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27 Feb 2019

March Astronomy: The Month Brings Beautiful Planetary Sights in the Mornings—and the Start of Spring!

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In March 2019, early risers can enjoy a widening panorama of planets in the southeast quadrant of the sky—from the lower left to the upper right, one hour before sunrise, they are Venus, Saturn and Jupiter.

A waning moon adds its beauty to this section of the sky through March 2, and again March 26 through April 2. Moon pairings with bright Jupiter, the westernmost of the three planets, occur on Feb. 27 and March 27. Since Saturn is currently 26 degrees (two days of moon travel) east of Jupiter, the moon will pass Saturn on March 1 and 29. Venus, the easternmost of the three planets and the brightest, is rapidly moving eastward, so Venus’ pairings with the moon occur on March 2 and on April 2.

After March, Coachella Valley residents won’t catch Venus in a dark sky (in the absence of twilight) again until mid-November, after the planet emerges from its mid-August passage through superior conjunction beyond the sun, and into the evening sky.

Bright stars visible in March’s morning twilight include the Summer Triangle of Vega-Altair-Deneb high in the east; Arcturus and Spica in the southwest to west; and Antares, heart of the Scorpion, in the south, to the right of Jupiter. On mornings in March, we preview all these stars and the slow-moving planets, Jupiter and Saturn, in about the same places in the sky where we’ll catch them on warm July evenings.

Evenings: Find slowly fading Mars in the west at dusk, and watch it approach the Pleiades (Seven Sisters) all month. On March 1, Mars is 20 degrees below the star cluster. On the 31st, the red planet passes only 3 degrees south of the cluster, providing beautiful views for binoculars for about five evenings before and after March 31.

Also in the evening, the Big Dipper’s curved handle, extended, leads the eye to the rising of golden Arcturus in the east-northeast, and blue-white Spica in the east-southeast. When both stars rise before the end of evening twilight, it’s a sure sign that spring has arrived. The season begins astronomically on March 20 at 2:58 p.m., when the sun stands directly over Earth’s equator. Just more than two hours earlier, at 12:54 p.m., midday in Palm Springs, the sun reaches its high point for that day—34 degrees south of overhead (because we’re 34 degrees north of the equator). At dusk in the early spring, all of winter’s brightest stars are still around for evening viewing—see a photo of the Winter Hexagon at https://apod.nasa.gov/apod/ap190117.html—but by early April, all have crossed into the western half of the sky.

Retrograding on the near side of the sun from evening into morning, Mercury still shines at magnitude zero at dusk on March 1, but fades to +1 by March 4 and even more rapidly in the following days, while dropping into the western evening twilight glow. By the 30th, Mercury recovers to first magnitude and begins a poor, horizon-hugging apparition in the morning twilight glow—keep binoculars handy!—low in the east, 12 degrees to the lower left of Venus. Mercury will approach within 5 degrees to the lower left of the brightest planet in a quasi-conjunction April 11-23.

Here is a selection of sights involving solar system bodies:

Through March 3: The waning moon passes Antares, Jupiter, Saturn and Venus at dawn. Watch for close moon-planet pairs. Can you spot the thin, old crescent moon for two more mornings, 8 degrees to the lower left of Venus, on March 3, and 18 degrees to the lower left of Venus on March 4?

The new moon occurs on March 6 at 8:04 a.m. On the following evening, March 7, about 30 to 40 minutes after sunset, can you spot the thin, 2 percent crescent moon, just 34 hours past new? Forty minutes after sunset, it’s only 5 degrees up and 8 degrees south of due west. In clear skies, from places where mountains don’t block your line of sight to the moon, binoculars give an excellent view. Follow the moon daily at dusk until it is full, on March 20.

Tuesday, March 12: Aldebaran, eye of Taurus, is 5 degrees to the upper left of the fat crescent moon at dusk. As the sky darkens, several stars of the Hyades star cluster become visible in the same binocular field. The “V” formed by Aldebaran and the Hyades form the head of the Bull, with Aldebaran at the top of the left side of the “V.” As the evening progresses, watch the moon close in on some of the cluster members. From the Coachella Valley, just a few seconds before 11 p.m., the moon’s leading dark edge will occult, or cover up, one of the Hyades stars, 3.8-mag. Delta-1 Tauri. The occultation will be best observed with a telescope.

March 14, about an hour before sunrise: As you look toward Jupiter in the southern sky, visualize the motion of our Spaceship Earth heading toward that planet at a speed of nearly 19 miles per second. Saturn and Venus also lie ahead of us. We are catching up to Jupiter and Saturn and will overtake them on June 10 and July 9 as we pass between those outer planets and the sun.

March 20: Spring begins at 2:58 p.m. The full moon occurs at 6:43 p.m., and today, the moon sets very near the time of sunrise and rises a few minutes before sunset. Watch the moon rise more than an hour later nightly for the next several evenings, farther south each time. Since this full moon occurs so early in the spring, Easter this year occurs not on March 24, the first Sunday after the first full moon of spring, but on April 21, after the April 19 full moon. This spring, we’ll have four full moons.

March 25-29: The moon passes Antares, Jupiter and Saturn at dawn. The moon and Jupiter are 5 degrees apart on March 27; the moon and Saturn are 4 degrees apart on March 29.

March 29-April 1: Mars passes 3 degrees south of Pleiades at dusk. It’s excellent through binoculars.

Check the website of the Astronomical Society of the Desert at www.astrorx.org for dates and times of our evening star parties at two locations:Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will next have sessions starting at dusk on Saturday, March 2 and April 6. Our primary, more-accessible location is at the Visitor Center of the Santa Rosa and San Jacinto Mountains National Monument (on Highway 74, within 4 miles south of Highway 111 in Palm Desert). Our next session there is on Saturday, March 16, at 7 p.m.

Remember to check the Impromptu Star Parties link on the Astronomical Society’s webpage. I’ll be offering sky watches in Palm Springs at the pedestrian bridge over Tahquitz Creek at North Riverside Drive and Camino Real, including some in predawn to follow the three morning planets, and some at dawn or dusk to observe moon’s conjunctions with planets.

Abrams Planetarium publishes a monthly Sky Calendar with an evening sky map. Subscriptions are $12 per year at www.abramsplanetarium.org/skycalendar for three printed issues mailed quarterly.

Wishing you clear skies!

Robert C. Victor was a staff astronomer at Abrams Planetarium at Michigan State University. He is now retired and enjoys providing sky watching opportunities for a variety of groups in the Coachella Valley. Robert D. Miller 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.

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