of the Hawai’ian Islands. For a day before and after the solstice the Sun’s apparent north/south motion appears to stop, then gradually begins to creep southward. This is a moment that has been recognized since antiquity. Scattered throughout the Earth we find abundant archaeological evidence of the importance of the solstice to our ancient forebears. From simple spiral patterns pecked with stones on rock faces to the elaborate structures of Stonehenge and major temple complexes like Karnak in Egypt, the tracking of the Sun in its annual circuit of the sky has been a key factor in the development of civilized societies. The ability to read the Sun’s position throughout the year enabled our primitive ancestors to master agriculture and feed whole communities. The solstice brings the year’s shortest nights, which here in Washington last just over 9 hours between sunset and sunrise. If you factor in astronomical twilight, true darkness lasts about six hours. The latest sunsets will occur for several days during the last week of June, and sunset only occurs 10 minutes earlier by late July. However, by August we really begin to notice the earlier onset of evening, much to sky watchers’ delight. Bright stars are about the only objects that are easily visible over the coming moonlit summer evenings. High in the south is the rosy glimmer of Arcturus, which is bright enough to appear about half an hour after sunset. It is the brightest star in the northern hemisphere of the sky and “sets the table” for summer’s other bright luminaries. By 11:00 pm the sky is fully dark, and several other bright stars command our attention. One of my favorites is Antares, the ruddy “heart” of Scorpius, the Scorpion. The star’s red tint tells us that it is a type of star known as a “red giant”, a huge, swollen star that is close to its evolutionary end. It is truly gigantic; if it occupied the Sun’s position in our solar system, the orbit of Mars would fit inside it. A similar star graces the winter sky. Betelgeuse in Orion is another evolved star, but you will never see the two in the sky together. In Greek mythology the Scorpion and the Hunter were mortal enemies, so they were placed opposite each other in the sky. Rising in the east is the asterism known as the Summer Triangle, consisting of the stars Vega, Deneb, and Altair. They will gain prominence in the sky as July and August roll by. On a moonless night from a dark site you will see some of the brightest star clouds in the Milky Way piercing the Triangle’s center. Look for the yellow glow of Saturn in the southeastern sky as morning twilight begins. The ringed planet is slowly coursing his way through the dim constellations of autumn, so you should have no trouble locating him. Look close to the southeast horizon for the pink-hued glimmer of Mars. Both planets will be well-placed during the fall and winter evenings.