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Last updateTue, 18 Sep 2018 1pm

Evenings this month feature the gas-giant planets, Jupiter and Saturn, and on dark moonless nights, the Milky Way. Predawn skies include the bright stars we’ll meet again on winter evenings—and a brief visit by our solar system’s smallest planet, Mercury.

In the evening, bright Jupiter gleams in the south to south-southwest at dusk, while Saturn is in the southeast to south-southeast, 31 to 29 degrees east (to the left) of Jupiter. Note Antares, heart of Scorpius, twinkling to Jupiter’s lower right. Jupiter lingers 7 degrees from this red supergiant star from mid-July through first week of September; their least separation of 6.7 degrees occurs Aug. 8-15 as Jupiter ends retrograde on Aug. 11.

Follow the moon at dusk Aug. 2-15. On Aug. 2, the thin crescent moon is easy to see, though very low, a little north of due west. Don’t miss a striking pairing of the moon and Jupiter, within 3 degrees, at dusk on Aug. 9, and the moon and Saturn, just 3 degrees apart on Aug. 11. By the evening of Aug. 12, the moon has moved 9 degrees east of Saturn. On Aug. 15, the moon, past full, is rising in the east-southeast. The moon returns to the evening sky as a crescent low in the west on Aug. 31.

The year’s best Milky Way viewing after evening twilight occurs through Aug. 2, and Aug. 20-Sept. 1. Go to a dark place to enjoy these with the unaided eye and binoculars: the Cygnus Star Cloud, along axis of the Northern Cross or neck of the Swan, within the Summer Triangle; the Great Sagittarius Star Cloud, above the spout of the Teapot; the Great Rift, a dark lane of dust dividing the Milky Way into two streams southward from Cygnus; Lagoon Nebula M8 (Messier 8), above the tip of the spout; star clusters M7 and M6, near the end of the tail of Scorpius; and much more.

As for the mornings: Mercury makes a brief visit to the a.m. sky. It brightens past first magnitude (to +0.9) by Aug. 5 to become visible low in the east-northeast morning twilight. During Aug. 5-10, it lingers 9 degrees to the lower right of Pollux while brightening another magnitude to -0.1. Mercury reaches greatest elongation, 19 degrees west of the sun, on Aug. 10, and on Aug. 11, a line from Castor to Pollux, 4.5 degrees apart, extended nearly 10 degrees, locates Mercury. Late in the month, Mercury sinks into bright twilight; superior conjunction beyond the sun will occur Sept. 3. The “Dog Star” Sirius, the brightest star, emerges in the east-southeast morning twilight before mid-August. Sirius rises 4 minutes earlier each morning, climbing higher as the month progresses. Note Orion’s belt points almost directly to Sirius.

Follow the moon in morning sky Aug. 15-29: On Aug. 15, the moon is full, setting in the west-southwest. The moon passes last quarter phase on Aug. 23, while 9 degrees south of Pleiades. On Aug. 24, the fat crescent moon is 2 degrees north of Aldebaran, eye of the Bull. On Sunday, Aug. 25, the 30 percent crescent moon occults third-magnitude Zeta Tauri, tip of southern horn of Taurus. From the Coachella Valley, the star disappears behind the bright edge of the moon at 3:46 a.m., and reappears from behind the dark, earthlit side at 4:41 a.m. It’s best viewed with a telescope.

Absent in August are Venus, in superior conjunction on night of Aug. 13, and Mars, in conjunction on Sept. 2. When passing beyond the sun, Venus and Mars remain out of sight for longer than other planets, because their motions most closely match that of Earth; Venus is the next planet inward from Earth, and Mars is the next planet beyond Earth’s orbit. Venus goes faster than Earth and so emerges from beyond the sun into the evening sky. Mars goes more slowly and emerges into the morning sky. During the 2019-20 school year, each participates in a spectacular gathering: Venus, with Jupiter and Saturn at dusk in late November-early December; and Mars, with Jupiter and Saturn at dawn in late March 2020. Stay tuned!

Abrams Planetarium publishes a monthly Sky Calendar with an evening sky map. The calendar illustrates many of the present and future events described here. Subscriptions are $12 per year at www.abramsplanetarium.org/skycalendar for three printed issues, mailed quarterly.

For a preview of evening and morning planet viewing through August 2020, see Jeffrey Hunt’s two-page graphic summary of moon and planet setting and rising times, relative to the times of sunset and sunrise, exact for Palm Springs, below. The graph of evening planet setting times shows the departure of Jupiter and Saturn in December 2019, and Venus improving until its very favorable evening appearance in March 2020, when it will set 3 1/2 hours after sunset, followed by its rapid departure from the evening sky in May. The graph of morning-planet-rising times shows the gradual emergence of Mars before dawn in autumn 2019; the emergence of Jupiter and Saturn in January-February 2020; and the sudden rise of Venus into predawn prominence in June-July 2020. The charts also make it easy to pick out the best dates to see Mercury in evening and morning skies.

Check the website of the Astronomical Society of the Desert at www.astrorx.org for dates and times of our evening star parties. Sawmill Trailhead, our high-altitude site (elevation 4,000 feet—wear warm clothes), will have its next monthly sessions starting at dusk on Saturdays, Aug. 31 and Sept. 28. Our primary, more-accessible location is 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). Monthly sessions there will resume on Saturday, Oct. 5.

But don’t wait until then! You can pre-register for one of the Stargazing Parties offered several times each month at the Rancho Mirage Library Observatory at www.ranchomiragelibrary.org/observatory.html. (Click on Stargazing Parties, then sign up for their eNewsletter to receive registration information.) If you go farther afield, check out the Sky’s the Limit Observatory and Nature Center in Twentynine Palms, at www.skysthelimit29.org.

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.

Published in Astronomy

June evenings will be wonderful for viewing the skies, especially if you stay up late enough until the sky fully darkens. With daylight saving time in effect on these longest days of the year, that might be a tall order!

Mercury starts 16 degrees to the lower right of Mars on June 1, climbing to 0.3 degrees above Mars on June 18, at their closest pairing. Mercury and Mars remain within 3 degrees June 14-24. Mercury decreases in brightness, from magnitude -1.0 on June 1, through 0.0 on June 16, to +1.0 on June 30. Mercury fades rapidly in first days of July, but in June, it remains much brighter than Mars’ magnitude +1.8—as faint as Mars ever gets.

Elsewhere in the west to northwest, Procyon and Capella drop out of sight, but the Gemini Twins, Pollux and Castor, 4.5 degrees apart, hold on. During June 18-21, first Mercury, then Mars, pass 5.5 degrees south (to the lower left) of Pollux for two nights each, while the Mercury-Mars pair widens from 0.3 to 1.8 degrees apart. Mercury is the brightest member of this gathering of two planets and two stars.

