Scorpius and Sagittarius highlight July nights, scooting low across the south. Antares highlights the scorpion’s hook-shaped body, with teapot-shaped Sagittarius to its left. Under dark skies, the Milky Way rises from the teapot’s spout like steam. Meanwhile, the Big Dipper stands high in the north and northwest during the evening, with its handle to the upper left and bowl to the lower right.
The full Moon of July is known as the Hay Moon, Thunder Moon, or Apollo Moon.
Perigee July 13
Apogee July 25
Moon phases are Central Time.
Spring arrives in the northern hemisphere tomorrow, when the Sun crosses the celestial equator from south to north, marking the vernal equinox. Over the next three months, the Sun will travel farther northward, bringing longer days north of the equator.
The heart of the galaxy Messier 87 features a monster black hole encircled by swirling hot gas. Powerful magnetic fields fire some of the gas outward as deadly radiation beams. M87 is low in the east by mid-evening, below Denebola, the tail of the lion.
The Virgo Cluster is a group of more than 1,500 galaxies about 55 million light-years away. It is centered near the border between Virgo and Leo, a spot that’s low in the east at nightfall and climbs higher later on. Many of the galaxies are easy targets for small telescopes.
From dark skywatching locations, a faint pyramid of light glows faintly in the west after nightfall the next few evenings. This dim glow is the zodiacal light, which is sunlight reflecting off of tiny grains of dust scattered around the inner solar system.
A three-way tug-of-war is playing out in the constellation Leo, which is in the east at nightfall. Three galaxies there are tugging at one another, producing spectacular results. The galaxies are M65, M66, and NGC 3628, known as the Leo Triplet.
Pyxis, the celestial compass, is quite low in the southeast at nightfall. It is a short streak of faint stars that aims toward the remnants of the Argo, the ship that carried Jason and the Argonauts.
To the eye, the brightest star in the night sky is Sirius, which is in the south at nightfall. If we could see ultraviolet light, however, the brightest star would be Adhara, a little below Sirius. It’s quite hot, so it emits much of its light in the ultraviolet.
Four star clusters follow a narrow path near Canis Major, the big dog: Messier 46, 47, 48, and 50. They are in the south and southeast at nightfall. Look for Sirius, the brightest star in the night sky, due south. The clusters spread to the left and upper left of Sirius.
Winter brings out some prominent constellations. One of the most conspicuous is Canis Major, the big dog. It’s best known for Sirius, the Dog Star, which is the brightest star in the night sky. Sirius is a third of the way up the southern sky at nightfall.
The Moon is at last quarter tonight, three-quarters of the way through its month-long orbit around Earth. At last quarter, sunlight illuminates exactly half of the hemisphere facing our way, so it looks as though someone sliced the Moon in half.
