By Robert C. Victor, Robert D. Miller and Dr. Jeffrey L. Hunt

March opens with a spectacular pairing of the two brightest planets at dusk, Venus and Jupiter. They appear closest to each other, just half a degree apart – about the apparent width of the Moon’s disk – on Wednesday, March 1st. They’re still 11°-12° above the western horizon at nightfall, as twilight ends, nearly one and a half hours after sunset. So, if mountains don’t block your view, you’ll catch the brilliant pair in a dark sky, a truly impressive sight! Their background stars of Pisces, the Fishes are no brighter than third magnitude, compared to Venus at mag. –4 and Jupiter at –2, so the planets will really stand out!
 
Celebrate spring 2023 on your early evening strolls. Enjoy observing the changing positions of the Moon and four evening planets against the background of the zodiac constellations.
 
The gibbous Moon, about three-quarters full on March 1, is in the constellation Gemini, 90 degrees east of the planet pair that evening. Note the “Twin” stars Pollux and Castor, 4.5° apart, about 10°-11° east of the Moon on March 1. Mars, of mag. +0.4 in Taurus, is about 22°-23° west of the Moon, or one-quarter of the way from the Moon back toward the Venus-Jupiter pair. Taurus includes some beautiful star fields for binoculars: Aldebaran and the Hyades cluster, making a V-shaped pattern representing the head of the Bull; and the compact Pleiades or Seven Sisters star cluster. Just 4.5° from Mars on March 1 – same as the separation between Pollux and Castor – is the 1.7-mag. star Elnath, marking the tip of the Bull’s northern horn.
 
Watch nightly for changes of the Moon and planets. The Moon, in a more distant part of its orbit in early March, is moving at a somewhat leisurely pace of 12° per day, compared to its average rate of 13.2°. But that’s still much faster than the planets! Venus in March is shifting its position against the background stars by 1.2° per day; Jupiter by 0.2°; and Mars by 0.4°-0.5° daily. 
 
On the evening of Thursday, March 2, the Moon will pass within 2° south of Pollux, while the Venus-Jupiter pair will be separated by 1°. On each successive evening, Jupiter appears lower, and Venus a little higher.

You can trace out the Ellipse on our evening twilight star map by connecting the left end of each of the star trails in the order listed above. (The right end of each trail will work just as well.)
 
If you happen to be in a very dark place, with very low effects of light pollution from artificial illumination, look toward the western sky as twilight ends on clear evenings during March 10-22. That would be about 1.4 hours after sunset. Look for a huge, faint pyramid of light, with its nearly vertical axis along the ecliptic or centerline of the zodiac – roughly a line from Venus toward Mars – broader and brighter near its base and near its axis, and tapering off higher in the sky. You might want to block Venus with your hand or with a tree. It’s the Zodiacal Light, from sunlight reflecting off dust particles in the inner solar system.
 
We’ll come back to the evening sky when the Moon returns on March 22. But keep track of Jupiter until then, because it will come in handy to locate the thin returning lunar crescent, and a few days later, the innermost planet, Mercury, emerging from the far side of the Sun.
 
After the switch to daylight saving time on Sunday, March 12, you won’t have to get up so early to see a dark predawn sky. Use the morning twilight chart in the online version of this article about an hour before sunrise to find these six bright stars: the Summer Triangle of Vega, Altair, and Deneb well up in the east; reddish Antares, heart of the Scorpion, in the south; and golden Arcturus high in the southwest, with blue-white Spica, spike of grain in the hand of Virgo, below. Watch the waning Moon pass above Spica on Fri. March 10, and hopscotch from west of Antares to east of it on March 13 to 14. By Sat. March 18, Saturn emerges very low in ESE, 17°-18° lower left of a 14-percent crescent Moon. On Sunday, March 19, the old, 7-percent crescent Moon appears 2° lower right of 0.9-mag. Saturn.
 
On Monday, March 20, as the Sun passes from south to north of the equator at 2:24 p.m. PDT, spring begins in Earth’s northern hemisphere.
 
By Wednesday, March 22, three weeks have elapsed since the close pairing of Venus and Jupiter on March 1. Look in the west about 30-40 minutes after sunset for the thin, 3-percent crescent Moon within 18° lower right of Venus. Jupiter will be 2° to 3° to the lower right of the Moon. Tonight’s crescent Moon marks the beginning of the month of Ramadan for followers of Islam. One month of daily fasting from sunrise to sunset begins on Thursday. Continue to track departing Jupiter, because in a few days, it will help you locate emerging Mercury.
 
