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Last updateTue, 18 Sep 2018 1pm

Evenings in August feature a spectacular panorama of four planets, including Venus, Jupiter and Mars far outshining all nighttime stars, and Saturn, ranking sixth in brilliance, after only those three planets and the stars Arcturus and Vega.

Set up a telescope and share views of these four showpiece planets. For best results, view them in order from west to southeast at dusk: 1. Venus changes from gibbous to crescent phase, 57 percent full on Aug. 1, to 40 percent on the 31st. (Venus will be even more impressive in September, as it goes through thinner crescent phases, with the disk growing in apparent size as Venus approaches Earth.) 2. Jupiter shows its cloud belts and as many as all four of the bright moons discovered by Galileo. 3. Saturn displays its rings still tipped a generous 26 degrees into our view, with satellite Titan in a 16-day orbit. 4. Mars’ south polar cap of frozen carbon dioxide is shrinking with the advance of its spring season—look soon! View other surface features, such as Syrtis Major and Hellas Basin, provided that Martian dust storms don’t obscure our view.

Catch Mercury low in the east-northeast to east during morning twilight in late August and early September.

August is a prime month for early evening viewing of the Milky Way. The best dates—at the end of evening twilight, with no moonlight—are Aug. 1-13, and Aug. 30-Sept. 11. From a dark location, follow the Milky Way band from the “cloud of steam” (the Greater Sagittarius Star Cloud) just above the spout of the Teapot, through the Cygnus Star Cloud along the neck of the Swan within the Summer Triangle, and beyond. Viewed through binoculars, the Cygnus Star Cloud easily resolves into stars.

Aug. 1 at dusk: Four planets—in order from west to southeast, Venus-Jupiter-Saturn-Mars—span 127 degrees. A line from Venus to Jupiter, 49 degrees long, extended its own length past Jupiter locates Saturn. Extend another 30 degrees past Saturn to find Mars. Telescopes now show Venus as a gibbous disk 57 percent lit. Mars, just two nights past closest approach, still shines at magnitude -2.8 and shows a disk large enough for a magnification of 80-power to make it look as large as the moon with the unaided eye!

Aug. 4, dawn: It’s the last quarter (half) moon.

Aug. 5, dusk: Venus and Jupiter are 45 degrees apart; Saturn and Mars are 27 degrees apart through Sept. 5.

Aug. 6, predawn: The crescent moon, Hyades and Aldebaran look spectacular in binoculars! While you’re out with your binoculars, view the Pleiades “Seven Sisters” cluster about 14 degrees above Aldebaran.

Aug. 6, dusk: Earth’s current orbital velocity around the sun is 18 miles per second, toward the constellation Aries in the morning sky, and directly away from Jupiter and the constellation Libra in the evening sky. An hour after sunset, when the sun is below the west-northwest horizon, try to visualize the motions of all the planets visible at the time. An observer viewing from north, or “above,” the solar system, from the direction of the constellation Draco, would observe all the planets revolving counterclockwise around the sun. Venus, moving faster, is catching up with Earth and will overtake us in late October. In the last three months, we have overtaken all three bright outer planets—Jupiter in early May, Saturn in late June, and Mars in late July (on dates of their oppositions). We are now headed directly away from Jupiter, and are leaving all three of those slower-moving planets behind.

Aug. 7, dusk: Venus, Jupiter, Saturn and Mars span 120 degrees.

Aug. 8-10, dawn: Follow the moon’s last days of the lunar cycle in the morning sky. On Aug. 9, Pollux is 9 degrees to the left of the moon (a 6 percent crescent) and slightly higher. Castor is 4-1/2 degrees to the upper left of Pollux. On Aug. 10, the moon (only 1 percent) rises in twilight 14 degrees below and slightly to the right of Pollux. Begin watching below Orion for the first appearance of Sirius in the east-southeast.

Aug. 9, dusk: Venus and Saturn are 90 degrees apart.

Aug. 10, dusk: Venus and Spica are 20 degrees apart. Venus is now going east by a degree per day.

Aug. 12, 30 minutes after sunset: Find the young moon, a 4 percent crescent, 41 hours after new, 23 degrees to the lower right of Venus. Later, on the same night: Perseid meteors peak overnight, best from late in the evening on Aug. 12 until the first light of dawn on Aug. 13, increasing in numbers as the radiant rises higher, from 20 degrees up in the north-northeast as evening twilight ends, to 60 degrees up at start of morning twilight. Meteors can appear anywhere in the sky, but members of this shower, if their tracks are extended backward before their light-up points, would all originate from a common radiant below the “W” of Cassiopeia.

Wrapping up at the end of a night of seeing Perseids, I enjoy watching for the rising of Procyon, the “before the Dog” star in the east, and Sirius “the Dog Star” in east-southeast in morning twilight. (Follow Orion’s belt downward to Sirius.) Completing the Winter Triangle with Orion’s shoulder, Betelgeuse, both Dog stars are visible by an hour before sunrise, when the Summer Triangle of Altair, Vega and Deneb is low in the west to northwest. Can you see the Summer and Winter Triangles simultaneously? You must face different directions to see all six stars!

