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Last updateTue, 18 Sep 2018 1pm

Robert Victor

Brilliant Venus (magnitude -4.0) and fainter Saturn ( +0.5) are 4.5 degrees apart in the southwest at dusk on Nov. 1, but Venus speeds away while Saturn sinks into the solar glare, widening the gap between them to nearly 15 degrees by Nov. 11, and to 22 degrees by Nov. 18. Use binoculars to watch Venus pass background stars in Ophiuchus and Sagittarius on Nov. 4, 16, 17, and 22. Venus sets farthest south Nov. 14. By month’s end, Venus brightens to magnitude -4.2 and is noticeably higher than it was at the start of November. A telescope shows Venus in gibbous phase, 70 percent full at month’s end. Wonderful changes will happen in coming months, before Venus departs from the evening sky in late March.

Mercury (magnitude -0.5) passes 3.5 degrees south (to the lower left) of Saturn on Nov. 23, but they’ll both be very low in the twilight glow, with Mercury brighter. Using binoculars, look 27 degrees to the lower right of Venus. Replacing Saturn, Mercury is 25 degrees to the lower right of Venus on Nov. 30, and will hold 24 degrees to the lower right of Venus Dec. 2-12.

Look for dim Mars (magnitude +0. 4 to +0.6) in the south to south-southwest, to the upper left of Venus, by 37 degrees on Nov. 1; 30 degrees on Nov. 16; and 24 degrees on Nov. 30. Watch Mars pass third- and fourth-magnitude stars in Capricornus, the sea-goat, on Nov. 14 and 27, and on Dec. 10.

In the morning sky in the east-southeast to southeast, find bright Jupiter, magnitude -1.7 to -1.8. As the sun withdraws east of Jupiter this month because of Earth’s faster revolution around the sun, the giant planet ascends higher in predawn. Note the first-magnitude star Spica in Virgo, 13 degrees to 8 degrees below bright Jupiter.

The moon, as a waxing crescent in evening sky, can be seen in a pretty gathering with Venus and Saturn on Nov. 2; near Mars on Nov. 5 and 6; near Mercury on Nov. 30; near Venus on Dec. 2 and 3; and near Mars on Dec. 4 and 5. In the mornings, follow the waning moon, near Aldebaran, eye of Taurus, on Nov. 15; near Pollux, brighter of the Gemini twins, on Nov. 18; near Regulus, heart of Leo, on Nov. 21; near Jupiter on Nov. 24; and near Spica and Jupiter on Nov. 25.

The full moon, on Monday, Nov. 14, at 5:52 a.m., follows the moon’s perigee (closest approach to Earth) by only 2.5 hours. The resulting “Supermoon” is the closest until Nov. 25, 2034. (Get ready for the inevitable hype in the news media!) The next “Supermoon” closer than that one will occur on Dec. 6, 2052—the best of the 21st century. The moon this month will be closest for observers in the Coachella Valley on the night of Sunday, Nov. 13, just a few minutes after the moon reaches its highest point in the south, at 11:20 p.m., and, contrary to appearances, not when the moon is rising on Sunday around 4:33 p.m. or setting Monday morning around 6:11 a.m. (The moon just seems larger at rising or setting than when it is high in the sky. It’s called the “moon illusion.”) Also, this is not the brightest full moon of this year. That’s because this month’s full moon passes widely south of Earth’s shadow, and does not reflect as much light toward us as it would if the moon narrowly missed the shadow. The sharp brightening of the moon or an asteroid when it appears almost exactly 180 degrees from the sun is sometimes called “the opposition effect,” or “opposition surge.”

Star parties provide wonderful opportunities to join with other folks who love to share their interest in observing the sky, and to get great views of astronomical objects through a variety of binoculars and telescopes. The first two events, happening this weekend, are annual gatherings not far from the Coachella Valley: The 2016 Nightfall Star Party takes in Borrego Springs Oct. 27-30, while the 2016 Joshua Tree National Park Night Sky Festival is Oct. 28-30.

Local star parties (in and near the Coachella Valley): The Astronomical Society of the Desert will host the next of our series of monthly star parties on Saturday, Nov. 5, from 6 to 9 p.m., and on Saturday, Dec. 17, from 5 to 8 p.m. They are held at the Visitor Center of the Santa Rosa and San Jacinto Mountains National Monument, on Highway 74, within four miles south of Highway 111 in Palm Desert. Check the society’s website at www.astrorx.org for listings of our regular star parties at the Visitor Center, and our high altitude star parties at Sawmill Trailhead starting at dusk. The next high-altitude star parties (at 4,000 feet—wear warm clothes!) will be held on Saturday, Nov. 19, and on Saturday, Dec. 3. Follow links to maps and directions to both star party sites, and for dates and locations of lecture meetings. Also, check the link to our “Impromptu Star Parties,” which could be announced on short notice at any time.

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 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.

On Thursday morning, Sept. 29, a beautiful sight will reward early risers who go out to enjoy the brightening dawn 45 minutes to an hour before sunrise: About 5:45 a.m. in the Coachella Valley that morning, very low, almost directly east, a slender, crescent old moon will be suspended just 2 degrees below Mercury.

Other sights in the morning sky through October include Sirius, the brightest star, well up in the south-southeast, and the rest of the Winter Hexagon’s stars—in clockwise order, Procyon, Pollux (and Castor, not shown), Capella, Aldebaran and Rigel, with Betelgeuse inside. Other bright stars include Canopus, very low in the south, the second brightest star (easier to see later in the month, when it reaches its high point, due south, earlier in a darker sky), and Regulus, heart of Leo, the Lion, in the east.

The old moon of Sept. 29 is followed by the new moon on Fri. Sept. 30 at 5:11 p.m., invisible as it passes close to the sun. The next chance to see the moon is on the evening of Saturday, Oct. 1, only about 20 to 30 minutes after sunset. With all the mountains around us, you must choose your vantage point carefully, because about 20 minutes after sunset in the Coachella Valley, or about 6:50 p.m., the very slender crescent will be only 3 to 4 degrees up. Binoculars will help. Look for the hairline crescent 9 degrees south of due west and 20 degrees to the lower right of Venus. This crescent moon is special, because its sighting marks the beginning of the first month of the new year of the Islamic calendar.

The moon will be much easier to spot as it thickens, appears higher, and sets more than half an hour later nightly. On Sunday, Oct. 2, the moon will be 10 degrees to the lower right of Venus. On Monday, Oct. 3, the moon will pass within 5 degrees to the upper right of Venus, and on Tuesday, the moon will appear 13 degrees to the upper left of Venus. On Oct. 5, the moon passes within 5 degrees to the upper right of Saturn, and on Friday the 7th, the moon will be 7 degrees to the upper right of Mars.

Besides these three planets, other prominent objects at dusk include golden Arcturus sinking in the west, and blue-white Vega northwest of overhead, with Deneb and Altair, completing the Summer Triangle.

The full moon of Saturday, Oct. 15, rises just north of due east a few minutes after sunset that evening. The waning moon rises later each night, shifting farther north along the horizon nightly through Oct. 20.

