In the Sky This Month

The planet Mercury will stand close to the Moon during the dawn twilight tomorrow. It looks like a fairly bright star, to the lower right of the Moon. The brighter planets Venus and Jupiter align well to their upper right.

Venus, Jupiter, and the twins of Gemini congregate around the Moon before dawn. Venus, the Morning Star, is close to the lower right of the Moon. Jupiter is farther to the upper right, and Gemini’s twins are to the upper left of the Moon.

The crescent Moon will slide past three bright planets over the next three mornings, growing thinner as it does so. First up is Jupiter, the largest planet in the solar system. It looks like a bright star below the Moon at dawn tomorrow.

The Moon butts up against the star Elnath, the tip of one of the horns of Taurus, early tomorrow. They will appear to almost touch as they climb into good view, about 2:30 or 3 a.m. They will be closest as viewed from the East Coast, especially the northeast.

Sirius, the brightest star in the night sky, is climbing into view in the southeast at dawn. It is the brightest star of Canis Major, the big dog, so it’s known as the Dog Star. In ancient times, its first dawn showing ushered in the Dog Days of summer.

The Moon will be at last quarter tonight as it lines up at a right angle to the Sun in Earth’s sky. After that it will enter the “waning crescent” phase, growing thinner by the day as it loops toward the Sun.

In 1764, Charles Messier was a star-cluster-discovering machine. He found five globular clusters in Ophiuchus. He cataloged them as Messier 9, 10, 12, 14, and 19. They are scattered across the large constellation, and are visible through binoculars.

Barnard 68 is one of the darkest objects in our part of the galaxy. It’s a small cloud that absorbs the light of the stars behind it, so it looks like a “hole” in the Milky Way. It’s in Ophiuchus, the serpent bearer, which is in the southern sky at nightfall.

Ophiuchus passes across the south on summer evenings. The constellation represented the god of medicine. Its stars are faint. Under a dark sky, they form a pattern that resembles a coffee urn. It’s upright in early evening, but on its side later on.

The planet Saturn appears quite close to the Moon tonight. It looks like a bright star to the lower left of the Moon as they climb into good view, by about 11 p.m. A small telescope will reveal Titan, Saturn’s largest, which looks like a tiny star close to the planet.