In the Sky This Month

The Moon will stand almost due south at first light tomorrow. The bright planet Saturn will be close to its lower left, with the brighter planet Mars a good bit farther along the same line.

Centaurus, the centaur, hugs the southern horizon this month, and stands due south in late evening. The brightest star of Centaurus that is visible from the United States is Theta Centauri.

In Britain, today is known as May Day. In ancient times, it marked the beginning of summer, not the middle of spring. It is one of the year’s four cross-quarter days, which come roughly half way between a solstice and an equinox.

Orion, one of the most beautiful constellations, is putting in its final evening appearance of the season over the next few nights. It soon will disappear in the Sun’s glare. The next time we see it, it will be in the morning sky shortly before sunrise.

The mighty planet Jupiter looks like a brilliant star. And tonight, it has a close companion: the full Moon. Jupiter is to the lower left of the Moon at nightfall, and follows the Moon across the sky later on.

Two bright lights are passing close to each other in the western evening sky. The brighter light is Venus, the brilliant “evening star.” The other one, to the left or upper left of Venus tonight, is Aldebaran, the eye of Taurus, the bull.

Two big stars with different futures stand below the Moon at nightfall. Their light blurs together into one point: Spica, the brightest star of Virgo. One of the stars will explode as a supernova, while the other faces a fate similar to the Sun’s.

Look well up in the east as darkness falls for yellow-orange Arcturus, the brightest star in the evening sky at this time of year. Well to its lower left is Corona Borealis, the northern crown, a semicircle of stars that opens to the upper left.

Corvus, the crow, is low in the southeast at nightfall and arcs across the southern sky during the night. Corvus’s brightest stars form a small but distinct box. In mythology, the crow was a servant of the god Apollo.

Regulus, the heart of Leo, the lion, stands close to the right of the Moon as darkness falls. The Moon passes the star roughly once per month. Their conjunctions are possible because both lie near the ecliptic, which is the Sun’s path across the sky.