Aug. 13 at dusk: Venus is growing in apparent size as it approaches Earth, while Mars is shrinking as we recede from it. They now appear the same size, but strikingly different: Brilliant, cloud-covered Venus is half-illuminated, while Mars is 98 percent full, with its shrinking polar cap tipped nearly 10 degrees toward Earth. Watch the moon pass Venus and Jupiter through the 17th.

Aug. 13-Sept. 10 at nightfall: For next four weeks, Mars moves very slowly against the stars, and binoculars will show a striking, compact kite-shaped grouping of four stars of magnitude 4.5 to 4.8 in the same field, within a few degrees west of Mars. The long diagonal of the kite is just more than 2 degrees long, and the short diagonal about 1 degree. The gathering, a Chinese asterism called Dog Nation or Territory of Dogs, consists of the stars Omega, 59, 60 and 62 Sagittarii. For star tales about Sagittarius, including the fascinating Chinese fable about the Territory of Dogs, visit http://www.ianridpath.com/startales/sagittarius.htm and http://www.lcsd.gov.hk/CE/Museum/Space/archive/StarShine/Starlore/e_starshine_starlore14.htm.

Aug. 15 at dusk: The moon is in the west-southwest, 7 degrees to the upper right of Spica. Venus is 15 degrees to the lower right of Spica. Watch Venus close in on Spica for the rest of month..

Aug. 16 at dusk: Jupiter passes 0.6 degrees north of Alpha in Libra, or Zubenelgenubi, the third-magnitude star marking the southern claw of a larger, former version of the Scorpion. Binoculars give a good view.

Aug. 17 at dusk: Venus reaches greatest elongation, 46 degrees from the sun in the afternoon and evening sky. Note Jupiter to the moon’s lower right. The moon is at first quarter (half full) overnight, within an hour after moonset. Mars close up: Syrtis Major passes just north of the center of Mars’ disk at 8:52 p.m.

Aug. 18 at dusk: Jupiter is 25 degrees west of Antares. Watch the moon skip over Antares Aug. 18-19, and pass Saturn and Mars Aug. 20-23. Mars close up: Syrtis Major passes just north of the center of Mars’ disk at 9:29 p.m. (37 minutes later each day).

Aug. 19 at dawn: Mercury ends retrograde, but on the near side of its orbit and backlighted; at magnitude +1.6 this morning, it is a difficult target in bright twilight. It gets easier: Mercury brightens to magnitude +1.0 by Aug. 21, to 0.0 by Aug. 25, to -0.5 by Aug. 28, and to -1.0 by Sept. 3.

Aug. 20 at dusk: Venus and Spica are 10 degrees apart. Mars close up: Syrtis Major passes just north of the center of Mars’ disk at 10:43 p.m. Mars is highest in Palm Springs at 10:58 p.m.—the closest match!

Aug. 23 at dusk: Venus and Jupiter are now within 30 degrees. Later in the night, Mars is at 10:45 p.m., while Syrtis Major passes just north of the center of Mars’ disk at 12:34 a.m. on Aug. 24.

Aug. 24-26, at dawn: Mercury forms a nearly equilateral triangle with Pollux and Procyon, about 23 degrees on a side. Compare to larger Winter Triangle of Sirius, Procyon and Betelgeuse.

Aug. 26: The full moon is at 4:56 a.m. At dawn, Mercury is very low in the east-northeast, at greatest elongation, 18 degrees from the sun. At dusk, for a dozen evenings, through Sept. 6: Venus and Spica are within 5 degrees, and appear closest, 1.3 degrees apart, on Aug. 31. Binoculars give good views of the pair low in twilight.

Aug. 27 at dusk: Mars ends retrograde in far southeast Sagittarius. Binoculars show Chinese asterism, “Dog Nation” or “Territory of Dogs,” closely west of Mars for at least two more weeks.

August 28 at dusk: Venus and Spica are 3.1 degrees apart. The moon rises very nearly as Venus sets.

Aug. 31 at dusk: Venus, Jupiter, Saturn and Mars, span 95 degrees. Venus passes within 1.3 degrees south of Spica (closest tonight). Telescopes show Venus as crescent, 40 percent full, and Mars 94 percent full.


Extras

As mentioned above: Mars this month shows its south polar cap of frozen carbon dioxide, shrinking with the advance of southern spring, as well as surface features, such as Syrtis Major and Hellas Basin best on the nights of Aug. 17-24, provided that Martian dust storms don’t block the view.

As August opens, Mars, just a day past closest approach, still shines at magnitude -2.8 and shows a disk 24.3 arcseconds across. It is mid-spring in Mars’ southern hemisphere, and the bright south polar cap is shrinking noticeably with the approach of Mars to its perihelion in mid-September, and to its southern summer solstice in mid-October.