In the Coachella Valley at 9 p.m. on the evening of Tuesday, Oct 18, binoculars will show a bright star within one degree to the lower left of the moon, just risen in the east-northeast. By 10:19 p.m., the sunlit edge of the moon will cover first-magnitude Aldebaran, eye of Taurus, the Bull. Aldebaran remains hidden by the moon until 10:35 p.m., when the star reappears along the northern part of the moon’s dark edge. Even though this is the brightest star the moon can occult (cover), a telescope will be needed to observe the star disappear and reappear, since the moon is very bright—only three days past full.

Watch the planets move! In the evening sky in October, Venus goes east 1.2 degrees per day against background stars, while Mars goes east about 0.7 degrees daily. Follow their progress easily from one night to next for several evenings around dates when planet passes a star. Track Venus for a few evenings around following dates when it passes close to a background star: Oct. 5, when Venus passes 0.8 degrees to the lower left of third-magnitude Alpha in Libra, also known as Zubenelgenubi, the southern claw of an early, larger version of the Scorpion; Oct. 20, when Venus passes within 1 degrees above second-magnitude Delta Scorpii, the middle of the three stars in the head of the Scorpion; Oct. 26, when Venus passes 3.1 degrees north (to the upper right) of first-magnitude Antares; and Oct. 29, when Venus passes 3.0 degrees south (to the lower left) of Saturn.

Watch Mars on Oct. 6, as it passes 0.2 degrees below third-magnitude Lambda Sagittarii, marking the top of the Teapot. This star is also known as Kaus Borealis, northern star of the Archer’s bow. On Oct. 15, Mars passes within 1.3 degrees north (to the upper right) of second-magnitude Nunki, or Sigma in Sagittarius, brightest star in handle of the Teapot.

Saturn, the only other bright evening planet, moves only 2.7 degrees east during Oct. 1-31, averaging less than 0.1 degrees per day.

In the mornings: Just before the start of twilight Sept. 29-Oct. 12 and Oct. 29-Nov. 11, from a very dark place, try to see the zodiacal light—from sunlight reflected off comet and asteroid dust in the plane of the solar system. Look for a huge pyramid of faint light extending upward from the eastern horizon toward the star Regulus in Leo.

Low in the east during morning twilight in October, bright, emerging Jupiter replaces Mercury. Using binoculars about 40 minutes before sunrise, see both planets for a few days around Oct. 11. The best mornings are Oct. 10-12: The planets are 1.5 degrees apart on Oct. 10, with Jupiter to the lower right of Mercury. They appear closest, 0.8 degrees apart, on Oct. 11, with Jupiter to the south (right) of Mercury. They’re 1.9 degrees apart on Wednesday, Oct. 12, with Jupiter to the upper right.

On Friday, Oct. 21, in the predawn darkness hours, watch for the peak of the Orionid meteor shower, consisting of particles from Halley’s Comet.

On Friday, Oct. 28, a waning crescent moon, two days before new, will appear 2-3 degrees to the lower left of Jupiter in morning twilight. On Saturday morning, Oct. 29, the last old crescent will appear 14 degrees to the lower left of Jupiter. Binoculars will help you pick out emerging Spica, just five degrees to the lower right of the delicate crescent. The new moon occurs on Sunday, Oct. 30, at 10:38 a.m.

On Monday evening, Oct. 31, 40 minutes after sunset, the young crescent moon will be 3 degrees up in the west-southwest, 24 degrees to the lower right of Venus.

The Astronomical Society of the Desert will host the next of our popular series of monthly star parties on Saturday, Oct. 8, from 7 to 10 p.m. They are held 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. Check www.astrorx.org for listings of our high altitude star parties at Sawmill Trailhead starting at dusk. The next one will be held on Saturday, Oct. 22. Visit the website for maps and directions to both star party sites, and for dates and locations of lecture meetings. Also, follow the link to our “Impromptu Star Parties, which could be announced on short notice at any time.

Also, don’t miss the 2016 Joshua Tree National Park Night Sky Festival on Oct. 28-30 and the 2016 Nightfall Star Party in Borrego Springs Oct. 27-30.

The Wildlands Conservancy’s Whitewater Preserve at 760-325-7222 and the Pioneertown Mountains Preserve at 760-369-7105 occasionally host star parties. The next one at Pioneertown Preserve is set for Oct. 8. Reservations required; call the appropriate preserve.

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 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.

Our evening twilight chart for September, depicting the sky about 40 minutes after sunset, shows brilliant Venus remaining low, creeping from west to west-southwest and gaining a little altitude as the month progresses. Its close encounter within 2.5 degrees north of Spica on Sept. 18 is best seen with binoculars to catch the star low in bright twilight.

The brightest stars in the evening sky are golden Arcturus, descending in the west, and blue-white Vega, passing just north of overhead. Look for Altair and Deneb, completing the Summer Triangle with Vega. The triangle of Mars-Saturn-Antares expands as Mars seems to hold nearly stationary in the south-southwest as the month progresses, while Saturn and Antares slink off to the southwest.

The morning twilight sky is rich with stars as the Winter Hexagon, made up of stars from Orion, his Dogs, the Twins, the Charioteer with Mother Goat, and Taurus, the Bull. Tracing out the Hex starting with Sirius, the brightest star, going clockwise, we encounter Procyon, Pollux (and nearby Castor, not quite first magnitude, and therefore not bright enough to be plotted), Capella, Aldebaran, Rigel and back to Sirius. Inside the Hexagon lies Betelgeuse, Orion’s shoulder. The Summer Triangle’s Deneb sinks into the northwest. Regulus, Leo’s heart, emerges into the east-northeast early in the month and is well up in the east by month’s end. By Sept. 22, emerging Mercury approaches within 15 degrees below Regulus. Brightening rapidly, in its best-of-year morning appearance, Mercury reaches peak altitude just before month’s end. Can you spot the second-brightest star, Canopus, before month’s end? It’ll be easier in October, when the star reaches its high point in the south (only 3 degrees up!), four minutes earlier each day, in ever-darker morning skies. Choose your vantage point carefully, with no high mountains nearby to your south.

There are two new moons in September: on Sept. 1 at 2:03 a.m., and on the 30th at 5:11 p.m. That means that this month, we can observe a complete cycle of the moon from start to finish, starting as a thin crescent moon very low in the west at dusk on Sept. 2, and waxing through the first half of the month, until it becomes full on the 16th. Next, we can follow the waning moon in the morning sky through Sept. 29. There are many striking events, starting with a close pairing of Jupiter and a young crescent moon on Friday, Sept. 2. Early that evening, get to a place with an unobstructed view toward west by 25 minutes after sunset, and look for Jupiter and the crescent moon, about 5-6 degrees to the lower right of Venus. Binoculars will help! From the Coachella Valley, the moon occults, or covers, Jupiter that afternoon, from 2:50-3:44 p.m., but the event will be impossible to see in the daylight, as it occurs only 18 degrees from the sun.

Watch the moon pass planets, as shown on the Abrams Planetarium Sky Calendar. By Saturday. Sept. 3, the moon is easy to spot, about 6 degrees to the upper left of Venus. On Sunday, Sept. 4, look for Spica 5 degrees to the moon’s south (lower left). Binoculars will help. Wait for the sky to darken some, but don’t wait too long, or Spica and the moon will set! Don’t miss the moon sliding past the beautiful triangle of Saturn, Antares and Mars on the evenings of Sept. 8 and 9. (See above right.)

The full moon on Friday, Sept. 16, comes up within 15 minutes after sunset. It’s fun to watch moonrises, and on the next five nights, the moon rises about 40-50 minutes later each night.

