In the Sky This Month

Although July offers warm, dry conditions for skywatching, it also provides some of the shortest nights of the year in the northern hemisphere, limiting the hours under the stars. Fortunately, some of the best skywatching sights are visible in the early evening, not long after sunset. Venus reigns as the Evening Star all month, slowly climbing the western sky. Mercury peeks into view below Venus for much of the month, with the star Regulus close to both of them.

July 16: Delphinus

Delphinus, the dolphin, is in good view in the east at nightfall. This tiny pattern of stars really does look like a dolphin. Look for it swimming into view in the east as darkness falls, and climbing high across the south during the night.

July 17: Cassiopeia

Cassiopeia the queen sits low in the north-northeast at nightfall, then wheels high to the north at first light. Its stars form a bright letter W, so it’s one of the easiest constellations to pick out.

July 18: Lupus

Skywatchers at far-southern latitudes can see Lupus, the wolf, leaping low across the sky on summer evenings. You need dark skies and a clear horizon to find him. The wolf is below the more prominent constellation Scorpius.

July 19: Moon and Companions

Spica is the bright star to the lower right of the Moon tonight. Although it looks like a single star, it is at least two stars. One of them is more than 11 times the mass of the Sun, while the other is about seven times the Sun’s mass.

July 20: Moon and Jupiter

Jupiter, the largest planet in the solar system, stands just below the Moon this evening and looks like a brilliant star. Binoculars reveal Jupiter’s biggest moons, which look like tiny stars near the planet.

July 21: Two Crosses

The Northern Cross is another name for Cygnus, the swan, which sails high overhead on summer evenings. When we look at Cygnus, we’re looking down the spiral arm that contains our own solar system, so we see many amazing celestial objects.

July 22: Vega

Vega, the fifth-brightest star in the night sky, is enthroned at the top of the sky tonight. The name Vega is from an ancient Arabic name that means “swooping eagle.” Vega is in the constellation Lyra, the harp.