In June, Regulus slides down the western sky on its way to its conjunction with the sun on Aug. 23. Spica and Arcturus pass their highest positions in the south. Golden Arcturus, at magnitude -0.1, is the brightest star on June evenings, but the planet Jupiter, at magnitude -2.6 in the southeast, appears 10 times brighter. Note red, twinkling Antares within 12 degrees to Jupiter’s upper right on June 1, and within 9 degrees to its right at dusk on June 30. Jupiter is at opposition to the sun on June 10, and is retrograding, or appearing to move westward against the background stars.

By mid-June, Altair rises north of east to complete the Summer Triangle with Vega and Deneb, just in time for the new season. Summer begins at 8:54 a.m. on June 21, with the sun directly over the Tropic of Cancer. The highest sun of the year, only 10 degrees south of overhead for Palm Springs, occurs that day at 12:48 p.m.

Saturn rises in time for mid-twilight in the last days of June. Watch for it in the east-southeast, 31 degrees to the lower left of Jupiter. Saturn’s opposition will occur on July 9.

On the morning twilight chart below, you’ll find the stars, but not fast-moving Venus, in roughly the same positions they’ll occupy in evening twilight in November. On June mornings (and November evenings), the Summer Triangle moves west of overhead. Bright Jupiter, with Saturn to its upper left, will be sinking into the southwest. Fomalhaut, Mouth of the Southern Fish, will be low in the south-southeast to south. Capella, the “Mother Goat” star, will be rising in the northeast. Aldebaran, eye of Taurus, rises in the east-northeast late in month. By getting up before dawn, you’ll get a preview of the evening sky of the next season!

Alignments: On May 31, Earth and Aldebaran are on opposite sides of the sun. As seen from Earth, Aldebaran appears in conjunction with the sun, hidden from our view until it emerges in the east-northeast morning twilight in late June. Also on May 31, Earth passes between Antares and the sun, and that star appears at opposition to the sun, visible almost all night.

On June 10, Jupiter will be at opposition, 180 degrees from the sun and visible all night. Jupiter that night is low in the southeast at dusk, and reaches its highest in the south in the middle of the night, and is low in the southwest at dawn. On July 9, Saturn will be at opposition.

For nearly all of June, Mercury has a favorable evening appearance, including a close approach to Mars for several evenings around June 18. In morning twilight on June 1, Venus is very low in the east-northeast, with the old moon nearby. Jupiter is low in the southwest, 150 degrees from Venus, while Saturn is 29 degrees to Jupiter’s upper left. On July 1, the old moon is again near Venus, but Jupiter has already set. Instead, Saturn will be low in the southwest nearly 160 degrees from Venus. In June, the gap between Venus and these giants widens toward 180 degrees, at mutual oppositions reached by Venus-Jupiter on June 23, and Venus-Saturn on July 17.

There are evening pairs of planets at mutual opposition: Mercury (setting) and Jupiter (rising) on May 30; Mars (setting) and Saturn (rising) on June 14; and Mercury (setting) and Saturn (rising) on June 16. Jean Meeus, in his Mathematical Astronomy Morsels IV, wrote about planets in mutual opposition: “Certainly this is a matter of almost zero observational interest. Somebody who likes to observe weird things might be interested in the near-simultaneous rise/set of two planets in opposition, but it’s far from the mainstream.”

Mercury, Mars and the Twins of Gemini: These four objects are visible in the west-northwest at dusk throughout June, but Mercury is very low at start of month, and all are low in the closing days. I already mentioned Mercury’s fading brightness and Mars’ relative faintness. Watch these changing arrangements of Mercury and Mars with Pollux and Castor, the “Twin” stars of Gemini, 4.5 degrees apart. Binoculars enhance the view, especially late in month, when all will be low in bright twilight. June 5: Mars forms an isosceles triangle with Pollux-Castor, 11 degrees from each. June 12: Mercury forms an isosceles triangle with Pollux-Castor, 10-11 degrees from each. June 18: Mercury-Mars appear closest, 0.3 degrees apart, within 6 degrees to the lower left of Pollux. June 18 and 19: Mercury is 5.5 degrees south (to the lower left) of Pollux. June 20 and 21: Mars is 5.5 degrees south of Pollux. June 25: A line from Castor to Pollux, extended 8.7 degrees, locates Mercury. (The three objects appear to be in a straight line.) June 28: A line from Castor to Pollux, extended 7.2 degrees, locates Mars.

The moon on June evenings: On June 4 at dusk, look low in the west-northwest for the young crescent moon with earthshine, with bright Mercury 7 degrees to the lower right, and faint Mars 7 degrees to the upper left. Jupiter rises about one hour before Mercury sets. Try to view Mercury, Mars and Jupiter simultaneously, within an hour after sunset. On June 5, find Mars 7 degrees to the moon’s lower right, and Pollux 8 degrees to moon’s upper right. On June 6, use binoculars to find the Beehive Cluster within 3 degrees to moon’s upper left after nightfall. Find Regulus near the moon on June 8. The moon passes first quarter phase on June 9. Spica is fairly near the moon on June 11 and 12. From June 12 and for the rest of Mercury’s evening apparition, Mercury and Mars are no more than 4 degrees apart. On June 14 at dusk, find Antares 14 degrees to the moon’s lower left. On June 15, find bright Jupiter 8 degrees to the moon’s lower left, and Antares 7 degrees to moon’s lower right. On evening of June 16, the moon is 6 degrees to the lower left of Jupiter. The full moon later that night, at 1:31 a.m. on June 17, is the fourth during spring 2019. On the evening of June 17, the moon, past full, rises 18 degrees lower left of Jupiter.

Follow the moon in morning sky through the latter half of June. On the 16th, the moon, not quite full, sets in the west-southwest shortly before sunrise, 5 degrees to the lower right of Jupiter. On the next morning, June 17, the full moon appears 8 degrees to the upper left of Jupiter and 22 degrees to the lower right of Saturn. On June 18, the moon will have moved more than two-thirds of the way from Jupiter toward Saturn, and on June 19, the moon will appear 4 degrees to the upper left of Saturn. On June 25, the moon will reach last quarter phase, half full in the morning sky. On June 29, a beautiful crescent moon with earthshine will appear low, north of east, accompanied by the Pleiades cluster, 10 degrees to the upper left, and bright Aldebaran, eye of Taurus, 15 degrees to the lower left. On the 30th, a thinner crescent moon will appear with Aldebaran within 2 degrees below.

Abrams Planetarium publishes a monthly Sky Calendar with an evening sky map. The calendar illustrates many of the events described in this article. Subscriptions are $12 per year at www.abramsplanetarium.org/skycalendar for three printed issues mailed quarterly.

Check the website of the Astronomical Society of the Desert at www.astrorx.org for dates and times of our evening star parties.Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have its next monthly session starting at dusk on Saturday, June 1.

Wishing you clear skies!

Robert 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 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.

Published in Astronomy

A thin crescent moon low in the west-northwest at dusk on May 5 marks the start of Ramadan, with a month-long daytime fast beginning the next day. Nearly two weeks later, a “blue moon”—the third of four full moons within the season—is visible through all nighttime hours of May 18. Late in the month, bright Jupiter begins rising in southeast during early evening hours.