Syrtis Major, a prominent dark marking first noticed in 1659, will be in good position for observing on the nights of August 17-24 as it passes near the center of Mars’ disk within 2 1/2 hours of when the planet is highest in our local night sky. But Mars is farthest south in mid-August, so it is less than 30 degrees up when due south for residents of the Coachella Valley. Be patient and wait for good seeing. The best times to look for Syrtis Major, which resembles a dark triangular, northward-pointing India passing north of the disk center, occur about 37 minutes later each night, starting on Aug. 17 at 8:52 p.m., and ending on Aug. 25 at 1:11 a.m. At all these same times, look for light-colored Hellas Basin crossing south of disk the center, between Syrtis Major and the polar cap. Martian dust storms might render these surface features difficult or impossible to observe. Let’s hope for clear skies—on Mars as well as on Earth!

The next “windows” for best viewing of Syrtis Major and Hellas occur 36 days later, in late September. Mars will then reach its high point in south about two hours earlier in evening. Between now and then, watch the face of Mars shift by 10 degrees in longitude per day, if you look when Mars passes due south. For a map of Mars for any date and time, visit Sky and Telescope Mars Profiler: https://is.gd/marsprofiler.

See also these detailed descriptions of Mars’ 2018 apparition:

http://www.alpo-astronomy.org/jbeish/2018_MARS.htm

http://www.nakedeyeplanets.com/mars.htm

Asteroid Vesta in August 2018: For much of the month, asteroid Vesta is an easy target for binoculars, and the 3.3-magnitude star Theta Ophiuchi is the starting point and key to locating it. Find Theta Oph 12 degrees east of Antares, nearly halfway toward 2.8-magnitude Lambda Sagittarii, top of the Teapot. Theta Oph is plotted on Sky Calendar diagrams for Aug. 7 and Aug. 17-23. On Aug. 1, Vesta, of magnitude 6.3, ends retrograde 2 1/4 degrees north-northeast of Theta Oph while moving 4 arcminutes southward each day. Note these two stars in the same binocular field to the upper left of Theta: 44 Ophiuchi, of magnitude 4.2 and 1.3 degrees northeast of Theta; and 51 Oph, of magnitude 4.8 and nearly 1.2 degrees east-northeast of Theta. After Aug. 1, Vesta curves eastward. On Aug. 16, a line from Theta to 44 Oph, 1.3 degrees long, extended nearly half its length past 44 Oph, locates Vesta, of magnitude 6.7. The Moon appears near this field on the evenings of Aug. 19 and 20. On the evenings of Aug. 20 and 21, Vesta, of magnitude 6.8 and moving east-southeast by 9 arcminutes per day, appears very close to 4.8-magnitude 51 Oph. The asteroid passes 7 arcminutes south of the star during the day on Aug. 21. For a Vesta finder chart, visit http://www.skyandtelescope.com/observing/vesta-2018-opposition/.

Here’s a link to article on 2018 apparitions of Uranus and Neptune with finder charts:

https://is.gd/urnep

http://www.skyandtelescope.com/observing/ice-giants-neptune-and-uranus/

For suggestions for observing projects during August through October 2018, go to http://abramsplanetarium.org/msta/.

The website of the Astronomical Society of the Desert has a listing of our evening star parties, Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have a star party starting at dusk on Saturday, Aug. 11.

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

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

The summer of 2017 marks the 54th anniversary of my first successful expedition to observe a total solar eclipse.

The date was July 20, 1963, when our carload of astronomy graduate students from the University of Michigan made the long drive from Ann Arbor to the path of totality in Quebec. Cumulus clouds parted—and we had a spectacular view.

When it came to astronomy, I was hooked.

I hope some of you have a chance to make the journey to the August eclipse’s path of totality. This event is part of the Saros series—same as the eclipse I saw in 1963. These eclipses are spaced at intervals of 18 years plus about 11 1/3 days, and after three Saros intervals—called an Exeligmos—a solar eclipse very much like the one in 1963 happens again, within a similar track through our region of the world, only farther south. Instead of Alaska through Canada and Maine as in ’63, the ringside seats on Monday, Aug. 21, will be in Oregon to South Carolina, making this eclipse an exclusively American event.

Even if you can’t go to Oregon or another spot within the path of totality that day, there are many ways to safely observe the partial solar eclipse here. In California, it starts between 9:01 a.m. (on the Pacific Coast near Point Arena) and 9:11 a.m., when the noon’s penumbral (partial) shadow reaches the far southeast corner of the state, on the Arizona border. The moon’s penumbra begins to withdraw from California just after 11:34 a.m., when the eclipse ends on the Pacific Coast near Capetown. The moon’s outer shadow completely leaves the state just south of the Parker Dam on the Colorado River just after 11:55 a.m.

From most locations in California, the first contact of the moon with the sun’s disk occurs near the top of the solar disk (near “12 o’clock” on the disk, if it is imagined as a clock face). At greatest eclipse, the moon covers the upper left portion of the solar disk, centered near the equivalent of 10 o’clock, leaving a brilliant solar crescent uncovered near 4 o’clock. Last contact of the moon’s disk with the sun will occur at the lower left edge of the disk, near the 8 o’clock position. Of course, you must use proper eye protection to observe these events directly; see the web resources below. If you don’t have a solar filter, you can use projection methods.