Beginning Sept. 17, you can shift your viewing times to mornings, about an hour before sunrise, and catch the moon passing by bright zodiacal stars: Aldebaran in Taurus on Sept. 21 and 22; Pollux and Castor in Gemini on Sept. 24 and 25; and Regulus in Leo on Sept. 27 and 28. On the moon’s final morning, Sept. 29, the old crescent moon will appear low in the east, just 2 degrees below Mercury.

A tip for telescopic observation of the moon in daytime: When the moon is within two days before or after half full—this month, late in the afternoons of Sept 7-10, near first quarter phase, and on mornings of Sept 21-24, near last quarter phase—insert a single polarizing filter into a low-power eyepiece of your telescope. Next, while viewing the moon, rotate the eyepiece until the surrounding blue sky appears darkest, increasing contrast of the moon against the sky for wonderful views of lunar craters! (Threaded polarizing filters and threaded eyepieces can be obtained from Orion at telescope.com.) I often enjoy setting up my telescope at schools before the school day begins on mornings in autumn, on days when the moon is near last quarter phase and high in the sky.

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 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.

August 2016 has a rare gift for skywatchers: For most of the month, all five naked-eye planets can be seen during evening twilight, and they participate in beautiful pairings and groupings!

From a site with an unobstructed view of the western horizon, begin within a half-hour after sunset to catch Venus before it sinks too low. Use our evening twilight chart link to guide you. Venus, at magnitude -3.8, is visible with the unaided eye, even low in bright twilight, if you know where to look. (It will get higher in coming months, setting in a dark sky starting in October.)

Jupiter, next in brightness at magnitude -1.7, is easy to find not long after you spot Venus. For most of August, Jupiter appears to the upper left of Venus, getting one degree closer each day until their spectacular close pairing on Saturday, Aug. 27. Thereafter, Jupiter will appear to the lower right of Venus, getting increasingly difficult to see.

Use binoculars all month, if necessary, to catch Mercury, starting August at mag -0.1 while 8 degrees to the upper left of Venus, and fading to magnitude +0.5 by Aug. 24 while 6 degrees to the lower left of Venus.

As the sky darkens, Mars (magnitude -0.8 to -0.3), Saturn (+0.3 to +0.5), and first-magnitude Antares—6 degrees from Saturn all month—become easy for the unaided eye to see. The two planets and the red supergiant star will have a striking arrangement Aug. 23 and 24.

In morning twilight Aug. 4-14, look daily within an hour before sunrise and watch for the first appearance of Procyon, about 6-7 degrees north of east, and Sirius, in the east-southeast. The “Dog Star” Sirius is nearly in line with Orion’s belt, and completes the almost equilateral Winter Trianglewith Betelgeuse (Orion’s shoulder) and Procyon. The name Procyon means “before the dog,” because the star rises several minutes before Sirius does, and so gives notice of the imminent rising of the Dog Star. The heliacal rising (first morning appearance) of Sirius was a very important event in ancient Egypt, as it gave notice of the imminent flooding of the Nile River, which occurred around the summer solstice. Now, because of precession, the 26,000-year wobble of the Earth’s axis, the first appearance of Sirius occurs several weeks after the start of summer and the rise of the Nile.

Aug. 4, beginning 30 minutes after sunset: Find the 2.3-day-old crescent moon low in the west, and Venus 11 degrees to its lower right. Mercury appears 2 degrees to the left of the moon, nearly 9 degrees to the upper left of Venus, and 15 degrees to the lower right of Jupiter. Mars and Saturn are 10 degrees apart in the southern sky. Six solar system bodies—Venus-Mercury-moon-Jupiter-Mars-Saturn—span 100 degrees.

Aug. 5: Jupiter is about 1 degree above the moon.

Aug. 6: Three planets, Jupiter-Mercury-Venus, appear 12 degrees, 24 degrees and 33 degrees to the lower right of the moon. Mars and Saturn appear 57 degrees and 65 degrees to the moon’s upper left. Venus and Mars appear 90 degrees apart—in quadrature—this evening. Verify that by observation!

Aug. 7 and 8: The moon is near Spica, brightest star in Virgo.

Aug. 8 and 9: Mars is 0.9 degrees from Delta Scorpii, the middle and brightest of three stars in the head of the Scorpion.

Aug. 10: The moon passes first quarter phase at 11:21 a.m. Tip for telescopic observation of the moon in daytime:When the moon is within two days before or after half full—this month, on the afternoons of Aug. 8-11, near first quarter phase, and on mornings of Aug. 23-26, near last quarter phase—thread a singlepolarizing filter into a low-power eyepiece of your telescope. Next, while viewing the moon, rotate the eyepiece until the blue sky surrounding the moon appears darkest, increasing contrast of the moon against the sky for wonderful daytime views of lunar craters and other features!

Aug. 11-12: As darkness falls, note the beautiful diamond-shaped arrangement of moon-Mars-Antares-Saturn, about 6-7 degrees on each side. The peak of the Perseid meteor shower occurs after moonset, in Friday, Aug. 12’s predawn darkness hours! The dark, moonless sky should be wonderful for observing meteors.

Aug. 12: The moon is 8 degrees to the upper left of Saturn. The famous ringed planet marks the top vertex of an attractive triangle of three “stars.” Compare the color and brightness of its two other members, Mars and Antares. Venus is 15 degrees to the lower right of Jupiter, getting a degree closer each day!

Aug. 16: Mercury is at its greatest elongation, 27 degrees east of the sun. Since Mercury is more to the left of the setting sun, rather than high above it, the planet sets well before darkness falls; this is an unfavorable apparition for observers at mid-northern latitudes, despite Mercury’s unusually large angular distance from the sun. Here in Southern California, we will have an easier time spotting it than folks in northern part of the state.

Aug. 17-18: Venus is 10 degrees to the lower right of Jupiter at dusk. Five planets span 84 degrees. Also, the full moon occurs overnight, at 2:26 a.m. on the 18th. The moon shines with enhanced brightness in that hour as it narrowly misses the penumbra of Earth’s shadow and reflects sunlight toward us.

Aug. 19: Mercury is 3.8 degrees to the lower left of Jupiter, their minimum distance apart in a quasi-conjunction.

Aug. 22: Venus is 4.9 degrees to the lower right of Jupiter.

Aug. 23: Venus and Jupiter are within 3.9 degrees; Mercury and Jupiter 4.3 degrees; and Mercury and Venus 6.4 degrees, in a nearly isosceles triangle.

Aug. 23 and 24: In order from top to bottom, Saturn, Mars and Antares nearly line up, as Mars goes 4.4 degrees south of Saturn and 1.8 degrees north of Antares!

Aug. 25, predawn (using a telescope): The moon occults 3.7-magnitude Gamma Tauri, point of “V” of Hyades star cluster, from 1:17-2:10 a.m. in the Coachella Valley. The daytime occultation of Aldebaran is visible through a telescope: Disappearance on the moon’s bright side occurs in here at 10:24 a.m., with reappearance at the moon’s dark side at 11:27 a.m. Last quarter phase occurred on Aug. 24, at 8:41 p.m., so the moon on Aug. 25 is a fat crescent. Follow waning moon mornings through Aug. 31.

Aug. 25: Venus and Jupiter are within 1.8 degrees.