The May evening twilight chart shows that Rigel, Aldebaran, Sirius and Betelgeuse disappear this month, leaving four winter stars—Procyon, Pollux, Castor and Capella—forming an arch in the western sky through month’s end, when Mercury is just starting an evening appearance very low in the west-northwest.

Regulus in Leo crosses high in the south into the west-southwest. Golden zero-magnitude Arcturus rises high in the eastern sky, with blue-white first-magnitude Spica in Virgo to its lower right. Zero-magnitude Vega, the brightest member of the Summer Triangle and first to appear, rises into view in the northeast, with Deneb eventually trailing to its lower left. Red Antares, heart of Scorpius, rises in the southeast late in May. Bright Jupiter follows 12 degrees to Antares’ lower left, just in time for the end of May.

Nearly all the events described here are illustrated on the Abrams Planetarium Sky Calendar. Subscriptions are $12 per year at www.abramsplanetarium.org/skycalendar for three printed issues, mailed quarterly. A free, printable copy of the May 2019 issue is available at the site.

May 2 at dawn: The old moon is very low in the east, 4 degrees to the lower right of Venus.

Sunday, May 5, at dusk: The sighting of the young crescent moon low in the west-northwest, perhaps by half an hour after sunset, marks the start of Ramadan.

On May 6 at dusk: Look for the crescent moon with earthshine 3 degrees to the upper right of Aldebaran. Follow the moon nightly at dusk through May 18, watching it pass Mars on May 7, Pollux on May 9, the Beehive on May 10 (use binoculars), Regulus on May 11 and 12, and Spica on May 15.

On May 18 at dawn: The moon, some 8-9 hours before full, is low in the west-southwest. Today’s full moon is the third of four within the same season, spring 2019, so by one definition (Maine Farmers’ Almanac, 1937), it is called a “blue moon.” This definition predated the now widespread use of the term “blue moon” to refer to the second full moon within a single calendar month.

At dusk on May 18: Some 5-6 hours after full, the moon is very low in the east-southeast. From the Coachella Valley on May 18, the moon sets in the west-southwest about 5 minutes after sunrise, and rises in the east-southeast about a minute after sunset, but unless you’re at a site higher than your surroundings, it will not be possible to view the sun and moon simultaneously.

Two hours after sunset on May 18: Find Antares 11 degrees below the full moon; on May 19, find Jupiter 7 degrees to the moon’s lower left; and on May 20, see the moon rising 6 degrees to the lower left of Jupiter. Rather than stay up late, you can switch to mornings to catch the waning gibbous moon passing Antares, Jupiter and Saturn May 19-23. The last quarter occurs May 26. Finally, catch the last old crescent near Venus on June 1.

(Almost) opposing planets: On May 20, Jupiter rises about one hour before Mars sets. About two hours after sunset, both planets are about 5 degrees above opposite horizons. It’ll get easier to view both planets simultaneously in coming weeks, as Jupiter rises earlier.

Mars fades from magnitude +1.6 to +1.8 in the west-northwest at dusk. Watch Mars pass between Beta and Zeta Tauri, tips of Bull’s horns, on May 6. Crossing into Gemini on May 16, Mars goes 2 degrees north of Eta and Mu, third-magnitude stars 1.9 degrees apart in Castor’s foot, May 21-24. On May 31, Mars is 0.9 degrees south of third-magnitude Epsilon Gem.

Late evening until dawn: Bright Jupiter, in Ophiuchus, on May 1 rises within 15 degrees to the lower left of Antares, three hours and 10 minutes after sunset, as Mars sets. Saturn in Sagittarius rises within two hours later. Jupiter rises half an hour earlier each week, and by May 31 rises 12 degrees to the lower left of Antares 40 minutes after sunset, with Saturn still following by two hours. Jupiter (magnitude -2.5 to -2.6) and Saturn (+0.5 to +0.3) brighten slowly and stay 27-29 degrees apart, as both retrograde, by 3.0 degrees and 0.8 degrees, respectively. Jupiter passes 2.5 degrees north of 3.3-magnitude Theta Oph May 23-24.

On May 24, best in the darkness hours before dawn: Jupiter, moving retrograde, or westward against the stars, passes 2.5 degrees north of the 3.3-magnitude star Theta in Ophiuchus. Jupiter passed that star while going eastward on Feb. 27.

In the morning twilight, find bright Jupiter in the south-southwest to southwest, getting lower as the month progresses, with red Antares, heart of Scorpius, 15 to 12 degrees to its lower right; and Saturn, passing through the south during May; and Venus, very low in the east to east-northeast in brightening twilight. Binoculars may show Mercury to the lower left of Venus for the first few days. The morning twilight chart below shows all that, plus the Summer Triangle of Vega, Altair and Deneb passing overhead; golden Arcturus sinking in the west to west-northwest; and Fomalhaut, Mouth of the Southern Fish, low in the southeast.

Check the website of the Astronomical Society of the Desert at www.astrorx.org for dates and times of our evening star parties. Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have sessions starting at dusk on Saturdays, May 4 and June 1. Our primary, more-accessible location is 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). Our final one for the season will be on Saturday, May 11, from 8 to 10 p.m.

Also, remember to check the Impromptu Star Parties link on the Astronomical Society’s webpage. I’ll be offering a Ramadan Young Moon Watch on Sunday, May 5, at a yet-to-be-selected site with a view toward the west-northwest horizon, and other sky watches in Palm Springs at the pedestrian bridge over Tahquitz Creek at North Riverside Drive and Camino Real.

Wishing you clear skies!

Robert 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 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.

Published in Astronomy

My lifelong interest in sky-watching began in the school year 1951-52, a year after our sixth-grade teacher led us to create a mural of the solar system, with the planet sizes to scale.

When I was in seventh-grade, our school library included two books which really changed my life: A Dipper Full of Stars, by Lou Williams Page, originally published by in 1944—and revised and republished as a California state textbook in 1959! The other book was The Friendly Stars, by Martha Evans Martin, published in 1907.

On the first page of A Dipper Full of Stars is a quote from Harlan T. Stetson’s Man and the Stars: To acquire some appreciation of the meaning of the skies, one must make the friendship of the stars; watch their majestic march through the night, and the slow seasonal advance of constellation after constellation from east to west throughout the year. To know Orion, Sirius, Taurus, and the Pleiades as leading roles of the winter skies; or Lyra, with its Vega, Cygnus, with its Northern Cross, the Scorpion and Antares as the quieter leaders of the softer skies of summer, gives one a sense of kinship with nature which makes a knowledge of their movements more significant, and even life a bit more worthwhile.”