Follow the moon before the solar eclipse: On Aug. 7, two weeks before the solar eclipse, there will be a full moon, with a partial lunar eclipse—but that event isn’t visible from our part of the world. (It occurs during our daytime, when the full moon, opposite the sun, is below our horizon.) Instead, watch a nearly full moon rise shortly before sunset of Aug. 6, and just a few minutes after sunset on Aug. 7. For the next several evenings, you can watch the moon rising later each night—or, you can shift your moon viewing time to mornings, either in predawn darkness or in the daytime after sunrise. Observe in the predawn darkness hours on Saturday, Aug. 12, and you’ll catch the Perseid meteor shower nearing its peak. Unfortunately, in 2017 the waning gibbous moon, still over three-quarters full that morning, will brighten the sky and reduce the number of meteors seen.

By the morning of Aug. 15, the moon will be just past last quarter phase, when it’s half full and 90 degrees west of the sun, but by then, the meteor shower activity will be well below peak. On the next morning, Aug. 16, look for bright Aldebaran, eye of Taurus, the Bull, just to the upper right of the crescent moon. Observe beautiful pairings of Venus with the waning crescent moon on Aug. 19 and 20.

As for Perseid meteors in evening: After the full moon of Aug. 7, the moon rises later each night, and by Aug. 11, it rises at 10:14 p.m., more than an hour after the end of evening twilight, at 9:08 p.m. In places far from the bright lights of human settlement—such as in Joshua Tree National Park or Borrego Springs—the sky will be very dark before moonrise, allowing spectacular views of the summer Milky Way and of Perseid meteors. Even before 9 p.m., the sky will be dark enough to observe some meteors. They might be seen anywhere in the sky, and the shower’s “radiant,” or the direction from which the meteors approach Earth, can be found by extending their trails backward to a common origin. Around 9 p.m., the radiant lies just a few degrees above the horizon in the north-northeast. When the radiant is low, the meteoroid particles enter Earth’s atmosphere at a very shallow angle, and very long trails of “Earth-grazing” meteors will be seen. As the night progresses, the radiant in the upper part of the constellation Perseus rises to more than 60 degrees above the horizon by the start of morning twilight, shortly after 4:30 a.m., and our part of the Earth will be presented more broadside to the incoming meteor stream. The meteor count would increase dramatically—were it not for the bright moon after it rises into view.

Good news for 2018: The Perseid peak will occur within two days after new moon, on the night of Aug. 10-11, so it will be a wonderful year for the shower!

Seasonal motions of stars: Venus now dominates the predawn sky, but is getting a little lower each morning, because it is heading toward the far side of the sun, where it will arrive in January 2018.

Annually by the beginning of August, there are several bright stars in the eastern morning sky. During the second week, Procyon and the Dog Star Sirius, the brightest star (not as bright as Venus) rise into view. Beginning then, if you catch Sirius rising in the east-southeast before Altair sets just north of west, you’ll see both the Summer and Winter Triangles—Vega, Altair and Deneb in the west to northwest, and Betelgeuse, Procyon and Sirius in the east to southeast—simultaneously, provided mountains don’t block Altair or Sirius from your view.

Follow the moon in the evening sky after the solar eclipse: Careful viewers might spot the young crescent moon early on Tuesday evening, Aug. 22, just 2 or 3 degrees above the horizon about 25 minutes after sunset, where no surroundings obstruct the view. It’ll be much easier to spot the crescent starting on Aug. 23. Through Aug. 31, notice the moon passing by two planets: Jupiter (with Spica nearby) on Aug. 24 and 25, and Saturn (with twinkling reddish Antares to its west) on Aug. 29 and 30.

To help you plan evening or morning planet viewing during the coming year (August 2017 to August 2018), refer to Jeffrey Hunt’s two-page graphic summary of the moon and planet setting and rising times relative to times of sunset and sunrise, exact for Palm Springs.

To help you plan evening or morning planet viewing during the coming year (August 2017 to August 2018), refer to Jeffrey Hunt’s two-page graphic summary of the moon and planet setting and rising times relative to times of sunset and sunrise, exact for Palm Springs, under the August AM sky chart below.

Wishing you clear skies!

Solar Eclipse information and Resources

http://www.skyandtelescope.com/total-solar-eclipse-august-2017/

http://www.skyandtelescope.com/observing/stargazers-corner/solar-eclipse-lab-sunny-day/

http://www.eclipsewise.com/solar/SEnews/TSE2017/TSE2017.html

https://eclipse.aas.org/

https://eclipse2017.nasa.gov/

https://www.astrosociety.org/education/2017-solar-eclipse-information-resources/

http://static.nsta.org/extras/solarscience/SolarScienceInsert.pdf

http://eclipsophile.com/total-solar-eclipses/total-solar-eclipse-2017-august-21/

http://aa.usno.navy.mil/data/docs/Eclipse2017.php

http://www.astronomy.com/great-american-eclipse-2017

https://www.greatamericaneclipse.com/

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 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. Dr. Jeffrey L. Hunt, a retired planetarium director now living in the Chicago area, 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.

Published in Astronomy

Jupiter sets almost an hour after the sun on Aug. 1, and three minutes earlier each evening thereafter. Using binoculars a half-hour after sunset, look very low, about midway between west and west-northwest, to the left of the sunset point.