Aug. 26: Venus and Jupiter are within 0.8 degrees.

Aug. 27:This is the first evening Jupiter appears to the lower right of Venus. The planets are just 0.2 degrees apart, as seen from California—and about 0.1 degrees apart from the Eastern U.S. Alert your friends in that part of the country! Mercury, faded to magnitude +0.8, appears 5.1 degrees south (to the lower left) of the bright pair, and may be missed.

Aug. 28: Venus and Jupiter are 1.2 degrees apart. Their separation increases by about 1 degree daily. Venus and Mercury are 5 degrees apart, the minimum distance for this passage.

Aug. 31: Venus and Jupiter are 4.3 degrees apart, with Jupiter getting lower each evening. On what date will you last spot Jupiter?

Sept. 1: The new moon occurs at 2:03 a.m.

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 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.

All three bright outer planets remain prominent in the evening sky this July.

At dusk, find bright Jupiter in the west-southwest to west, apricot-colored Mars in the southern sky, and Saturn not far to the left of Mars. Venus passed behind the sun in early June, but by mid-July, it emerges into our early evening sky very low in the west-northwest bright twilight glow, 20 minutes after sunset. Look from a place with a view unobstructed by mountains, and use binoculars to help you spot Venus in bright twilight in its first weeks. Binoculars will reveal Mercury near Venus from mid-July until late August. That’ll bring the total to all five bright planets visible simultaneously!

Attend a star party hosted by one of the local astronomy clubs for telescopic views of Jupiter’s cloud belts and four largest moons; Saturn’s spectacular rings and largest moon Titan; the south polar cap and other markings on Mars; and many deep-sky wonders beyond the solar system, in our Milky Way galaxy, and beyond!

Our chart depicting the sky at evening mid-twilight in July follows positions of naked-eye planets and stars of first magnitude or brighter in the sky when the sun is 9 degrees below the horizon, roughly 45 minutes after sunset. Planets are plotted as dots, one for each day, with labels for dates at weekly intervals.

On this map, you’ll find bright Jupiter starting well up, a little south of due west, at dusk in early July 2016, with faint Regulus, heart of Leo, preceding it as they sink toward the western horizon over the course of the month.

Mars starts a little east of due south at dusk in early July. Note the shape of the triangle it forms with Saturn to its left, and the red twinkling star Antares, heart of the Scorpion, below Saturn. The triangle will shrink in coming weeks.

The Summer Triangle of Vega, Deneb and Altair ascends the eastern sky at dusk in July. Its brightest star, blue-white Vega, marks the top of the triangle. Two other bright stars, golden Arcturus and blue-white Spica, are high in the southwest quarter of the sky.

Mercury and Venus first appear on our evening mid-twilight chart in late July, but if you observe earlier in twilight, some 20 to 30 minutes after sunset, and use binoculars, you can catch their closest pairing very low in the west-northwest on July 16, as Mercury (magnitude -1.0) passes just 0.5 degrees north (to the upper right) of Venus (-3.9). (You’ll need a viewing site where mountains don’t block your view!) On the previous evening, July 15, you can spot Mercury 0.8 degrees to the right of Venus, with the two setting at about the same time. On following evenings, Mercury shifts to the upper right of Venus, and next above it, and then toward Venus’ upper left, with their separation widening. During July 16-Aug. 19, Mercury appears higher than Venus, and sets as much as 18 minutes after Venus during from July 30 to Aug. 4.

Follow the moon: Its day-to-day change in position against the stars, averaging 13 degrees per day, is much more noticeable than that of the planets. Watch the moon change from a thin crescent to just past full July 5-20, while passing the planets and the bright stars plotted on our evening twilight charts. Watch for these events:

Tuesday, July 5: See the first crescent moon, age 40.5 hours after new, half an hour after sunset. Binoculars give fine views of this thin moon very low in the west-northwest, provided mountains don’t obstruct your view. Sighting of this crescent marks the start of a new month, ending the fasting month of Ramadan.

Thursday, July 7: Regulus, heart of Leo, appears closely north of the crescent moon.

July 8 and 9: Jupiter is closely to the upper left of the moon on Friday, then not-so-closely to the lower right of the moon on Saturday.

Monday, July 11: The moon is near first quarter phase. Look for the star Spica, the spike of wheat in hand of Virgo, a few degrees north of the moon.

July 13 and 14: Mars is widely to the lower left of the gibbous moon on Wednesday, and not-so-widely to the lower right of the moon on Thursday.

Friday, July 15: Saturn is closely below the moon. Note Antares, heart of Scorpius, the Scorpion, below Saturn.

Saturday, July 16: A close pairing of Mercury-Venus in bright twilight is described above.

Tuesday, July 19: The moon passes full phase shortly before 4 p.m., and rises in the east-southeast at 7:45 p.m., or 10 minutes before sunset in Palm Springs. Because of our surrounding mountains, you must wait several minutes until the moon’s disk begins to appear.

Watch for the moonrise on subsequent evenings: Wednesday, July 20, at 8:30 p.m.; Thursday, July 21, at 9:12 p.m.; Friday, July 22, at 9:52 p.m.; Saturday, July 23, at 10:31 p.m.; Sunday, July 24, at 11:10 p.m., nearly due east; and Monday, July 25, at 11:49 p.m. You’ll notice the moon rising farther north each night until night of July 30-31, when it will rise in the east-northeast at 3:31 a.m. on Sunday morning, July 31.

Early in July, before the moon gets bright, and again beginning around July 22 or 23—when the waning moon after full starts rising late in the evening—go to a dark location after nightfall and enjoy spectacular views of the summer Milky Way. Follow its path from the “W” of Cassiopeia low in the north-northeast, through the Summer Triangle along the Northern Cross, or neck of Cygnus, the Swan, then down toward the Teapot of Sagittarius to the left of Scorpius in the southern sky. Part of the Milky Way resembles a puff of steam rising out of the spout of the Teapot. From within the Summer Triangle and southward, look for the long Great Rift, where the river of the Milky Way is divided into two streams by clouds of obscuring interstellar dust in the foreground blocking the light of the stars beyond. A pair of binoculars will easily resolve the bright Cygnus Star Cloud (where we look into our own spiral arm, along the neck of the Swan) into multitudes of stars!

Telescopic views of planets: Jupiter’s dark equatorial cloud belts and up to four of the bright satellites discovered by Galileo offer a pleasing view for small telescopes.

Mars, still showing a fair-sized disk after its closest approach in late May, displays surface detail! This month, Mars’ southern hemisphere spring equinox will occur on July 4. Although the south pole of Mars is then on the Martian terminator (day-night boundary), that pole is now tipped 15 degrees out of Earth’s view—the surrounding south polar cap of frozen carbon dioxiode (or its overlying cloud cover) is near its maximum extent, reaching halfway from pole to equator, far enough to spill over the southern limb. So whenever you look at Mars early this summer, you’ll see a bright southern edge to Mars’ disk.

Enjoy Saturn’s rings this summer! They’re now tipped from edge-on by almost the greatest angle possible. Using as high of a magnification as your telescope and atmospheric conditions allow (I often use 200x with my 6-inch reflector), try for the Cassini Division dividing the outer A ring from the broader, brighter B ring. This narrow gap is nearly two-thirds of the way from the inner edge of B toward the outer edge of A. Look also for Titan, Saturn’s largest moon, taking 16 days to complete one circuit about the planet. Its nearly circular orbit is almost nine times as large as the outer edge of Saturn’s A ring, in nearly the same plane as the rings now tipped 26 degrees from edge-on, and so it appears as an ellipse.

