In early March 2014, as seen from the Coachella Valley, the three brightest “stars” visible at dusk all reach their highest points within a span of 21 minutes. In order of brilliance, they are Jupiter, passing within 11 degrees south of overhead; Sirius, the “Dog Star,” 40 degrees up in the south; and Canopus, “Great Star of the (far) South,” less than 4 degrees up when passing due south, about 21 minutes before Sirius does.
Canopus passes directly overhead for observers near latitude 53 degrees south—in other words, southern Argentina or Chile. But here in the Coachella Valley, you must choose your spot carefully, or the mountains might block your view.
From the western Coachella Valley, Canopus passes due south only 4 degrees up in a dark sky at 7:31 p.m. on March 1, and then four minutes earlier each day, to 7:03 p.m. on March 8, and then 7:59 p.m. on March 9—an hour later than you might expect because of our annual shift to daylight saving time. By March 12, the star reaches its high point only an hour after sunset. After a few more days, as the star’s “transit time” keeps backing up toward sunset, the sky will be too bright to catch it at its high point.
Other features of the early evening: A telescope shows up to four of Jupiter’s moons, discovered by Galileo in 1610. Jupiter, red Betelgeuse, and blue Rigel now lie in a nearly straight line pointing downward. Orion’s three-star belt (not shown on the chart) lies midway between those two stars and points the way leftward toward Sirius, and the opposite way toward Aldebaran, eye of Taurus, the Bull, and beyond to the beautiful Pleiades, or “Seven Sisters” star cluster (not shown). The huge Winter Hexagon, in counterclockwise order Sirius-Rigel-Aldebaran-Capella-Pollux-Castor-Procyon and back to Sirius, with Jupiter and Betelgeuse within, contains 8 of the 21 stellar objects of first magnitude or brighter (16 stars and five planets) ever visible from the Coachella Valley. Their constellations include a bull backing away from a charging hunter and his two canine followers, a pair of twins and a chariot driver with mother goat and three kids tucked under one arm.
Following this menagerie is Leo, the Lion, with the bright star Regulus marking his heart. The lion is chasing his dinner across the sky. Quite a menu!
By March’s end, Arcturus, the “Bear Guardian” star, pops up above the east-northeast horizon before mid-twilight. Follow the curve of the bear’s tail (the handle of the Big Dipper) to brilliant reddish Mars, about to rise just south of east, and to Spica, Virgo’s sheaf of grain, 5 degrees to Mars’ lower right within 16 minutes later. (On March 20, the first day of spring, Mars and Spica rise simultaneously in a dark sky about 1.8 hours after sunset. Before March 20, Spica rises first.)
The waxing moon can be spotted daily at mid-twilight in the first half of March. It first appears as an extremely thin crescent on Saturday, March 1. (Please see the separate article about old and young Moons of Feb. 28 and March 1, posted online.) From places with a good, low view near the Coachella Valley, while using binoculars, you might first spot the moon between 6:03 and 6:08 p.m., when the hairline crescent will be 4 degrees south of west and just 5 to 4 degrees above the horizon. The moon will be just more than 18 hours old after new moon, which occurs at 12 a.m. (midnight) at the start of March 1.
On the next evening, March 2, the crescent will be higher and very easy to spot with the unaided eye. Look for earthshine—illumination from sunlight reflected by the Earth onto the moon’s dark (non-sunlit) side. Watch the crescent thicken daily as it moves farther from the sun on each successive evening, passing the Pleiades star cluster at nightfall on March 6, and within 3 degrees above Aldebaran by the next evening. The moon reaches first quarter phase, half full and 90 degrees from the sun, between the evenings of March 7 and 8.
Finally, the full moon on Sunday, March 16, rises about 20 minutes after sunset, and at mid-twilight is 3 degrees up and 6 degrees south of east. You can continue following the moon for four more evenings by waiting for its rising about an hour later each night—or you can switch your viewing time to morning.
March 2014 at dawn: The brightest objects in morning twilight, in order of brilliance, are: Venus in southeast, slowly fading from its February peak brilliance, and now appearing as a roughly “half moon” through telescopes; Mars in the southwest to west-southwest; Arcturus high in the west; Vega high in the northeast; andSaturn in the south-southwest to southwest. Late in month, Mercury, low in the east-southeast to east, brightens to outshine Arcturus, but it drops very low in bright twilight as it approaches the far side of the sun.
Mars and Spica are 6 degrees apart on March 1, closing to 5 degrees on March 20, and to a least-separation of 4.8 degrees on March 25 and 26, in the second of three conjunctions within six months. Their final pairing, just 1.3 degrees apart, will occur in the evening sky on July 13.
Near Vega are Altair to its lower right, and Deneb to its lower left, completing the Summer Triangle.
To the left of the Mars-Spica pair lies a yellowish point of light glowing steadily: A telescope reveals the rings of Saturn, now tipped over 22 degrees from edge-on! Extend the Mars-to-Saturn line to the left of Saturn and drop down a bit, and you’ll find reddish twinkling Antares, heart of the Scorpion.
The moon can be followed in morning twilight in the latter half of March. It starts its journey as a full moon low in the west on March 16. Within a week, passing through the southwestern quadrant of the sky, it appears near Mars-Spica on March 18 and 19, near Saturn on March 20 and 21, and well above Antares on March 22. The moon passes last-quarter phase, half full, between the mornings of March 23 and 24. A waning crescent, the moon appears in a beautiful pairing with Venus in the southeast on March 27, and next, widely above and then left of Mercury on March 28 and 29. The last old crescent will appear very low, just south of east in bright twilight, on March 29. The second new moon of this month occurs on the 30th at 11:45 a.m.
Evening encore: The month ends as it began, with a beautiful young crescent moon low in the western sky at dusk. This one should be easy for unaided eye: Forty minutes after sunset, it will be 8 degrees north of west, 7 degrees above the horizon, and 32 hours old.
Robert C. Victor was a staff astronomer at Abrams Planetarium at Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs. Robert D. Miller, who provided the twilight charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.