If you can still find Jupiter on Aug. 5, try for Mercury, 1.9 degrees to its lower right. On Aug. 6, Mercury is 0.6 degrees to the upper right of Jupiter, and on Aug. 7, it is 1.4 degrees to Jupiter’s upper left. The solar system’s largest planet will be hidden for several weeks while it passes conjunction on the far side of the sun on Aug. 26. Meanwhile, Mercury makes a very low evening appearance, 4 degrees above the western horizon in mid-twilight (about 40 minutes after sunset) from Aug. 18 to Sept. 4, staying at magnitude 0 while shifting from 3 degrees north of west to 10 degrees south of west. Jupiter will emerge into the morning sky in September, joining Venus and Mars to form a spectacular compact trioin late October.

Venus passes inferior conjunction, nearly between Earth and the sun, 8 degrees south of the sun’s disk, on Aug. 15. On the morning of Aug. 17, Venus rises 8 degrees to the right of the sun, simultaneously with it. On Aug. 21, Venus rises 30 minutes ahead of the sun; on Aug. 26, just more than an hour before sunup; and by Aug. 30, Venus rises spectacularly in a dark sky 90 minutes before the sun.

Use binoculars or a telescope to observe its thin crescent phase, while avoiding the planet’s glare against a dark sky. Once you start seeing Venus in the morning sky in late August, just keep track of it until sunrise, and you’ll have a daytime sighting of Venus! This “morning star” will be most interesting through binoculars and telescopes from late August through late October.

If you enjoy the simple pleasure of watching the moonrise over a distant landscape, here’s when to look from the mid-Coachella Valley: On July 31, the full moon rises at 7:59 p.m., less than a quarter-hour after sunset. On Aug. 1, moonrise occurs at 8:44 p.m., within an hour after sunset. On Aug. 2, the moon rises at 9:26 p.m., just after the end of twilight. For the next few days, the moon rises about 40 minutes later each evening. By Aug. 4, the moon comes up at 10:47 p.m., three hours after sunset, allowing a nice window of dark skies before moonrise for enjoying the summer Milky Way. Note the summer triangle of Vega, Altair and Deneb plotted on August’s twilight sky charts. On moonless nights, look near the center of the summer triangle for the Cygnus Star Cloud—a bright patch of the Milky Way, containing stars within our own spiral arm. On dark nights, binoculars easily resolve the Cygnus Star Cloud into stars.

Returning to the sky in evening mid-twilight, we notice that Venus, so prominent in July, is absent; Jupiter is present only early in the month; and Mercury hugs the western horizon after Jupiter has departed. That leaves Saturn as the brightest object less than halfway to overhead. Find it in the south-southwest to southwest at dusk, with reddish twinkling Antares, heart of the Scorpion, 13 degrees to its lower left in all of August.

The rings of Saturnare now tipped 24 degrees from edge on. On evenings in August, Earth is in position to allow our best view of the shadow of the planet cast on the rings, giving the scene a beautiful 3-D appearance. Telescopic views are impressive! View Saturn and many deep-sky objects on Saturday, Aug. 15, at the Astronomical Society of the Desert “star party” at Sawmill Trailhead. For additional information, directions and a map, visit www.astrorx.org.

Golden Arcturus, high in the western sky, and blue-white Vega, high in the northeast, both outshine Saturn. Look also for Spica in the southwest, to the lower left of Arcturus and west (lower right) of Saturn.

The moon can be followed in evening twilight daily, Aug. 16-29, as it waxes from a thin crescent, through first quarter phase (half full and 90 degrees east of the sun on Aug. 22), to full.

Mornings during the summer and fall of 2015 will be fascinating for sky watchers. Those who check the eastern sky regularly about an hour before sunrise can watch for the first appearances—called heliacal risings—of planets and first-magnitude stars. Procyon and Sirius will appear by mid-August; Venus before the end of August; Regulus and Jupiter before mid-September; and Arcturus and Spica by the end of October.

This is a great year for the Perseid meteor shower. The peak—in dark skies on the night of Aug. 12-13—nearly coincides with the new moon. Best viewing is from late evening until the first light of dawn. Meteors belonging to this stream could appear anywhere in the sky, since the stream is much wider than planet Earth. However, if you extend the meteors’ trails backward beyond where they light up in the Earth’s atmosphere, they will all streak away from a point in the constellation Perseus, below the “W” of Cassiopeia in the northeastern sky. As evening twilight ends, this radiant point is very low in the sky, resulting in meteors making long trails through Earth’s atmosphere nearly parallel to the ground. During the night, as the Earth rotates, the radiant climbs ever higher in the sky, and our part of the Earth turns more nearly broadside to the incoming meteors. So the count of meteors is expected to be highest just before the start of morning twilight on Thursday, Aug. 13.

Another peak of activity might be seen on the previous morning, Wednesday, Aug. 12. That’s because before noon that day, the Earth passes nearest to a trail of dust left by Comet Swift-Tuttle in 1862. (That comet is the source of material for the Perseid meteors.) If the stream is broad enough, we could see enhanced numbers of meteors on Wednesday morning, too.

Resource: Get a sample issue and subscribe online to the Sky Calendar at www.abramsplanetarium.org/skycalendar.

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.