Titan will appear farthest west of Saturn on July 3 and 19, and farthest east on July 11 and 27. We are seeing the north face of the rings and of Titan’s orbit, so we’ll see Titan at superior conjunction (the far side of Saturn) four days after it appears farthest to the west, and at inferior conjunction (near side of Saturn) passing south of the planet four days after greatest elongation east.

Venus, just emerged from the far side of the sun, appears tiny and full, and low in twilight. It will become much more interesting for telescopic viewing as it nears the end of its evening apparition.

Predawn sky: There are no morning planets visible to the unaided eye in July. (Uranus and Neptune require at least binoculars and detailed finder charts.) But cooler mornings make for more comfortable sky viewing. As dawn begins to brighten, we find the Summer Triangle well up in the western sky, getting lower as the month progresses. Fomalhaut, mouth of the Southern Fish, is in south to south-southwest, and Capella, the Mother Goat star, is ascending in the northeast. To Capella’s lower right, we find ruddy Aldebaran, eye of Taurus the Bull. Before the sky brightens, look above Aldebaran for the beautiful Pleiades star cluster (the Seven Sisters), a wonderful target for binoculars!

Late in July, the two brightest stars of Orion the Hunter rise into view: reddish Betelgeuse with blue-white Rigel to its right. Between them lies the Hunter’s belt of three stars in a nearly vertical line. Orion will rise two hours earlier as each month passes.

The Astronomical Society of the Desert hosts monthly star parties at Sawmill Trailhead (elevation 4,000 feet). For dates, with map and directions to the site, visit the Society’s website at www.astrorx.org.

Sky’s the Limit Observatory in Twentynine Palms offers star parties most Saturday evenings, except when the moon is close to full. For details, visit www.skysthelimit29.org.

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. He remains active in research and public outreach in astronomy. Dr. Jeffrey L. Hunt, a retired planetarium director now living in the Chicago area, did the Venus map below. He has taught astronomy and sky watching to all ages. He studied astronomy education at Abrams Planetarium at Michigan State University. Jeff writes an astronomy blog at jeffreylhunt.wordpress.com and can be followed on Twitter at @jeff_hunt.

Now that the Earth has overtaken all the bright outer planets (with the final one being Saturn, reaching opposition on June 2), we can conveniently follow them at dusk for several months: Jupiter until start of September, Saturn until Thanksgiving, and Mars until end of May 2017.

Venus passes behind the sun on June 6, and by middle of July will emerge into our early evening sky very low in the bright west-northwest twilight glow shortly after sunset. Binoculars will help you spot Venus very low in twilight in its first weeks, and can reveal Mercury nearby from mid-July until late August. That’ll bring the total to all five bright planets visible simultaneously!

Our chart depicting the sky at evening mid-twilight follows positions of naked-eye planets and stars of first magnitude or brighter in the sky when the sun is 9 degrees below the horizon, roughly 45 minutes hour after sunset.

Jupiter starts high in the southwest in early June 2016, with faint Regulus, heart of Leo, preceding it as they move toward the western horizon.

Red Mars starts out unusually bright while low in southeast in early June, attracting attention to the triangle it forms with nearby Saturnand the red twinkling star Antares, heart of the Scorpion. The triangle crosses through south in late July-early August, and morphs into a spectacular, compact straight line in south-southwest on Aug. 24, as Mars passes directly between Saturn and Antares.

The Summer Triangle of Vega, Deneb and Altair rises in the eastern sky in June, ascending to nearly overhead in August. Two other bright stars, Arcturus and Spica, are highest in the southern sky in June, moving into west and west-southwest by the end of August.

With the unaided eye and binoculars, follow the motions of planets against the background stars. In mid-May, Mars passed closely north of a second-magnitude star, Delta Scorpii, the middle and brightest member of a nearly vertical slightly curved line of three stars in the head of Scorpius, to the west of Antares. Mars retrogrades, or goes westward, until ending nearly 10 degrees west of Delta Sco on June 29. Mars barely moves for several evenings, and then resumes eastward or direct motion, passing closely south of Delta Sco on Aug. 9.

Jupiter is moving eastward against the background. Note the first-magnitude stars Regulus in Leo, west of Jupiter, and Spica in Virgo, well to Jupiter’s east.

Follow the moon: Its day-to-day change in position against the stars, averaging 13 degrees per day, is much more noticeable than that of the planets. Watch the moon change from a thin crescent to just past full June 6-20, July 5-20 and Aug. 4-18, while passing the planets and the bright stars plotted on our evening twilight charts.

Jupiter’s dark equatorial cloud belts and up to four of the bright satellites discovered by Galileo offer a pleasing view for small telescopes. Even binoculars can show the moons; the best chances to see at least Callisto and Ganymede, the two outermost, come on June 11 and 12 (outermost Callisto and brightest Ganymede are both west, or to the lower right, of Jupiter); June 22 (both widely east, or to the upper left, of Jupiter) and June 29 (Callisto is widely west, Ganymede widely east). Using a medium-sized telescope with higher magnification, if atmospheric conditions are steady, try to see the Great Red Spot shortly after 9 p.m. on June 6, 18 and 30.

Mars, still showing a nice disk after its opposition and close approach of late May, displays surface detail! In June 2016, it is still late winter in Mars’ southern hemisphere—the southern spring equinox (or northern autumnal equinox) will occur on July 4. Although the south pole of Mars is then on the Martian terminator (day-night boundary), that pole is now tipped 15 degrees out of Earth’s view. Yet the surrounding southern polar cap of frozen carbon dioxide (or its overlying cloud cover) is near its maximum extent, reaching halfway from pole to equator, far enough to spill over the southern limb. So whenever you look at Mars early this summer, you’ll see a bright southern edge to Mars’ disk.

The most prominent dark marking on Mars, Syrtis Major, will be in fine position when it lies astride the pole-to-pole centerline of Mars at June 24 at 8:44 p.m.; June 25 at 9:21 p.m.; June 26 at 9:59 p.m.; June 27 at 10:36 p.m.; June 28 at 11:13 p.m.; June 29 at 11:51 p.m.; and on the night of June 30 (the morning of July 1) at 12:28 a.m. (Note these opportunities occur 37-38 minutes later each night, because Mars takes more than 24 hours to complete one rotation.) South of Syrtis Major lies Hellas Basin, the deepest crater on Mars. Its surface is often covered by clouds or frost, which would add to the bright area of the polar cap extending over the southern limb of Mars’ disk.

Enjoy Saturn’s rings this summer! They’re now tipped from edge-on by at almost the greatest angle possible. Using as high of a magnification as your telescope and atmospheric conditions allow (I often use 200x with my 6-inch reflector), try for the Cassini Division dividing the outer A ring from the broader, brighter B ring. This narrow gap is nearly two-thirds of the way from the inner edge of B toward the outer edge of A. Look also for Titan, Saturn’s largest moon, taking 16 days to complete one circuit around the planet. Its nearly circular orbit is almost nine times as large as the outer edge of Saturn’s A ring, in nearly the same plane as the rings, now tipped 26 degrees from edge-on, and so appears as an ellipse. Wherever Titan is in its orbit, it’s always about four ring diameters from the nearer ring edge, if you choose the diameter of the ring system passing through Saturn’s center and pointing toward and away from Titan.