April is an interesting month to start keeping a record of bright stars seen each evening, within the first hour after sunset. Seven of the 16 stars of first-magnitude or brighter observable from the Coachella Valley are gathered in the western sky, arranged as the huge Winter Hexagon—clockwise starting with its brightest member, Sirius, Procyon, Pollux (with Castor nearby), Capella, Aldebaran, Rigel and back to Sirius to complete the Hexagon—with a bright red star, Betelgeuse, inside. Nearly all these stars will depart between late April and late June, as a result of the Earth’s revolution around the sun.

The morning sky features the planets Venus, Jupiter and Saturn. Mercury has a horizon-hugging apparition low in the morning twilight in April, lingering closely to the lower left of Venus at dawn in middle two weeks of month.

In the morning, the stars—but not the fast-moving planets Mercury and Venus—are in roughly the same positions they will occupy in the evening sky a few months hence: Bright steady Jupiter is in the south to south-southwest, with red twinkling Antares, heart of Scorpius, to its lower right, and steady Saturn to left of Jupiter. Golden Arcturus is in the west, with blue-white Spica to its lower left in the west-southwest. The Summer Triangle of Vega, Altair and Deneb passes overhead, as in evenings in August. Getting up before dawn is a good way to preview the sky of the coming season!

Events to observe:

April 1 at dawn: Venus is 8 degrees to the lower left of the waning crescent moon (13 percent). Binoculars may show Mercury rising in twilight, 10 degrees to the lower left of Venus.

April 1-6 at dusk: Mars and the Pleiades, or Seven Sisters, star cluster are 3 to 5 degrees apart, making a fine sight in the same field of view of binoculars. Mars’ trek across Taurus, at nearly two-thirds of a degree per day this month, will be fun to watch.

April 2 at dawn: Venus is within 5 degrees above the crescent moon (8 percent). Using binoculars, try for Mercury, 9 degrees to the lower left of Venus and 7 degrees left of the moon.

April 7-9: Enjoy a fine gathering of the moon, Mars, Aldebaran, Hyades and Pleiades at dusk.

April 10: Jupiter begins retrograde, and ends nearly 10 degrees farther west on the evening of Aug. 10. Saturn undergoes nearly 7 degrees of retrograde motion from April 30 through Sept. 19. It was a very close conjunction involving Saturn retrograding past the third-magnitude star Gamma in Virgo in the spring of 1952 which caught the attention of this writer, not quite 13 years old at the time.

April 10-23, dawn: Mercury stays no more than 5 degrees to the lower left of Venus, making it easy to locate through binoculars in this otherwise poor, low apparition. Mercury approaches within 4.3 degrees to the lower left of Venus April 15-18. Since these planets approach within 5 degrees but don’t pass each other, this event is known as a quasi-conjunction.

April 12: The moon is 7-12 degrees from Pollux and Castor, a pair of stars 4.5 degrees apart, marking the heads of Gemini, the Twins.

Night of April 13: Around this date each year, as the Earth passes between Spica and the sun, the star appears at opposition, nearly 180 degrees from the sun, and is visible all night. Look for Spica, the brightest star in Virgo, low in the east-southeast at dusk, and low in the west-southwest at dawn.

April 13-15: Mars passes 6.5 degrees north of Aldebaran at dusk. Binoculars give a fine view of the Hyades cluster in the same field as Aldebaran. Note two stars 8 degrees apart, marking tips of the Bull’s horns, 15-17 degrees above Aldebaran.

April 14: The moon is 4 degrees from Regulus, heart of Leo, the Lion.

Night of April 18-19: The full moon is 7-8 degrees from Spica all night.

April 22-26: The waning moon passes Antares, Jupiter and Saturn at dawn. The moon is 7 degrees above Antares on April 22, with close pairings of the moon and Jupiter on April 23 (less than one degree) and the moon and Saturn on April 25 (less than 2 degrees).

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, April 6 and May 4. 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, April 13, from 8 to 10 p.m., with the final one for the season on Saturday, May 11.

Also, remember to check the Impromptu Star Parties link. 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 for the stars of summer, plus telescopic views of Jupiter and its moons, and Saturn’s rings; and some at dusk to observe the moon, Mars and the mix of winter and spring stars. Tentatively, I have predawn sky-watches scheduled each Sunday, and evening sky watches each Monday. Check the link for updates.

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.

Published in Astronomy

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.

Published in Astronomy

February offers beautiful sights for the unaided eye and the eye aided with binoculars—especially for early risers getting out an hour before sunrise.

There’ll be close pairings of the moon with bright Venus just before and after the shortest month of the year—on Jan. 31 and March 2—providing chances to spot Venus in the daytime with binoculars and even the unaided eye. Venus and Saturn will appear just 1.1 degrees apart on Feb. 18. It’ll be worthwhile to watch that pair for changes on several adjacent mornings.

Planets at dawn: The pairing of Venus and the crescent moon on Thursday, Jan. 31, will be unusually close and very striking, before dawn and even long after sunrise. From the Coachella Valley, Venus and the center of the moon’s disk will be just 1.5 degrees apart and closing at 5 a.m. Sunrise occurs in Palm Springs at 6:43 a.m., with Venus just more than a degree from the moon’s center, or three-quarters of a degree from the moon’s edge. The closest approach of the moon and Venus occurs in daytime, between 9:45 and 10 a.m., with Venus about 0.4 degrees—less than the moon’s half-degree width—from the moon’s northern cusp the (upper point of the crescent). From 8:30 a.m. through 11:15 a.m., Venus will appear no more than a moon’s width from the moon’s edge. A telescope at low power will fit Venus and the moon in the same field, with Venus showing a gibbous disk, 62 percent illuminated.

At the next, wider moon-Venus pairing on March 2, Venus will appear nearly 4 degrees to the lower left of the moon. A telescope then shows the planet’s phase increased to 73 percent full, but reduced in apparent size as it will be more distant from Earth.

Near the dates of these moon-Venus pairings, the moon can be seen close to two other planets in the morning sky: The moon will appear 5 degrees to the upper right of Jupiter on Jan. 30; 4 degrees to the lower left of Saturn on Feb. 2; within 2 degrees above Jupiter on Feb. 27; and 2 degrees to the upper right of Saturn on March 1.

Planets, stars and moon at dusk: Mars is high in the southwest to west-southwest, halfway or more from horizon to overhead. While fading slowly from magnitude +0.9 to +1.2, Mars is bright enough not to be confused with any star while the red planet passes through the background of Pisces and Aries. The brightest star nearby is second-magnitude Alpha in Aries, about 10 degrees north of the planet in late February. Begin looking for Mercury emerging from the far side of the sun around Feb. 10, when it shines at magnitude -1.3 and sets south of west at mid-twilight, about 40 minutes after sunset. Still bright at magnitude -0.3 when it climbs to 9 degrees up at mid-twilight on Feb. 26, Mercury then begins to fade more rapidly. It’s still magnitude 0.0 on March 1, but, moving to the near side of the sun and becoming a backlighted crescent, it fades beyond magnitude +1 by March 5 and drops back into bright twilight.