Published in Astronomy

The full moon occurs on Sunday, Aug. 10, at 11:09 a.m. The moon passes perigee—221,765 miles from Earth, the closest approach of the year—at the same hour.

But this “supermoon,” visible at dawn and dusk on that date, is not the brightest moon of 2014, because of the phase effect, which makes the moon’s brightness decrease sharply when it’s a few degrees away from being exactly 180 degrees from the sun. You can duplicate this effect one night by standing between a stationary bright-light source and a highly reflective road sign, so that the shadow of your head is cast upon the sign. Note how the sign really lights up around your head’s shadow, giving the shadow a brilliant “halo.” However, if you take a step or two to left or right, you’ll notice how quickly the road sign fades away.

August's full moon passes four to five degrees north of Earth’s shadow center, causing the moon to set after sunrise and rise before sunset on Aug. 10. Further, the timing of the full moon, during the daytime, places the moon widely northwest of the Earth’s shadow at sunrise, and northeast of it at sunset.

Even with the moon not as bright as could be, there are no truly dark skies between dawn’s first light on Aug. 8 and nightfall on Aug. 14. This fact will largely spoil this year’s Perseid meteor shower, which would otherwise be at its best in the predawn darkness hours of Wednesday, Aug. 13.

If you’re outdoors that morning as twilight brightens, watch for Jupiter rising in the east-northeast, 5 degrees to the lower left of Venus. Venus goes east against background stars by 1.2 degrees per day compared to Jupiter’s 0.2 degrees; watch their separation narrow by about 1 degree daily.

Don’t miss the spectacular pairing of Venus and Jupiter on Monday, Aug. 18, within 0.4 degrees. Five days later, on Saturday, Aug. 23, the old crescent moon joins the brilliant planets in a beautiful scene.

Evening planets: Find the planets Mars and Saturn in the southwest at nightfall, and compare them in brightness and color to each other; to bluish Spica, to their lower right; and to reddish Antares, to Saturn’s left. The stars will twinkle noticeably.

Watch the Mars-Saturn gap shrink until they’re 3.4 degrees apart on Aug. 25, and then widen to 5.0 degrees apart by Aug. 31. The moon will appear near these planets on Aug. 31.

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.

Published in Astronomy

On this week's cosmic Independent comics page: Jen Sorenson offers a First Amendment/U.S. courts quiz; This Modern World debates the Israel/Palestine conflict; The K Chronicles gets into a cartoon-character scuffle in NYC; and Red Meat enjoys the meteor shower.

Published in Comics

This month, Mars and Saturn draw attention in the southwest evening sky, as they appear within 10 degrees of each other from Aug. 8 on—and within 5 degrees Aug. 19-31.

Viewed through a telescope this month, Saturn—with its shadow cast upon its rings—has a striking three-dimensional appearance.

August 2014 at dusk: The five brightest objects in evening mid-twilight are Arcturus and Vega, near magnitude 0.0; Mars (+0.4 to +0.6); Saturn (+0.5 to +0.6); and Altair (+0.8).

We have our first mutual conjunction of naked-eye planets in the evening sky this year, as Mars passes 3.4 degrees south of Saturn on Aug. 25, in the southwest sky. At dusk on Aug. 31, a thick crescent moon forms a pretty gathering with Mars and Saturn, several hours after a daytime occultation of the ringed planet.

As for stars: Arcturus, Spica, Antares, all in the west half of the sky, sink lower as the month progresses. The Summer Triangle of Vega, Altair and Deneb, well up in the east, ascends still higher.

On Friday, Aug. 1, find the moon in the west-southwest, with a string of bright objects to its upper left: Spica, 6 degrees to the upper left, with Mars 10 degrees to the upper left of Spica, and Saturn 13 degrees to the upper left of Mars. Antares, heart of Scorpius, is 24 degrees to the left of Saturn. During the next four evenings, the moon will be moving eastward through the lineup of these four objects.

On Sunday, Aug. 10, with unobstructed views of the horizon, you can catch the full “supermoon” setting 15 degrees south of west a few minutes before sunrise, and rising 12 degrees south of east a few minutes before sunset. An hour after sunset, the full moon is 12 degrees up in the east-southeast. On Monday, Aug. 11, the moon rises within 40 minutes after sunset.

After full, the waning moon rises later each evening—but not quickly enough to prevent bright moonlight from diminishing the peak of the Perseid meteor shower on the night of Aug. 12-13.

Perseid meteorscan be seen anywhere in the sky, but if the track of a Perseid meteor is extended backward, it will trace back to the radiant in Perseus, to the lower left, or later in the night, below the “W” of Cassiopeia. That’s the direction from which the stream of meteoroids (dust from Comet Swift-Tuttle) approaches Earth. On the evening of Tuesday, Aug. 12, as twilight ends at 9:07 p.m. in the Coachella Valley, the shower radiant is only 8 degrees up in the north-northeast. Meteors seen then won’t be plentiful, but any that are seen will be “Earth-grazers,” with long paths dipping into our atmosphere at a shallow angle.