Titan will appear farthest east of Saturn on June 9 and 25, and July 11, and farthest west on June 17, July 3 and July 19. We are seeing the north face of the rings and of Titan’s orbit, so we’ll see Titan at inferior conjunction (the near side of Saturn) passing south of the planet four days after greatest elongation east, and at superior conjunction (far side of Saturn) four days after it appears farthest to the west.

The Astronomical Society of the Desert hosts monthly star parties at Sawmill Trailhead (elevation 4,000 feet). For dates, with map and directions to the site, visit www.astrorx.org.

Sky’s the Limit Observatory in Twentynine Palms offers star parties most Saturday evenings, except when moon is close to full. For details, visit www.skysthelimit29.org.

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 and the planet-orbit 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.

Make necessary preparations to safely observe the transit of Mercury across the sun on May 9.

Jupiter is brightest “star” in evening sky this spring until Mars offers serious competition in late May, as the red planet presents its brightest and closest approach since 2005. The moon and Jupiter will pair up on May 14, while a “blue moon” and red Mars, at its brightest, team up on May 21.

On our chart depicting the sky at evening mid-twilight in May, we find two bright stars—Rigel south of west, and Aldebaran in the west-northwest—departing early in the month. The brightest star, Sirius, the Dog Star, is next to go, in the west-southwest. All that then remains of the Winter Hexagon will be the “Spring Arch” of Procyon, Pollux (with Castor 4.5 degrees to its right) and Capella. Orion’s shoulder Betelgeuse, below the arch, drops out by late May, soon after Sirius.

On the chart, bright Jupiter follows Regulus across the sky’s vertical north-south-overhead line, crossing it high in the south. Golden Arcturus climbs high in the east, while blue-white Spica is in the southeast, climbing toward the south. In the southeast, Mars first appears in evening mid-twilight around mid-month—and competes with Jupiter in brilliance—while Saturn and Antares follow about a week later. But you can see Mars, Saturn and Antares earlier in May, simply by observing later in the evening, or before dawn.

Low in the northeast in May’s evening twilight, bright blue-white Vega appears, followed by fainter Deneb to its lower left.

For illustrations of the following sky events in May, you are encouraged to download and reprint the free May 2016 Sky Calendar and evening sky map available at www.abramsplanetarium.org/skycalendar.

May 6: The new moon occurs at 12:30 p.m.

May 7: At dusk, look for the young crescent moon, age 31-32 hours, very low in the west-northwest. Aldebaran, eye of Taurus the Bull, is just to the moon’s upper left, beautiful in binoculars! On May 8, the moon will be higher, to the upper left of Aldebaran.

May 9: The transit of Mercury is visible from sunrise until 11:42 a.m.

If proper equipment is used, and precautions are taken to avoid eye damage, you will be able to observe Mercury in silhouette against the disk of the sun. During this transit, the tiny dot cannot be detected by simply looking through a solar filter without magnification. Instead, use a telescope suitably protected by a certified safe solar filter, securely installed at the front end of the telescope, before sunlight enters the optical system. Use a magnification of at least 50 power, or use your telescope to project an image of the sun on a screen or a piece of white cardboard. Whichever method is used, be sure to remove the finder scope so no one will be tempted to look through it at the sun.

From the Coachella Valley, the transit will already be under way at sunrise. The planet passes closest to the center of the solar disk at 7:58:31 a.m., with the sun 25 degrees up in the east. At 11:39:06 a.m., the leading edge of Mercury will meet the edge of the sun. Egress lasts 3.2 minutes, until 11:42:18 a.m., when Mercury moves completely off the solar disk.

May 10, 11: From one evening to the next, the moon leaps over the line joining Pollux and Procyon.

May 13: The moon, just past first quarter phase, is in the afternoon and evening sky. Note Regulus, heart of Leo, above the moon.

May 14: Using binoculars a few minutes before sunset, can you spot Jupiter not far to the upper left of the moon. Also: This is Astronomy Day! You’re welcome to attend our star party that evening; details below.

May 15-21: Mars, going west one-third of a degree daily against background stars, passes closely north of Delta, brightest and middle star of three in the head of Scorpius. Two hours after sunset, Mars is the brilliant reddish object low in the southeast.

May 17, 18: The bright star near the moon is Spica, in Virgo.

May 21: The full “blue moon” and red Mars hang out together from dusk until dawn. In spring 2016, we have four full moons: On March 23, April 21, May 21 and June 20. The third full moon of four within the same astronomical season is called a “blue moon.” Also tonight: Mars is at opposition—as Earth overtakes Mars, we observe the red planet all night long, from dusk to dawn, in the direction opposite to the sun.

Today’s “blue moon” rises in the east-southeast around sunset, with Mars quickly becoming visible 6 to 7 degrees to the moon’s right. Within two hours after sunset, below the moon and Mars, look for Saturn with the twinkling red first-magnitude star Antares, “Rival of Mars,” about 7.5 degrees to Saturn’s right. For the rest of the night, these four bright objects form a striking quadrilateral, in clockwise order: moon, Mars, Antares and Saturn.

Also that night: Syrtis Major, the most prominent of the dark markings on Mars, lies near the center of the Martian disk as the planet reaches its highest position in our southern sky, when telescopic viewing is best. This feature was discovered by Dutch astronomer Christiaan Huygens, who included it on a drawing of Mars in 1659. He used repeated observations of the feature to estimate the length of a day on Mars. Because Mars’ day is slightly longer than Earth’s, around opposition, we see the same face of Mars about 36 minutes later on each successive night.

If you’re inclined to observe the predawn sky at this time of year, despite the early sunrises, you’ll find the triangle of Mars, Saturn and Antares sinking into the southwest; Arcturus in the west to west-northwest; the Summer Triangle of Vega, Altair and Deneb overhead; and Fomalhaut low in the southeast.

Star Parties

On Saturday, May 14, from 8 to 10 p.m., the Astronomical Society of the Desert will be hosting the last star party of the season at the Visitor Center of the Santa Rosa and San Jacinto Mountains National Monument, on Highway 74, within four miles south of Highway 111 in Palm Desert. The society’s website at www.astrorx.org has directions and a map to our year-round high-altitude star parties at Sawmill Trailhead. Also check the separate link to our “Impromptu Star Parties,” which could be announced on short notice at any time.

Robert C. Victor was 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 and the planet orbit 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.

Jupiter and Sirius—until it departs—continue to dominate the evening sky in April. This year’s best evening appearance of Mercury in mid-April precedes its transit across the Sun on May 9. Meanwhile, Mars brightens on its way to next month’s closest approach since 2005. The Mars-Saturn-Antares triangle, prominent in morning, can also be seen rising very late in evening. Don’t miss this spring’s offerings to get close-up telescopic views of some planets!

First, some dates to keep in mind.

April 7: The new moon occurs at 4:24 a.m., and the moon at perigee at 11 a.m. Large tides!

April 8: The young crescent Moon, age 39 hours, is easy to see in twilight. Look for Mercury to the moon’s lower right.

