March 28, 2023 (SFChronicle.com)
Bay Area stargazers will want to look skyward just after sunset this week: a rare “parade” of five planets will be visible, weather permitting, plus a star cluster and the crescent moon.
Though the “planet parade” could be visible after sunset for the next few days, sooner is better than later, Paul Lynam of the Lick Observatory on Mount Hamilton said.
The celestial show should be set to begin 20 minutes after the sun sets, or just before 8 p.m., according to astronomer Joe Rao. He writes that the celestial objects will appear in the following order and go from left to right in the western sky: the star cluster Messier 35, Mars, the moon, Uranus, Venus, Jupiter and Mercury.
Finding planets in the sky
Bright Venus, at the center of the show, will be the easiest planet to see. But right away, you should aim for a glimpse of Jupiter and Mercury, Rao advises in a column for Space.com, because they will be the first to disappear.
The two planets will be side by side, below and to the right of Venus, near the horizon where the sun just set, with Jupiter about twice as bright as Mercury, according to Rao.
“Mercury happens to be lined up near Jupiter on the sky — a cosmic photobomb, as it were! — so people will be able to try and spot Mercury in the bright sky just to the right from Jupiter,” said Geoff Mathews, an astronomer at Foothill College in Los Altos Hills, in an email. “It will definitely be a race between the planets setting and the sky getting darker!”
Slightly above and to the left of Venus will be Uranus, shining a faint pale green, Rao says. To find Mars, first locate the crescent moon; the glowing object to its upper left will be the Red Planet.
The Messier 35 star cluster will be to the upper left of Mars, Rao says. Called M35 for short, the cluster located in the constellation Gemini appears as a curving formation of faint lights, with a reddish star at the center.
Where and when to see the planet parade
Getting a glimpse of all of this could be a challenge. Monday night was probably the best chance, but not the only one.
“The positions of the planets on the sky change only gradually, so it is rare for an event to be ‘one night only,’ ” Mathews said. “(Monday) is when Mercury and Jupiter appear closest to each other in the sky, but their positions will change slowly over the next few nights.”
“If anything, over the next few days the chances of seeing Mercury with the naked eye will only improve, as it will keep moving up on the sky compared to Jupiter, thus setting below the horizon a little bit later in time when the sky is darker,” he added.
If the sky is clear, Rao recommends going to a flat, wide-open place with an unobstructed view of the horizon — ideally, a westward-facing shoreline. While the moon and brighter planets can be seen without special gear, a good pair of binoculars or small telescope is needed if you want to find the fainter celestial bodies like Uranus, as well as Jupiter and Mercury.
To see the last two, Rao advises first sweeping low across the western horizon with binoculars just after sunset. When you find them, try looking with just your eyes. And enjoy it while it lasts — about 30 minutes at most, Rao says, after which both planets will set below the horizon.
All the planets, including Earth, orbit in close to the same plane, Mathews said, and therefore appear to us to move in the same line across the sky.
Planetary alignments occur when a group of planets line up on one side of the sun from the Earth’s perspective, NASA astronomer Bill Cooke told the Associated Press. They can involve different planets in different numbers, and while they are not uncommon, some types are rarer than others.
In this case, for example, “Seeing five planets with the crescent moon is unusual,” said Andrew Fraknoi, emeritus chair at the Foothill College Astronomy Department.
The planetary alignment that occurred June 6 of last year involved the “naked eye” planets of Mercury, Venus, Mars, Jupiter and Saturn, which are viewable without equipment and appeared in sequential order from the sun — an event that hadn’t happened since 2004 and won’t occur again until 2040.
Another five-planet alignment will appear in June, according to stargazing app maker Star Walk, involving Mercury, Uranus, Jupiter, Neptune and Saturn.
Mathews noted that for those wanting a closer view of the planets, the Foothill College observatory at 4100 Perimeter Road in Los Altos Hills is open Fridays from 9 to 11 p.m., weather permitting. Viewing and parking are free.
The Chronicle’s Annie Vainshtein contributed to this report.
Reach Anna Buchmann: anna.buchmann@sfchronicle.com
Written By Anna Buchmann
Anna Buchmann is The San Francisco Chronicle’s engagement editor. She joined the newsroom staff in 2019 as an online producer for SFChronicle.com. Previously, she worked at The Sacramento Bee in a variety of roles, including digital senior editor, senior editor for topics and breaking news, regional news desk director and copy desk chief. She also trained newsroom reporting interns in the fundamentals of journalism. Buchmann began her journalism career at the San Jose Mercury News, where her roles included news editor, wire editor, copy editor, page designer and education reporter. She earned her bachelor’s degree in English literature from Georgetown University and her master’s degree in journalism from Stanford University, where she also taught editing in the journalism M.A. program.
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