Stars and moon: The moon is visible at dusk from Feb. 5 (very low in the west-southwest in early dusk), through Feb. 19 (just past full, risen north of east). The moon passes 6 degrees south of Mars in Aries on Feb. 10; 1-2 degrees north of Aldebaran in Taurus on Feb. 13; 7 degrees south of Pollux on Feb. 16; and 7 degrees above Regulus in Leo at dusk on Feb. 18. That evening, the Earth passes between the sun and Regulus, and that star appears at opposition, 180 degrees from the sun. The direction of Earth’s orbital motion around the sun on this night is away from the Pleiades in the evening sky and toward a spot about 3 degrees west of the third-magnitude star Beta in the head of Scorpius in the morning sky. At the end of February, our planet is moving away from Aldebaran, eye of Taurus, and toward Antares, heart of Scorpius.

The huge Winter Hexagon occupies much of the southeast quadrant of the sky at dusk. Start with Sirius, its brightest star, and go clockwise around its perimeter, to Procyon, the Twins (Pollux and Castor), Capella, Aldebaran, Rigel and back to Sirius. Orion’s shoulder Betelgeuse is inside. Regulus rises into view at dusk during February and chases the Hexagon across the sky. Note Regulus about to set in the west on the morning twilight chart, available with the online version of this article.

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 have a star party starting at dusk on Saturday, Feb. 2. The primary, more-accessible location is 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). The next session there is on Saturday, Feb. 9, from 6 to 9 p.m. Listings of star parties on the website include maps and directions for both locations. Star parties can be cancelled in poor observing weather.

Also, remember to check the Impromptu Star Parties link on the 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 at predawn to follow the three morning planets, and some at dawn or dusk to observe the 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.

Published in Astronomy

6:37 p.m. PST on Sunday, Jan. 20: The moon enters penumbra. The edge of the penumbral shadow will not be noticed, but the moon may seem especially bright then, because the moon most strongly reflects light back toward the source—the sun (and Earth, when the moon is just outside the Earth’s shadow). Look up opposition effect.

7:34 p.m.: Moon enters umbra. The moon begins to enter the dark central core of the Earth’s shadow. How long before this will you first notice the inner penumbral darkening on the moon’s east-southeast edge? How many minutes after first umbral contact will you notice the circular edge of the Earth’s shadow? When will you first notice any color within the shadow?

8:41 p.m.: Total eclipse begins. A few minutes before this time, the almost totally eclipsed moon, with a northwest-north-northwest narrow edge still in sunlight, is likely to be strikingly beautiful. Within the shadow, watch for reddish colors on the moon from sunlight which has passed through the Earth’s atmosphere and been refracted onto the moon. Use the 5-point Danjon scale and select the L number from 0 to 4, which best fits the description of the brightness and color of the moon in total eclipse. Use your own words to describe the eclipse! Repeat at greatest eclipse, and again at the end of totality. If you’re in a dark place during totality, enjoy views of the stars in the absence of bright moonlight. Look for the Beehive star cluster 6 degrees east of the moon.

9:12 p.m.: Greatest eclipse. The moon is closest to the center of the Earth’s shadow. Can you detect any color? Again, use the Danjon scale. Normally, we expect the eclipsed moon to appear darkest around this time. Note the “Twins” Pollux and Castor, 10-15 degrees to the upper left of the moon, and the “Little Dog” star Procyon, 17 degrees to the moon’s lower right.

9:43 p.m.: Total eclipse ends. Again, use the Danjon scale and your own words to describe the eclipse. Now, a few minutes after this time, when a narrow edge of direct sunlight illuminates the northeast edge of the moon, the nearly totally eclipsed moon is likely to be very beautiful.

10:51 p.m.: Moon leaves umbra, or dark central core of Earth’s shadow. How long after this time can you still notice any penumbral shading on the moon’s west-west-southwest edge?

11:48 p.m.: Moon leaves penumbra. You will not notice darkening near this time, but it is around this time we can expect the moon, just outside Earth’s shadow, to shine with extra brilliance. Adding to this opposition effect, the moon at perigee during this eclipse and the Earth-moon system being just a few weeks past perihelion (closest to Sun) combine to further increase the moon’s brightening.

• After January 20, 2019, the next total lunar eclipse visible in parts of U.S. will be on the morning of Wednesday, May 26, 2021; the total phase will be seen from all locations west of a line from east Texas/western Louisiana to eastern Montana. From California, the moon begins to enter umbra, or the dark central core of Earth’s shadow, at 2:45 a.m., followed by a brief, 15-minute totality from 4:11 a.m. until 4:26 a.m. The moon will then be low in the southwest, and morning twilight will be getting under way. The northern edge of the moon will be just barely within the umbra and should be noticeably brighter than the rest of the totally eclipsed moon. The star Beta in the head of Scorpius will be only two degrees north of the moon during totality. From the Coachella Valley, the moon will set a few minutes before completely exiting the umbra, but most of the California coast will be able to see the fully sunlit lunar disk for a few minutes after it departs from the umbra at 5:52 a.m.

• A very deep partial lunar eclipse (magnitude 97.4 percent) will be seen throughout the U.S. on the night of Nov. 18-19, 2021. From Western states, the moon enters the umbra at 11:19 p.m. on Thursday, Nov. 18. Greatest eclipse occurs at 1:03 a.m. early on Friday morning, Nov. 19. A very narrow brightly sunlit southern edge of the moon remains outside the umbra at greatest eclipse, while the rest of the disk shows dark grey or rusty brown hues. It should be a beautiful sight! At deepest eclipse, the Pleiades star cluster will be within 6 degrees north of the moon. The moon moves completely out of the umbra at 2:47 a.m.

• A deep total lunar eclipse will be seen from the contiguous 48 states on the night of May 15-16, 2022. Some western states will miss the start of the initial umbral phase, and northwest Washington state misses the start of totality. From Palm Springs and the Coachella Valley, the moon hasn’t risen yet when it begins to enter the umbra on Sunday, May 15 at 7:28 p.m. The eclipse is total for 85 minutes beginning at 8:29 p.m., during evening twilight. At deepest eclipse at 9:11-9:12 p.m., the northern part of the totally eclipsed moon should appear very dark as it passes through the center of the Earth’s shadow. As totality ends at 9:54 p.m., the moon is 11 degrees east of Alpha Librae and 7 degrees west of Beta Scorpii. Note the reddish (eclipse-colored?) star Antares, heart of the Scorpion, 14 degrees to the lower left of the moon. The concluding partial eclipse ends as the moon completely leaves the umbra at 10:55 p.m.

• A deep total eclipse on morning of Tuesday, Nov. 8, 2022 will be seen throughout U.S. For parts of the East Coast, the moon sets near the end of total eclipse. From California, the moon enters the umbra at 1:09 a.m. A long 85-minute totality, second of the year, occurs from 2:17 a.m. until 3:42 a.m. At deepest eclipse, at 2:59 a.m., the southern part of the moon should appear very dark as it passes through the center of Earth’s shadow. At the same time, Uranus, of magnitude 5.7, is easily seen in binoculars only 1.7 degrees to the upper left of the reddened moon; a telescope will reveal the planet’s greenish disk. The concluding partial eclipse ends at 4:49 a.m. as the moon completely leaves the umbra.