As twilight ends at 4:35 a.m. on Wednesday, Aug. 13, the radiant is nearly 60 degrees up in the north-northeast to northeast. Meteors will be more plentiful, because our part of the Earth will be presented more broadside to the incoming stream. But this year, the moon will be high and bright, reducing the numbers seen.

On Wednesday evening, Aug. 13, there is a brief half-hour window of dark skies before moonrise, presenting another chance to see Earth-grazers—but not many, because Earth will have moved out of the core of the Perseid stream.

In 2015, the Perseid meteor shower will be a grand spectacle, as the new moon will occur on Aug. 14, only one day after peak.

August 2014 at dawn: The five brightest objects are Venus; Jupiter and Sirius, once they appear in August’s second week; and Vega and Capella.

A spectacular, close pairing of the two brightest planets, Venus and Jupiter, will provide much enjoyment for morning twilight skywatchers in August. On Aug. 8, watch for Jupiter rising in the east-northeast within 10 degrees of the lower left of Venus, moving about a degree closer each day. By Aug. 13, the planets are only 5 degrees apart; on Aug. 18, the two bright planets will appear closest, within 0.4 degrees. They’ll spread to just more than 5 degrees apart by Aug. 23, when a waning crescent moon appears to their right, within 5 to 8 degrees.

As for stars: As this month begins, we see the Summer Triangle in the west to northwest, and Fomalhaut in the south-southwest to southwest, sinking lower with each passing day. In the eastern sky, as August opens, we’re already seeing Capella, Aldebaran, and Orion’s Betelgeuse and Rigel, as described in the opening lines of Robert Frost’s poem “The Star Splitter”; we’re also seeing Venus and Pollux. Joining the spectacle in August’s second week are Jupiter, Procyon and Sirius.

If you look at just the right time, from a place where mountains don’t block your view, you can see the Winter Triangle and Summer Triangle simultaneously, just after Sirius rises and before Altair sets. You can then observe 11 of the 16 stars of first magnitude or brighter ever visible from Southern California.

Check the website of the Astronomical Society of the Desert for dates, maps and directions to our “star parties,” where everyone is welcome to look through our telescopes at the moon, planets and “deep sky objects.” Year-round monthly sessions begin at dusk at Sawmill Trailhead; upcoming dates are Aug. 23 and Sept. 20, as sky conditions permit. Our monthly star parties at the more-convenient Santa Rosa and San Jacinto Mountains National Monument’s Visitor Center will resume on Oct. 4.

Seize opportunities this summer to enjoy the beauty of 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, California. Robert D. Miller, who provided the twilight charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.

Published in Astronomy

At dusk, watch Venus slowly close in on Spica and Saturn, until pairings occur in September.

Meanwhile, the best Milky Way viewing occurs this year on evenings through Aug. 9, and then again Aug. 26 through Sept. 7. Get to a dark site by nightfall, and enjoy!

Dark moonless predawn hours of Aug. 12 and 13 make this an excellent year for the annual Perseid meteor shower. And mid-August, dawn brings forth the greatest number of bright stars visible simultaneously.

Venus continues as the brilliant evening “star” low in evening twilight, while drifting from west to west-southwest as month progresses. Valley residents living closely east of mountains (such as near downtown Palm Springs) will want to seek out a location where the mountains don’t block the planet from view.

Venus will grace our evening sky until early January 2014. Until then, a waxing crescent moon passes Venus monthly, producing the most striking views at dusk on Friday, Aug. 9, and on Sunday, Sept. 8. Don’t miss these!

On our evening all-sky chart above, planets are plotted for each day when the sun has sunk to 9 degrees below the horizon, at “mid-twilight.” By then, two naked-eye planets and a half-dozen stars of first magnitude or brighter are easily seen. In mid-August in the Coachella Valley, mid-twilight occurs about 42 minutes after sunset.

Planet positions are represented by a separate dot for each date, with positions for each Thursday in August (1, 8, 15, 22, 29) represented by a larger dot and labeled. We find Saturn and Spica in the southwest to west-southwest sky this month, to the upper left of Venus. Rotate the chart until the portion of the horizon circle nearest to your target objects is below them, and you’ll see them depicted at the same orientation as they appear in the sky: On Aug. 1, Venus is in the west, with Saturn in the southwest 53 degrees to Venus’ upper left, while Spica is 12 degrees to the lower right of Saturn, and 41 degrees to the upper left of Venus. On Aug. 31, Venus is in the west-southwest, with Saturn 19 degrees to its upper left, while Spica is just 6 degrees to the upper left of Venus, and 14 degrees to the lower right of Saturn.

On the chart, stars’ daily positions are plotted not as individual dots, but instead by continuous tracks as the stars drift west (counter-clockwise around the North Star) over the course of the month, owing to the Earth’s revolution around the sun.

The brightest star in August’s evening sky is golden Arcturus, high in the west-southwest to west, to upper right of Saturn and Spica and forming a large triangle with them. When the sky darkens enough for the Big Dipper to become visible, you can “follow the arc (of the handle) to Arcturus and drive a spike to Spica.”

A close second to Arcturus in brilliance is blue-white Vega, very high in the east-northeast. Compare the contrasting colors of these two stars! To Vega’s lower left is Deneb, and to Vega’s lower right is Altair, completing the Summer Triangle. Face south to south-southwest to find reddish Antares, heart of the Scorpion.

