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.