In the Sky This Month

Mercury stands low in the east-northeast as twilight begins to tint the sky the next few mornings. The little planet looks like a fairly bright star, but it is so low that you need a clear horizon to spot it.

The Moon reaches its first-quarter phase today at 12:31 p.m. CDT. It lines up at a right angle to the Sun, so sunlight will illuminate half of the lunar hemisphere that faces Earth.

Deneb, the brightest star of Cygnus, the swan, stands high in the eastern evening sky at this time of year. It forms the northernmost point of the big, bright Summer Triangle, so it’s easy to pick out.

Spica is the leading light of the constellation Virgo and the 16th-brightest star in the night sky. It dazzles even though it is 250 light-years away. It perches to the lower left of the Moon this evening.

M51, a system that consists of a large, bright galaxy and a smaller, fainter companion, is below the star at the end of the Big Dipper’s handle. It’s easily visible through modest telescopes. The dipper is high in the northwest this evening.

During moonless August mornings, a ghostly pyramid of light sometimes climbs from the eastern horizon. Called the zodiacal light, this pale glow is caused by sunlight reflecting off tiny dust grains in the plane of Earth’s orbit.

Jupiter, the solar system’s largest planet, stands about a third of the way up the southern sky at nightfall. It looks like a brilliant star and is the brightest object in the sky for most of the night.

The Milky Way, which is the subtle glow of the disk of our home galaxy, arcs across the sky on summer nights. It’s anchored in the south by the constellation Sagittarius, which forms the outline of a teapot.

The Moon will be new tonight as it crosses the imaginary line between Earth and Sun. It will be hidden in the Sun’s glare. It will return to view as a thin crescent in the western sky after sunset on Friday.

The black hole at the center of the Milky Way galaxy is above the spout of the teapot formed by the constellation Sagittarius, which is low in the south at nightfall. The black hole is hidden behind thick clouds of dust, so it’s blocked from view.