Follow the Moon daily at dusk, and watch for these events:

• Thursday, March 23, Moon 5° below Venus;
• Friday, March 24, Moon 7° above Venus.
• Saturday, March 25, Moon within 2° S of Pleiades.
• Sunday, March 26, Moon 9° N of Aldebaran and 17-18° W of Mars. Mars has crossed from Taurus into Gemini. Jupiter 24° lower right of Jupiter. Mercury 2.3° lower right of Jupiter.
• Monday, March 27, Mercury (mag. –1.4) passes 1.3° N (right) of Jupiter. Look for the pair 25° lower right of Venus. Mars within 6° upper left of the Moon, now a fat crescent, 41 percent full.
• Tuesday, March 28, Mars within 7° lower right of the First Quarter Moon, which is half full and 90 degrees, or one quarter-circle east of the Sun. Jupiter, now 2.0° lower left of Mercury, appears lower each evening and will very soon disappear into the Sun’s glare. Mercury appears a little higher each night, until April 11, when it reaches its best position in the evening sky for this year.
• Wednesday, March 29, Moon 3° to 5° from the Twin stars, Pollux and Castor. Can you still spot Jupiter, 3.5° lower right of Mercury? At nightfall, using binoculars, try for 6th-magnitude Uranus 1.5° upper left of Venus.
• Thursday, March 30, Moon, 69 percent full, is 9° to 13° east of the Twins. Using binoculars at nightfall, try for Uranus within 1.3° lower left of Venus.

Illustrations of many of the events described here, including nightly views following the March 1 conjunction of Venus-Jupiter, appear on the March 2023 Sky Calendar accompanying this article. Subscription info and another sample issue are available at Abrams Planetarium Sky Calendar.

Illustrations accompanying the article on March skies:

• March Sky Calendar      SkyCal202303Mar2023.pdf
• March Evening Skies    SkyMap202303Mar2023.pdf

 All-sky twilight charts, by Robert D. Miller:

• S202303P.pdf = evening twilight sky map for southern California (lat. 34N).
• S202303A.pdf = morning twilight sky map for southern California.

These charts plot daily positions of planets and bright stars at mid-twilight, when the Sun is 9° below the horizon, about 40 minutes after sunset or 40 minutes before sunrise in March from latitude 34° north.
 
Graphs showing setting times of Moon and planets in evening sky and rising times of Moon and planets in morning sky by Jeffrey L. Hunt, calculated for Chicago, but still useful for California:

• 2023_Chicago_evening_planets.pdf
• 2023_Chicago_morning_planets.pdf

Examples of information which can be gleaned from these charts:
 
From graph of evening planet setting times:
Venus and Jupiter set together 0.5° apart in a dark sky, after the end of twilight, on March 1.
After their conjunction on March 1, Venus sets later each evening, while Jupiter sets earlier, and closer to the time of sunset, eventually sinking into bright twilight.
Jupiter and Mercury set together in twilight on March 27, when they are 1.3° apart.
Mercury's best evening appearance of the year 2023 occurs in April.
Venus sets latest after sunset in May 2023. In July, Venus' setting time rapidly moves closer to the time of sunset.
 
From graph of morning planet rising times:
Venus starts rising before the Sun in August, and rises earliest before sunrise in 2023 in late October.
Mercury's best appearance in the morning sky in 2023 occurs in September.

April is a good month for students to start keeping a checklist of bright stars seen each evening, within the first hour after sunset. Many bright stars are gathered in the western sky, including the huge Winter Hexagon. In clockwise order, starting with Sirius, its brightest and southernmost member, its stars are Sirius, Procyon, Pollux and Castor, Capella, Aldebaran, Rigel, and back to Sirius. Striking changes in the visibility of these stars will occur in late spring, as a result of the Earth’s revolution around the Sun. Students can list their sightings of the Moon and planets, and the Pleiades star cluster too! An observer’s log is provided here.

• DailySkywatchLog.pdf

Continue recording your observations in the Daily Skywatch Log until at least the middle of June, when only a few stars from the initial list will remain, along with Venus and Mars in 2023.

The following evening twilight charts will follow the changing positions of planets and bright stars until the end of August.

• April 2023:        S202304P.pdf
• May 2023:     S202305P.pdf
• June 2023:         S202306P.pdf
• July 2023:          S202307P.pdf
• August 2023:    S202308P.pdf

For those who might enjoy observing the predawn sky, here are morning twilight charts. Face the eastern sky to watch for the first dawn appearance of stars and planets.

• April 2023:        S202304A.pdf
• May 2023:     S202305A.pdf
• June 2023:         S202306A.pdf
• July 2023:          S202307A.pdf
• August 2023:    S202308A.pdf

Watch this space for Sky happenings for April, May, and June, which will be added in time for those months.
In the meantime, here are the Sky Calendar and the Evening Skies star chart for April 2023. Note that the chart, April Evening Skies, shows all the bright stars listed in the Daily Skywatch Log which are slated to sink into bright twilight before the end of June.

• April Sky Calendar      SkyCal202304Apr2023.pdf
• April Evening Skies    SkyMap202304Apr2023.pdf

Robert C. Victor originated the Abrams Planetarium monthly Sky Calendar in October 1968 and still produces issues occasionally. He enjoys being outdoors sharing the beauty of the night sky and other wonders of nature.

Robert D. Miller, who provided the evening and morning 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.

Dr. Jeffrey L. Hunt. who provided the graphs of planet rising and setting times for 2023, is a retired planetarium director now living in the Chicago area. He has taught astronomy and sky watching to people of all ages. He studied astronomy education at Abrams Planetarium at Michigan State University. Jeffrey writes an astronomy blog at jeffreylhunt.wordpress.com and can be followed on Twitter at @jeff_hunt.
 

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