Published in Astronomy

The opening month of 2019 features outstanding sights for the unaided eye, as well as the eye aided with binoculars and telescopes.

Who would fail to wonder at the sight of brilliant Venus near a predawn crescent moon? Separated in time by about a month, we have close pairings on Jan. 1 and 31, providing two easy chances to locate Venus in the daytime with the unaided eye and binoculars. Telescopic views reveal Venus’ changing phase, from 48 to 62 percent this month, and its shrinking apparent size as the planet moves from the near side toward the far side of its nearly circular orbit around the sun.

Venus in January shines at magnitude -4.6 to -4.3, faded some since its peak in early December, but still at its best for 2019. Rising in a dark sky three hours or more before sun-up, it remains impressive!

Another astronomical highlight is a total lunar eclipse, on Sunday, Jan. 20, during convenient evening hours. The partial phase of the eclipse gets under way at 7:34 p.m. as the moon begins to encounter the umbra, or dark central core of Earth’s shadow. After several minutes, the curvature of the shadow’s edge will become obvious. At 8:41 p.m., the eclipse becomes total, and remains so for 62 minutes, until 9:43 p.m. A complete timetable of the eclipse appears on the January 2019 Sky Calendar (click link or see below; right click on the image and view in a new window), which also provides illustrations of that month’s outstanding planetary and lunar gatherings described in the following paragraphs. See also our separate article on the eclipse.

With the deepest total eclipse happening at 9:12 p.m. PST, should you encourage young children to observe this lunar eclipse? Well, if you miss this opportunity, the next chance to catch one during convenient evening hours won’t come until May 2022.

Planets at dawn: On New Year’s morning, Jan. 1, around 6 a.m. in the Coachella Valley, face southeast to enjoy a predawn lineup of the crescent moon with three planets to its lower left, in order: Venus, Jupiter and Mercury. Venus then is within 4 degrees to the lower left of the crescent moon, with Jupiter 18 degrees to the lower left of Venus; and Mercury 13 degrees to the lower left of Jupiter. When the moon reaches its highest point in the south, around 8:22 a.m. that day, Venus is an easy find within 3 degrees to the moon’s lower left—even though it’s daytime. Watch the waning crescent moon slide downward past three planets before sun-up Jan. 1-4.

On Thursday, Jan. 3, Jupiter appears 4 degrees to the upper right of the moon, while Mercury appears 12 degrees to the moon’s lower left. On Jan. 4, Jupiter appears 16 degrees to the lower left of Venus, while the thin old moon appears the same distance to the lower left of Jupiter, with Mercury, in turn, 2.5 degrees to the lower right of the moon. Mercury is getting lower each morning. Its departure after a few more days leaves two bright planets remaining. Masquerading as the two brightest “stars” in the entire predawn sky, the Venus-Jupiter pair becomes ever more striking as it closes to 10 degrees apart on Jan. 11, 5 degrees on Jan. 17, and a shortest distance of 2.4 degrees on Jan. 22. On the latter date, use binoculars to try to see Saturn just emerging from the morning twilight glow, 28 degrees to the lower left of the bright pair. Rising longer ahead of the sun and higher each morning, Saturn within a few days will become easy to see with unaided eye, and we’ll again see three naked-eye planets. From late January through mid-February, their arrangement from the upper right to the lower left will be Jupiter-Venus-Saturn. The waning crescent moon slides past this lineup, producing close pairings with planets on Jan. 30-Feb. 2.

The pairing of Venus and the crescent moon on Thursday morning, Jan. 31, will be unusually close and very striking, before dawn and for long after sunrise. From the Coachella Valley, the angular distance between Venus and the center of the moon’s disk will be just 1.5 degrees and closing at 5 a.m. By 6 a.m., the distance closes to 1.2 degrees. Sunrise occurs in Palm Springs at 6:43 a.m., with Venus just more than a degree from the moon’s center, or three-fourths of a degree from the moon’s edge. The closest approach of the moon and Venus occurs in daytime hours, between 9:45 and 10 a.m., with Venus about 0.4 degrees—less than the moon’s half-degree width—from the moon’s northern cusp (the upper point of the crescent). From 8:30 through 11:15 a.m., Venus will appear no more than a moon’s width from the moon’s edge. A telescope at low power will fit Venus and the moon in the same field, with Venus showing at gibbous phase, 62 percent illuminated.

At dusk: Mars is high in the south-southwest to southwest at dusk, halfway or more from horizon to overhead. Although fading slowly from magnitude 0.5 to 0.9, Mars shouldn’t be confused with any star while the red planet passes through the background of Pisces, which includes no stars brighter than magnitude 3.6.

In early January at dusk, the Summer Triangle of Vega, Altair and Deneb is still easy to see, with Vega and Deneb above in the northwest, and Altair in the west. Fomalhaut, mouth of the Southern Fish, is in the south-southwest, and the earliest stars of winter—Capella in the northeast to east-northeast, and Aldebaran in the east—are prominent. Although Aldebaran marks the eye of Taurus, its Arabic name means “The Follower,” of the Pleiades star cluster 14 degrees above it.

By early January, Orion’s Betelgeuse and Rigel, with his vertical three-star belt between them, have appeared above the eastern horizon. Two more of winter’s bright stars soon follow: Watch for their risings in twilight, by mid-January—first, Procyon in the east, and finally Sirius, the brightest nighttime star, in the east-southeast, below and in line with Orion’s belt. Sirius completes the nearly equilateral Winter Triangle with Procyon and Betelgeuse. When Sirius first appears low in the east-southeast, Altair is still visible, very low just north of west (if no mountains block your view), and both the Summer and Winter Triangles can be seen simultaneously.

The waxing moon returns to the early evening twilight scene as a thin crescent low in the southwest to west-southwest on Jan. 6; passes Mars on Jan. 12; skips past Aldebaran Jan. 16-17; and appears full to the lower right of the “Twin” stars Pollux and Castor on Sunday, Jan. 20, the same evening as the total lunar eclipse.

The website of the Astronomical Society of the Desert (www.astrorx.org) has a listing of our evening star parties at two locations. Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have a star party starting at dusk on Saturday, Jan. 5. Our primary, more-accessible star-party site is 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 monthly star party there is scheduled for Saturday, Jan. 12, from 5 to 8 p.m. Star parties can be cancelled in poor observing weather.

Also, check the Impromptu Star Parties link. 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 Venus’ conjunctions with the moon and other planets. Members of the Astronomical Society of the Desert may be offering a lunar eclipse watch at one or more locations on Sunday, Jan. 20.

On Friday, Jan. 18, I’ll present a preview of 2019’s sky events, including Sunday’s total lunar eclipse, and the year’s beautiful planetary gatherings. The talk begins at 7 p.m. at the Portola Community Center, 45480 Portola Ave., in Palm Desert.