April 10: The moon occults Aldebaran in daytime; look at it with a telescope. In the evening, find this star and the Hyades cluster closely to the lower right of the moon, a spectacular sight for binoculars!

April 12: Spica is at opposition, visible all night.

April 13: The moon is at first quarter, half-full in the afternoon and evening sky. Today and for a day or two before and after, install a single polarizing filter in your telescope’s low-power eyepiece, and rotate the eyepiece to darken the sky and improve the contrast of moon against the blue daytime sky.

April 16-23: Before dawn, Mars and Saturn reach their minimum distance apart, 7.2 degrees. Stopping short a few degrees north-northwest of Antares, Mars begins to retrograde on April 17. The red planet will move nearly 16 degrees west by June 29.

April 17: The moon is near bright Jupiter at dusk. On April 17 and 18, Mercury stands near greatest elongation, reaching its greatest altitude at dusk for 2016, but it begins to fade rapidly later this week.

April 20, 21: The moon is near Spica most of night. The full moon occurs on April 21 at 10:24 p.m.

April 24, 25: Four hours after sunset until dawn, view a spectacular gathering of the moon, Mars, Saturn and Antares.

In mid-April at dusk, Jupiter shines bright and steady well up in southeast, while next in brilliance, the blue-white “Dog Star” Sirius twinkles in the southwest. Catch Mercury before it reaches its high point low in the west-northwest April 17 and 18; it will still outshine golden Arcturus in the east-northeast to east This innermost planet of our solar system passes greatest elongation on those dates, when it appears farthest from the sun, 20 degrees this time around.

Mercury will get farther from the sun on other occasions this year, but this time, the planet is almost directly above the sun, which is 9 degrees below the horizon at the time of our evening chart/ This arrangement results in the best apparition of Mercury in the evening sky of this year. But don’t wait! As it circles the sun and comes around to the near side of its orbit, Mercury shows less of its sunlit side. Moreover, features large and small on its rough, rocky surface cast shadows, causing the planet to fade rapidly after greatest elongation. Mercury shines at magnitude -1 on April 7-8 and magnitude 0 on April 17, before fading to +1 on April 22-23, and +2 on April 27.

If proper equipment is used and precautions taken to avoid eye damage, you will be able to observe Mercury in silhouette against the disk of the Sun on Monday morning, May 9. More on this transit next month.

After Mercury fades away into the bright western twilight in late April, there are still several bright stars remaining in the western sky. Each evening within an hour after sunset, keep track of the stars Rigel, Aldebaran, Sirius, and Betelgeuse. By late in May, they’ll all be gone.

In April and early May, you can stay up late into the evening to view the pretty triangle of Mars-Saturn-Antares. On the night of April 24, four hours after sunset, see this triangle below and lower right of the waning gibbous moon, while Jupiter shines high in the southwest. On April 25, at the same late hour, you’ll find the moon low in the east-southeast, to the lower left of the triangle.

Jupiter, with its cloud belts and four bright moons discovered by Galileo, and Saturn, with its rings, are impressive showpieces for even small telescopes!

But Mars is usually not all that impressive, except within a couple of months of its oppositions, when you can get glimpses of surface features. At this year’s opposition, Mars is low in the sky, so it is best viewed when it is highest, as it passes due south. In mid-April, that happens around 3:30 a.m. Next month, we’ll have more on observing Mars, its surface features, rotation and seasonal changes.

As for events this month: The Whitewater Preserve will be hosting a star party on Saturday, April 2, from 7:30 to 10 p.m. Reservations required; call (760) 325-7222.

The Astronomical Society of the Desert will be hosting its popular monthly star party on Saturday, April 16, from 8-10 p.m., 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. Check the society’s website at www.astrorx.org for listings of our next lecture meeting—Dennis Mammana on “Capturing the Cosmos” (sky photography)—at 7 p.m. on Friday, April 8; and our next high altitude star parties at Sawmill Trailhead starting at dusk on April 2 and April 30. Check the separate link to our “Impromptu Star Parties,” which could be announced on short notice at any time.

From early March through early June 2016, the Earth will overtake all three bright outer planets within just 87 days, with each planet reaching peak brilliance and all-night visibility: Jupiter in early March; Mars in late May; and Saturn in early June.

For several months following these oppositions, each respective planet will remain conveniently visible in the evening sky … at last!

What does opposition mean? When at opposition as seen from Earth, a planet appears at or nearly 180 degrees from the sun, and appears on the opposite side of the sky from where the sun is located. Thus, the planet will be up all night: low in the eastern sky at dusk, high in the south in the middle of the night, and low in the western sky at dawn. Near the date of its opposition, a planet reaches its closest approach to Earth, and its peak in brilliance.

For several weeks through late February, early risers enjoyed a wide panorama of all five naked-eye planets across the morning sky. Nine folks joined us for our viewing on Feb. 7 to revel in views of five planets, Jupiter’s moons and Saturn’s rings, and a rising old crescent moon just 24 1/2 hours before new. Thanks for coming out!

We’re now starting to offer informal Impromptu Sky Watches or Neighborhood Mini Star Parties. Most will occur in the evening. Check this story for some listings. Hope to see you there!

Mornings in early March: If the mountains don’t block your view, it’s still possible to catch Venus low in the east-southeast, and Jupiter low in the west simultaneously, while Saturn, with brighter reddish Mars nearby to its right, adorns the southern sky. Between Mars-Saturn and a little lower, look for the reddish star Antares, heart of the Scorpion. The light of Antares is more noticeably affected by Earth’s atmosphere, causing it (and other stars) to twinkle.

In the mornings as March progresses, Venus and Jupiter sink toward opposite horizons, with Venus heading toward its June 6 superior conjunction on the far side of the sun, and Jupiter reaching opposition to the sun on the morning of March 8 as Earth overtakes it. That morning, with Jupiter in the west, the sun below the eastern horizon, and Saturn in the south just more than 90 degrees west of the sun, we can visualize our counterclockwise revolution around the sun and the forward motion of our Spaceship Earth toward Saturn. Venus, moving faster, is leaving us behind, and we are passing Jupiter, causing it to drop from sight in our right (west) window.

March evenings: Theyare rich with bright stars and planets. Jupiter, rising in the east, is the first of several planets to grace the sky at dusk in coming months. Dog-walkers and others out and about regularly at dusk will be rewarded with many striking astronomical sights this spring. At dusk on March 7 (early during the night of Jupiter’s opposition), we have the sun below our western horizon, and Jupiter visible in the east. Now we’re looking out the rear window of Spaceship Earth. On March 7, we’re moving away from a point in Taurus, about 8 degrees east-northeast of Aldebaran. Faster-moving Mercury will emerge from beyond the sun and have the year’s most favorable evening apparition in the western sky at dusk in April, before it transits the sun on May 9.

Our charts depict the sky at mid-twilight, which we define as the moment when the sun is 9 degrees below the horizon. During March, in the Coachella Valley, mid-twilight occurs about 40 minutes before sunrise (effectively concluding your sky watch, as stars and planets fade in the brightening dawn), or 40 minutes after sunset (a fine time to start your evening viewing, as stars and planets become easier to find in the fading light of dusk).

Sky events in morning twilight

March 1: The moon, just more than half full in the south, is approaching last-quarter phase. Mars is 9 degrees to the lower right. Saturn is 9 degrees to the lower left, with Antares 9 degrees below the moon and nearly 9 degrees to the lower right of Saturn.