From Aug. 8-21, the moon is above the horizon in evening mid-twilight. Follow it nightly as it waxes, or grows, from a thin crescent on Aug. 8, past first quarter (half full) by Aug. 14, to full on Aug. 20. The moon appears near Venus on Aug. 9, Spica on the 11th, Saturn on the 12th, and Antares on the 15th.

(I recommend the Abrams Planetarium Sky Calendar for its easy-to-follow illustrations of the changing positions of moon and planets against background stars. The current issues feature illustrations of the changing arrangements of Venus-Spica-Saturn at dusk and Jupiter-Mars-Mercury at dawn. Each month, an all-sky evening chart of the constellations is also provided. To subscribe, visit www.pa.msu.edu/abrams/SkyCalendar.)

Star Parties

The Astronomical Society of the Desert hosts free public sky-watching sessions at Sawmill Trailhead on Saturday evenings, Aug. 3, and Sept. 7. For more information and directions, visit www.astrorx.org and www.astrorx.org/sawmill%20Directions.htm.

August Evening Moonrise Watch

The full moon occurs on Tuesday, Aug. 20, at 6:45 p.m. in the Coachella Valley.

That evening, the moon rises nine degrees south of east at 7:05 p.m., about 22 minutes before sunset. Does the full moon at rising seem large? The moon at rising or setting always seems large (the “moon illusion”), even when it is at its most distant from Earth.

For those who enjoy watching or photographing the moon’s big reddened disk coming up over distant mountains, here are moonrise times for the Coachella Valley until a week after full. Times are when the moon’s disk would just start to appear over an ideal, flat horizon. In practice, our mountainous surroundings will delay risings and hasten settings by several minutes.

Tuesday, Aug. 20: 7:05 p.m.—9 degrees south of east (full)

Wednesday, Aug. 21: 7:44 p.m.—3 degrees south of east (98 percent)

Thursday, Aug. 22: 8:21 p.m.—3 degrees north of east (94percent)

Friday, Aug. 23: 8:57 p.m.—8 degrees north of east (88 percent)

Saturday, Aug. 24: 9:34 p.m.—13 degrees north of east (80 percent)

Sunday, Aug. 25: 10:12 p.m.—17 degrees north of east (71 percent)

Monday, Aug. 26: 10:53 p.m.—21 degrees north of east (61 percent)

Tuesday, Aug. 27: 11:35 p.m.—23 degrees north of east (51 percent)

August Predawn Riches!

Up to 13 objects of first magnitude or brighter, and a meteor shower, are all visible in the early morning hours! Our all-sky chart for morning mid-twilight, below, depicts the sky about 42 minutes before sunrise in the Coachella Valley.

Jupiter is the bright morning “star.” In mid-twilight, you’ll find it about 20 degrees up in east-northeast on Aug. 1, and climbing nearly halfway from the east horizon to overhead by month’s end. Mars, of magnitude 1.6 (and not quite qualifying as first magnitude), is to the lower left of Jupiter, within 5 degrees on Aug. 1, and widening to 18 degrees by Aug. 31. Mercury on Aug. 1 is within 8 degrees to the lower left of Mars and 12 degrees to the lower left of Jupiter, but drops into bright twilight around mid-month. To Jupiter’s upper left, find bright Capella, the “Mother Goat” star, in the northeast, getting higher as month progresses. To the upper right of Jupiter is reddish Aldebaran, eye of Taurus the Bull, with the compact Pleiades star cluster or Seven Sisters (not shown), 14 degrees higher. Below Taurus, find Betelgeuse and Rigel, shoulder and foot of Orion the Hunter (with his belt, a nearly vertical line of three stars midway between them, not plotted).

The Summer Triangle of Vega-Deneb-Altair is still visible in the west to west-northwest at dawn early in August, but only Deneb remains at month’s end.

From midnight through the predawn darkness hours of Monday and Tuesday, Aug. 12 and 13, watch the annual Perseid meteor shower rise to peak. With no moon present to spoil the view, this is a very good year!

After viewing the shower, follow Orion’s belt downward as dawn brightens to watch for the rising of Sirius, the “Dog Star,” in the east-southeast. Procyon will have already risen in the east; it completes the Winter Triangle with Sirius and Betelgeuse. Try to spot Sirius before you lose sight of Altair sinking in the west, and you’ll see both the winter and summer triangles simultaneously!

If you succeed, you can tally 11 stars and two planets of first magnitude or brighter. We’ve not yet mentioned Pollux, in the east-northeast to the lower left of Jupiter (with 1.6-magnitude Castor, the other Gemini Twin, not plotted, 4 1/2 degrees above Pollux), and Fomalhaut, mouth of the Southern Fish, very low in southwest.

The waning crescent moon in the morning sky appears near the Pleiades star cluster on and Aug. 27, Aldebaran on Aug. 1 and 28, Jupiter on Aug. 3 and 31, Mars on Aug. 4 and Sept. 2, and Mercury on Aug. 5.

Robert C. Victor was a staff astronomer at the 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.

Published in Astronomy