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. The January 2019 issue of the calendar features the total lunar eclipse happening after nightfall on Jan. 20, and the four bright planets in the morning sky.

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.

Published in Astronomy

In December 2018, Venus is an outstanding predawn sight for the unaided eye, as well as binoculars and telescopes.

Who would fail to wonder at the sight of brilliant Venus near a predawn crescent moon? Separated in time by about a month, Venus-moon pairings on Dec. 3 and Jan. 1 provide easy chances to locate Venus in the daytime with the unaided eye. Telescopic views reveal Venus’ changing phase—28 and 48 percent on those respective dates—coupled with a shrinking apparent size as the planet recedes from Earth. When Venus appears half-full just a few days into the new year, it will be “rounding the bend,” moving from the near side into the far side of its nearly circular orbit around the sun, as Venus’ orbit is viewed nearly edge-on from planet Earth.

Venus, about 25 percent full in early December, gleams at magnitude -4.9, as bright as it ever gets. Rising in a dark sky more than three hours before sunup, it’s truly very impressive!

At dawn: On Saturday, Dec. 2, an hour before sunrise, Venus appears 17 degrees to the lower left of a waning crescent moon, and 7 degrees to the lower left of blue-white first-magnitude star Spica. On Monday, Dec. 3, Venus will appear only 4 degrees to the lower right of the moon. To catch Venus at its best, I am leading sky-watching sessions in Palm Springs from 5 to 5:45 a.m. on both those mornings, if sky is clear, on the pedestrians-only bridge over Tahquitz Creek, at Camino Real between North and South Riverside drives. Parking is available on Camino Real, both north and south of the bridge.

On Dec. 4, the moon has moved 10 degrees to the lower left of Venus, and Mercury is visible in binoculars 17 degrees to the lower left of Venus. On Dec. 5, the last old crescent moon easy to see with the unaided eye is 22 degrees to the lower left of Venus, with brightening Mercury just 4 degrees below the thin moon. Mercury then begins a nearly month-long appearance low in the east-southeast to southeast, to the lower left of Venus.

On Dec. 6, if skies are very clear just 30 minutes before sunrise, if you use binoculars and have an unobstructed view toward the east-southeast, you’ll have a chance to spot a very thin, old crescent moon only 17 hours before new, rising 35 degrees to the lower left of Venus and 10 degrees to the lower left of Mercury. We might even spot Jupiter just 3 degrees to the lower right of the hyper-thin moon. I have selected a site in a residential area on the high slopes of northwestern Palm Springs with an excellent view of these rare events on the morning of Dec. 6; watch the Independent’s social media for an announcement of the location if the weather allows for it.

From Dec. 7-21, the moon is absent from the morning twilight sky. Within a few days, Jupiter becomes easy for unaided eye, staying 9 degrees to the lower left of Mercury through Dec. 11 as both rise higher daily. For several mornings, the arrangement of three planets from upper right to lower left is Venus-Mercury-Jupiter. But Mercury, entering the far side of its orbit beyond the sun, passes just 0.9 degrees to the upper left of Jupiter on Dec. 21—look for the striking pair 26 degrees to the lower left of Venus. Thereafter, until Mercury sinks into the sun’s glare in early January, the order of the three planets is Venus-Jupiter-Mercury.

The moon returns to the morning sky, fully illuminated, low in the west-northwest in dawn mid-twilight on Dec. 22. The waning gibbous moon will pass 8-12 degrees to the left of the Twins, Pollux and Castor, on Dec. 24, and 3 degrees to the right of Regulus, heart of Leo, on Dec. 26. A fat crescent moon, just past last quarter (half-full) phase, will appear within 7 degrees to the upper left of Spica in Virgo on Dec. 30. The waning crescent moon will appear within 4 degrees to the upper right of Venus on New Year’s morning, and slide downward past Antares, Jupiter and Mercury over the next three mornings.

At dusk: Mars is high in the sky, halfway from horizon to overhead, in the southern sky in December. Although fading slowly from magnitude 0 to +0.4, Mars shouldn’t be confused with any star this month, while the red planet passes through the background of Aquarius and Pisces, which include no stars brighter than magnitude 3. Saturn can be glimpsed very low in the southwest to west-southwest in early December, before its conjunction with the sun on Jan. 1.

In early December, the Summer Triangle of Vega, Altair and Deneb is still well up in the western sky. Fomalhaut, mouth of the Southern Fish, is in the south. The earliest harbinger stars of winter—Capella in the northeast and Aldebaran lower in the east-northeast—have arrived. Aldebaran, eye of Taurus and “Follower” of the Pleiades star cluster, is at opposition to the sun on Dec. 1 and visible from dusk to dawn.

The waxing moon appears at dusk as a thin crescent very low in the southwest to west-southwest, 3 degrees to the lower right of Saturn on Dec. 8, and 9 degrees to the upper left of Saturn on the next evening. The moon appears almost half-full, 4 degrees to the lower left of Mars, high in south on Dec. 14, and almost full, 3 degrees to the upper right of Aldebaran in the east, on Dec. 20. On Dec. 22, the full moon appears very low in the east-northeast at dusk, opposite to the sun’s direction below the west-southwest horizon. By then, Orion’s Betelgeuse and Rigel have appeared above the eastern horizon. The rest of early winter’s bright stars soon follow. Watch for their risings a little later in the evening in December, or in twilight by mid-January, in this order: Castor, Pollux, Procyon and finally Sirius, the brightest nighttime star. Sirius completes the nearly equilateral Winter Triangle with Procyon and Betelgeuse. As a check, Orion’s belt points downward toward Sirius rising in the east-southeast. When Sirius first appears, Altair is still visible, low, just north of west (if mountains don’t block your view)—and both the Summer and Winter Triangles can be seen simultaneously.

After nightfall: Here’s an easy chance to see our solar system’s two outermost planets. At the end of evening twilight, as soon as the sky becomes fully dark, 5.7-magnitude Uranus is visible in binoculars, closely north-northeast to north of 4.3-magnitide Omicron in Pisces. Point your telescope at Mars, and you’ll find eighth-magnitude Neptune in the same low-power field for four evenings: within 1 degree east-northeast of Mars on Dec. 5; one-third of a degree east-northeast of Mars on Dec. 6; one-third of a degree west-southwest of Mars on Dec. 7; and 1 degree west-southwest of Mars on Dec. 8. To distinguish Uranus and Neptune from faint stars, use these finder charts provided by Sky and Telescope magazine: www.skyandtelescope.com/observing/ice-giants-neptune-and-uranus.

Star parties: The website of the Astronomical Society of the Desert at www.astrorx.org has a listing of our evening star parties at two locations. Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have a star party starting at dusk on Saturday, Dec. 8. Our primary, more-accessible star-party site is 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 monthly star party there is scheduled for Saturday, Dec. 15, from 5 to 8 p.m. Star parties can be cancelled in poor observing weather. Also, check the Impromptu Star Parties link. I’ll be offering sky watches in Palm Springs at the pedestrian bridge over Tahquitz Creek at North Riverside Drive and Camino Real.