March 2: The moon is 4-5 degrees to the upper left of Saturn.

March 3: Venus and Jupiter are 150 degrees apart.

March 7: The old moon, about 1.5 days before new, is visible near Venus for the last time in the planet’s morning apparition; Look 4 degrees to the left of Venus.

March 8: Jupiter is at opposition! Spaceship Earth now overtakes the giant planet. We are heading about 2 degrees left of Saturn. As we follow our curved orbit around the sun, we will overtake Mars on night of May 21-22, and Saturn on night of June 2-3.

March 9: Mars and Saturn are 15 degrees apart.

March 23: Before Jupiter sets, the three bright outer planets, in order from west to east—Jupiter, Mars and Saturn—span 90 degrees.

March 27: Mars and Saturn are 10 degrees apart. They’ll be separated by no more than 10 degrees through May 12, and will be as close as 7.2 degrees apart April 16-23.

Sky events in evening twilight

March 7: Jupiter is at opposition tonight as Spaceship Earth overtakes it. We are now moving away from a point in Taurus about 8 degrees east of Aldebaran.

March 9: The first waxing crescent moon, age 24-25 hours is low, 3-4 degrees south of west.

March 13: The moon is below the Hyades star cluster and Aldebaran at dusk.

March 14: The moon is east of Aldebaran at dusk.

March 15: The moon is north of Betelgeuse at dusk.

March 17: The moon is east of the Pollux-Procyon line at dusk.

March 19: The moon is to the upper right of Regulus at dusk. Spring begins at 9:30 p.m.! A Star Party is hosted by Astronomical Society of the Desert; www.astrorx.org

March 20: The moon is to the lower right of Regulus at dusk.

March 21: The moon is 2 degrees south of Jupiter, now 165 degrees from the sun, at dusk. Note the moon’s phase as it passes Jupiter in the evening sky every 27-28 days this spring and summer, until the last pairing, with a thin crescent moon, on Sept. 2.

March 23: Mercury is at superior conjunction, hidden on the far side of the sun. In 7-10 days, using binoculars half an hour after sunset, try to find it very low in the bright twilight glow, north of west. In first three weeks of April, Mercury will be easy to find with the unaided eye.

Resources

A YouTube video showing a view of the morning twilight sky from mid-October 2015 until early March 2016, followed by a view of the evening twilight sky from early March through late October 2016, is available here.

Illustrations of aforementioned events appear in the Sky Calendar. For a sample issue and subscription information, visit www.abramsplanetarium.org/skycalendar.

The Astronomical Society of the Desert will host a star party on Saturday, March 19, from 7-10 p.m., at the Visitor Center of the Santa Rosa and San Jacinto Mountains National Monument. Get info on future star parties, with directions and maps to the two sites, as well as news on lectures and special events, at www.astrorx.org

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 and the planet orbit 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.

Join us for Impromptu Sky Watches, or Neighborhood Mini-Star Parties, to be held in a neighborhood, park or at a school by one or more members of the Astronomical Society of the Desert!

The purpose is to observe a fairly unusual but eye-pleasing astronomical event we’d like to share with others. The event might be a very thin crescent moon in morning or evening twilight, or it could be a rare gathering of celestial bodies. A close pair of planets, or a planet and a star, or the moon and a planet or bright star, may trigger our desire to share the experience of viewing the event. Sometimes, a sky watch might be arranged to see a very favorable pass of the International Space Station across our local skies, or just to enjoy a moonrise over our scenic mountain horizon.

If you’d like to join us for one or more of these Impromptu Sky Watches, or if you want to observe the event on your own, visit astrorx.org for more information. Of course, the Sky Watch would be cancelled if clouds interfere. We’ll often wait until just a few days before the event to make an announcement, to obtain a more accurate forecast of whether the sky is likely to be clear.

The locations of Sky Watches will be:

1: In Palm Springs, on the sidewalk along the east side of Farrell Drive, within 300 feet north of the golf-cart crossing just north of Mesquite Avenue. We’ll be overlooking the golf course on both sides of Farrell Drive.

2: In Palm Springs, on the pedestrian bridge crossing over Tahquitz Creek, at Camino Real between north and south Riverside drives, three blocks north of Cahuilla Elementary School.

3: In Desert Hot Springs. The exact location has not yet determined, and will be announced at astrorx.org. Desert Hot Springs, and other places far east in the Coachella Valley where high mountains don’t obstruct the view of the western horizon, are better places for viewing phenomena low in the west, such as a young crescent moon or evening appearances of the planet Mercury.

Moonrise Watches: Join us, if the sky is clear, by arriving at location No. 2 in time for moonrise at the following dates and times:

Monday, Feb. 22 at 5:51 p.m. (just past full)

Tuesday, Feb. 23 at 6:46 p.m.

Wednesday, Feb. 24 at 7:40 p.m.

Old moon watch, on the last two mornings to see the thin old crescent moon in this lunar cycle: On Sunday, March 6, and Monday March 7, during 5:10-5:40 a.m., we’ll be at site No. 2 to watch for the rising of Venus and the crescent moon. On Saturday, Venus will be 10-11 degrees to the lower left of the moon. On Sunday, look for Venus 4 degrees to the right of the old moon, just over 1.5 days before new. This is the last easy chance to view the moon and Venus close together during Venus’ current morning appearance, which began late in August 2015.

Young moon watch, on the first evening to see the thin young moon of the new lunar cycle: On Wednesday, March 9, arrive to site No. 3 at 6:10 p.m. to catch the young crescent moon only 8 degrees up, just south of due west, while Jupiter, almost in the opposite direction in the sky from the sun, is 7 degrees up in east. The moon will be just more than 24 hours old.

Moon near two star clusters in Taurus: On Sunday, March 13, join us at site No. 2 at 7:45 p.m. to enjoy views of the Pleiades and Hyades star clusters, and the star Aldebaran, eye of Taurus, the Bull, near the fat crescent moon.

Moon near Jupiter: On Monday, March 21, sunset occurs at 6:59 p.m. On your own, using binoculars, can you spot Jupiter to the moon’s upper left before then? You’re welcome to join us at site No. 2 at 8 p.m. for views of this pairing of Moon and our solar system’s largest planet, and of stars of winter and early spring.

Moonrise watches: Join us, if the sky is clear, by arriving at site No. 2 in time for moonrise at the following dates and times:

Wednesday, March 23, at 7:26 p.m. (just past full)

Thursday, March 24, at 8:19 p.m.

Friday, March 25, at 9:12 p.m.

Young crescent moon and Mercury: Join us on Friday, Apr. 8 at site No. 3 by 7:45 p.m. As the sky darkens, we’ll enjoy a wonderful view of a young crescent moon an easy 39 hours old, with earthshine on its non-sunlit side, and Mercury shining within 9 degrees to its lower right. Jupiter will gleam well up in the east-southeast.

Moon and Aldebaran: For those who’d like to try to witness this daytime event on their own with a telescope, watch Aldebaran get covered by the dark side of the moon on Sunday afternoon, April 10, at 2:24 p.m., and reappear at the moon’s sunlit edge at 3:46 p.m. If you’d like to join us at site No. 2 at 8:15 p.m., we’ll check how far the moon has crept away from the star, and we’ll tour the April evening sky.

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.