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Last updateSun, 30 Aug 2015 2pm

Astronomy

For much of February, early risers will continue to enjoy all five bright planets before dawn, as the waning moon sweeps past all of them through Feb. 6. In its next trip around Earth, the moon will go past four planets from Feb. 24 through March 7.

February’s evening mid-twilight occurs about 40 minutes after sunset from our latitude. Sirius is the brightest object plotted on our evening chart until very late in the month, when Jupiter appears above the horizon just north of due east.

Sirius and Capella are the southern and northern vertices and brightest members of the huge Winter Hexagon, with a seventh star, Betelgeuse, inside. Regulus and Jupiter follow the Hexagon across the sky. But you needn’t wait until the month is almost over to see Regulus and Jupiter; just look later in the evening. By Feb. 18, Regulus is at opposition and visible all night—note it is shown on both charts—while Jupiter rises just after the end of twilight, some 1 1/2 hours after sunset. Jupiter will be at opposition on the night of March 7-8, as Earth passes between that planet and the sun.

After Sirius, the next-brightest star is Canopus. At the end of February, both stars climb to their highest points, due south, very soon after the end of evening twilight. From Palm Springs, Canopus at its best stands just 3 degrees above the horizon.Select a site where mountains south of you don’t block your view.

As for the aforementioned Solar System Extravaganza: Within a 12-day interval, from Jan. 27 through Feb. 6, the moon passes all the naked-eye planets in the morning sky.

To provide a chance for locals to view this unusual lineup of the moon and five planets with the unaided eye, binoculars and telescope, I will hold five predawn sky watches, if the sky is clear. The sessions will be held on the following dates: Sunday, Jan. 31; Monday, Feb. 1; Wednesday, Feb. 3; Saturday, Feb. 6; and Sunday, Feb. 7. All five watches will be held in Palm Springs, from 5:15 until 6 a.m., on the pedestrian bridge crossing over Tahquitz Creek, at Camino Real between north and south Riverside drives, three blocks north of Cahuilla Elementary School.

After posing near Jupiter on Jan. 27 and 28, and just 4 degrees north of Spica on Jan. 30, the moon continues eastward, passing four more planets Feb. 1-6,while Mercury and Venus draw closer to each other.

On Feb. 1, Mars appears within 3 degrees to the lower right of the moon, now just past last-quarter phase and just less than half full. An hour before sunrise on Feb. 1, five bright planets, Mercury-Venus-Saturn-Mars-Jupiter, in order from east-southeast to west-southwest, span 115 degrees.

On Feb. 3, Saturn appears 4 degrees below the moon. Antares appears 9 degrees to the lower right of the lunar crescent and 8 degrees to the lower right of Saturn.

On Feb. 5, Venus appears within 9 degrees to the moon’s lower left.

On Feb. 6, look for Mercury within 5 degrees to the lower left of Venus and 3 degrees to the lower right of a thin crescent moon, only 5 percent full and just more than two days before new. This morning, the five naked-eye planets span an angle of 120 degrees across our sky, one-third of the way around the circle of the zodiac.

On the morning of Feb. 7, Spaceship Earth is carrying us toward the planet Mars. Our faster-moving home planet will overtake the red planet in late May. Watch about 40-45 minutes before sunrise this morning for a last, very thin old crescent moon, about 2 percent full, just risen in the east-southeast, about 17 degrees to the lower left of Venus and 13 degrees to the lower left of Mercury. New moon, invisible near the sun, occurs on Feb. 8 at 6:39 a.m. PST.

Back to the evening sky: During Feb. 9-22, track the waxing moon at dusk, within an hour after sunset. The first crescent, only 3 percent full, will be seen very low, 10-15 degrees south of west in evening twilight, on Tuesday, Feb. 9, some 36 hours after the new moon. The moon reaches first quarter, half full, on Sunday evening, Feb. 14. An occultation of Aldebaran, eye of Taurus, will take place on the next night. Find that bright star a few degrees east of the moon at dusk on Monday, Feb. 15, and watch the moon narrow the gap until the star disappears behind the moon’s dark side at 1:05 a.m. on Feb. 16, not long before they set. From the Coachella Valley, the moon will be only 4 degrees above the horizon, so choose your viewing site with that in mind.

The waxing gibbous moon will leapfrog over a line joining Pollux and Procyon a few nights later, between the evenings of Feb. 18 and 19. Passing full, the moon will skip past Regulus, heart of Leo, the Lion, in the eastern evening sky, from Feb. 21 to 22. The moon rises some 40 minutes before sunset on the 21st, and just a quarter-hour after sunset on the 22nd. On the 23rd, the moon still rises in twilight some 70 minutes after sunset, a few degrees to the lower right of bright Jupiter. Over the next week, the moon rises 50-55 minutes later each night, and soon can no longer be viewed at a convenient early evening hour. So, back to predawn viewing!

Follow the moon Feb. 22-March 7 by shifting your viewing time back to morning twilight, about one hour before sunrise. On Feb. 22, catch Regulus just 3 degrees north (to the upper right) of the full moon in the western sky an hour before sunrise.

On Feb. 24, look for bright Jupiter about 5 degrees to the lower right of the waning gibbous moon. On Feb. 26, catch Spica 6 degrees to the moon’s lower left. As previously mentioned, on the morning of Feb. 27, six solar system bodies span 150 degrees across the sky. In order from west to east-southeast, locate Jupiter, the moon, Mars, Saturn, Venus, and possibly Mercury, just more than 6 degrees to the lower left of Venus. Binoculars can give you final views of the innermost planet before it slips into bright twilight on its way toward the far side of the sun.

Illustrations of events mentioned above appear in the Sky Calendar. For a sample issue, visit www.abramsplanetarium.org/skycalendar.

The Astronomical Society of the Desert will host a star party on Saturday, Feb. 13, at dusk at the Visitor Center of the Santa Rosa and San Jacinto Mountains National Monument. Dates of future star parties, with directions and maps to the sites and info on lectures and special events, are available at www.astrorx.org.

Robert C. Victor was a staff astronomer at Abrams Planetarium at Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs. Robert D. Miller, who provided the twilight charts and the planet orbit charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.

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