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. The January 2019 issue of the calendar and this column in Coachella Valley Independent will preview the total lunar eclipse happening after nightfall on Jan. 20, and the four bright planets in the morning sky.

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.

Published in Astronomy

In November 2018, Venus is the up-and-coming morning “star.”

Next inward from Earth in our solar system, fast-moving Venus overtook our planet in late October while passing nearly between Earth and sun. Day by day in November, Venus rockets higher into the southeastern morning sky. Rising in twilight a full hour before sunup by Nov. 4, Venus’ rising time improves to two hours before sunup on Nov. 13, and three hours before on Nov. 27. (Graphic credit: Jeffrey L. Hunt.)

As it becomes visible in a dark predawn sky before the onset of twilight, Venus also increases in brilliance to magnitude -4.9—as bright as it ever gets. That’s easily bright enough to spot it in the daytime. One easy way to do that is to find Venus before sunup, and keep track of it until after sunrise.

This is the best time to enjoy Venus through a telescope, or even binoculars. On Nov. 1, Venus shows as a very thin crescent, less than 2 percent illuminated, and a full arcminute (one 60th of a degree) across. A magnification of just 30 power then makes Venus appear a half-degree across, about as large as the moon with the unaided eye. The illuminated portion of the crescent Venus thickens to 5 percent by Nov. 7; 10 percent by Nov. 13; 15 percent by the 19th; and 25 percent by the 30th. By month’s end, the apparent size of Venus has shrunk to 0.7 arcminute—still large enough to resolve the crescent shape with 7-power binoculars.

Observe Venus early enough for the sky to be dark—an hour before sunrise is enough—and you’ll notice it has a stellar companion close by. It’s blue-white first-magnitude Spica, within 5 degrees of Venus Nov. 4-28; within 2 degrees Nov. 10-19; and as close as 1 1/4 degrees on Nov. 14. This type of pairing—where a planet approaches a star or another planet within 5 degrees, but doesn’t pass it—is called a quasi-conjunction. You might think of this month’s rare Venus-Spica event to be a “kissing conjunction,” where the participants get so close … but then one of them has a change of mind.

Enjoy these various aspects of Venus this month, despite the early hour, especially after we change our clocks back to standard time on Nov. 4. You won’t regret it!

Our morning twilight map for November shows Venus ascending over the east-southeast horizon to join Spica. Next in brilliance after Venus is Sirius, the Dog Star, in the southwest. It is the southern vertex of the huge Winter Hexagon, also including (in clockwise order) Procyon, Pollux and Castor; Capella at the northern vertex; Aldebaran; and Rigel, with Betelgeuse inside. Regulus, heart of Leo, follows the Hexagon across the sky, and golden orange Arcturus follows Regulus. The waning crescent moon appears near Regulus on the mornings of Nov. 1 and 2. On Sunday, Nov. 4, get out early to watch for Venus rising 26 degrees below the moon. On the 5th, the moon is 13 degrees to the upper left of Venus, and on the 6th, the last thin old crescent moon, some 25 1/2 hours before the new moon, is 9 degrees to the lower left of Venus.

The moon returns to the scene on Thanksgiving morning, Nov. 22, with the nearly full moon about to set in the west-northwest, 19 degrees to the lower right of Aldebaran, and 13 degrees to the lower left of the Pleiades star cluster. On this date, Spaceship Earth is heading directly toward Regulus, 90 degrees from the sun, and is passing between the Pleiades and the sun—so that cluster is at opposition, setting in the west-northwest as the sun rises in the east-southeast. Go out that morning, and visualize the motion of Earth around the sun, with Venus pulling farther ahead of us. The stars drift farther west each day, as shown by their tracks on the twilight maps—a direct result of the Earth’s revolution around the sun. Venus will “round the bend” in our view of its orbit in early January 2019, and next will head toward the far side of the sun, where it will pass, invisibly, in August.

On the mornings of Nov. 23 and 24, the moon will leapfrog past Aldebaran. The waning gibbous moon will appear to the lower left of the “Twin” stars Pollux and Castor on the morning of Nov. 26, and to their upper left the next morning. The moon will appear closely to the upper left of Regulus on Nov. 29.

On our evening twilight chart for November, the Summer Triangle passes west of overhead; Mars remains in the south-southeast with Fomalhaut lower down; and Saturn gets lower in the southwest. Arcturus sinks into the west-northwest twilight glow, while replacement Capella ascends in the northeast. Late in the month, below the Pleiades, watch for Aldebaran rising in the east-northeast to the lower right of Capella. Binoculars, very clear skies and an unobstructed view toward the west-southwest to southwest will be needed to spot Jupiter and Mercury, and only early in month. If all these conditions are met, you might try for Mercury 5-6 degrees to the left of Jupiter on Nov. 1 and 2. Jupiter drops out, but Mercury lingers for another week. Try for Mercury 9 degrees to the left of the 2 percent crescent young moon on Nov. 8, and 7-8 degrees below the 6 percent moon on Nov. 9.

It will be much easier to spot Saturn within 8 degrees to the upper left of the moon on Nov. 10, and within 5 degrees to the lower right of the moon on Nov. 11. Mars will appear only about 2 degrees to the upper left of the 54 percent moon, just past first quarter phase, on Nov. 15. One week after it passes Mars, on Thanksgiving evening, Nov. 22, the full moon will rise just 3 minutes after sunset, although with all the mountains surrounding us, it would be impossible to verify. That evening, as the sky darkens, look for the Pleiades cluster 9 degrees to the moon’s upper left, and Aldebaran, the “follower” of the Pleiades, 11 degrees to the moon’s lower left. On the next night, Nov. 23, the moon rises about 50 minutes after sunset. Look for Aldebaran 3-4 degrees to the upper right of the rising moon. Binoculars will help. On Sunday, Nov. 25, the month’s northernmost moonrise occurs 2 hours and 40 minutes after sunset, well after the end of twilight, so the sky will be very dark for a short time before it brightens again due to moonlight. Within an hour after the moon appears, look for Orion to the right of the moon, and the “Twin” stars Pollux and Castor, 12-14 degrees to the moon’s left.

The website of the Astronomical Society of the Desert at www.astrorx.org has a listing of our evening star parties at two locations. Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have a star party starting at dusk on Saturday, Nov. 10. Our primary, more-accessible star-party site is 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 monthly star party there is scheduled for Saturday, Nov. 17, from 5 to 8 p.m. Also, beginning in late October, check the Impromptu Star Parties link. I’ll be offering sky watches in Palm Springs at the pedestrian bridge over Tahquitz Creek at North Riverside Drive and Camino Real—at dusk to catch Saturn while it’s still visible, and at dawn to welcome Venus as the morning star.

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.

Published in Astronomy

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