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This is the Griffith Observatory Sky Report through February 15th, 2017. Here’s what’s happening in the skies of southern California.
When the full moon rises at 5:33 p.m. on Friday the 10th, a careful look might reveal that the top edge of the moon’s disk looks is slightly dimmed. This is because the moon will be moving out of a penumbral eclipse. A penumbral lunar eclipse is the passage of the moon through the fuzzy outer portion of Earth’s shadow. The maximum of the eclipse is at 4:43 p.m., PST, or 50 minutes before moonrise. Even though the alignment that causes the eclipse is not over until 6:55 p.m., the penumbral eclipse is so subtle that any visible evidence that an eclipse is in progress will disappear sometime between 5:30 and 6:00 p.m., returning the otherwise average full moon to its normal appearance. At Griffith Observatory, the distant mountains on the horizon to the east-northeast will delay moonrise until about 5:39 p.m.
The moon lights most of the nighttime hours through the 15th as its phase changes from waxing gibbous to waning gibbous. After the full moon on the 10th, the moon rises after sunset by an additional hour each following night, so by the 15th moonrise is at 10:25 p.m.
The increasing period of moon-free sky starting on the 13th will allow early evening observers to look for comet 45P/Honda-Mrkos-Pajdusakova. Even from dark skies, as can be found at Joshua Tree National Monument, the comet may be too faint and diffuse to see by using ordinary binoculars. The brightness of the comet is reported to be magnitude 7.4, less than half as bright as some early forecasts projected. The comet will appear in the constellation Hercules until the 10th, and then it crosses Corona Borealis the Northern Crown through the 13th before it enters Boötes the Herdsman. The comet’s closest approach to Earth is during the night of the 10th, when the comet will be 7.4 million miles away. Unfortunately, the close approach coincides with the full moon, rendering the comet nearly unobservable when it is closest to us. Sky and Telescope Magazine’s website has detailed information and finder charts covering the comet’s visit.
The brightest planet, Venus, blazes in the western sky at sunset. Nearly any telescope can reveal the crescent phase of Venus. As the sky darkens, the planet Mars becomes visible as an orange dot to the upper left of Venus. Venus sets at about 9:00 p.m.
The brightest night time star, Sirius, of the constellation Canis Major the Large Dog, is highest in the southern sky when it crosses the meridian at about 9:00 p.m. Canis Major is a companion to Orion the Hunter. Orion’s belt is marked by a distinctive line of three evenly space stars, and it is is located 25 degrees to the upper right of Sirius in the early evening. Extending that imaginary line from Sirius by an equal amount past Orion’s belt, to the upper right of Orion, will bring you to the orange star Aldebaran, the fiery eye of the constellation Taurus the Bull, Orion’s mythological foe.
The second brightest planet, Jupiter, appears slightly brighter than Sirius after the planet rises in the east at about 10:00 p.m. Jupiter is in the constellation Virgo the Maiden, and is close to Virgo’s bright star Spica. Jupiter reaches its highest point in the south at 4:00 a.m.
The planet Saturn is best seen when dawn starts, at 5:20 a.m. Saturn is then 20 degrees above the southeast horizon, and appears bright, star like and golden in the constellation Ophiuchus the Serpent Bearer. Use a telescope to see the planet’s beautiful rings.
Free views of the Sun during the day and of the moon, planets, and other celestial objects at night are available to the public in clear weather through Griffith Observatory’s telescopes from Tuesday through Sunday, before 9:30 p.m. Check our website for the schedule. The next free public star party on the grounds of Griffith Observatory, hosted by the Los Angeles Astronomical Society, the Sidewalk Astronomers, and the Planetary Society, will take place on Saturday, March 4th.
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From Griffith Observatory, I’m Anthony Cook, and I can be reached at griffithobserver@gmail.com.