A total lunar eclipse will take place early on Dec. 10. As seen from the islands, the moon will be in total eclipse for about 45 minutes, from 4:10 to 4:55 a.m. So, you either need to stay up late on Dec. 9 or set your alarm for very early Dec. 10.
The partial phase of the lunar eclipse will begin at about 2:45 a.m., as the moon starts to enter the deep inner shadow (umbra) of Earth. By 4:10 a.m. the eclipse will be total. The moon will be about 30 degrees above the western horizon, or about a third of the way between the horizon and the top of the sky. It should be dramatically darker and redder than usual. This total phase will last till 4:55 a.m., when the moon will start to leave the umbra, and you will see it start to lighten. By 6:20 a.m., just as the first glimmer of dawn appears, the partial phase will be over.
During a lunar eclipse, Earth gets between sun and moon. Earth’s atmosphere keeps most of the sun’s light from reaching the moon. But longer wavelengths of red light do make it through, thus the moon’s pale copper-to-deep red tone.
Half of the planet sees a lunar eclipse. The Dec. 10 eclipse also will be visible throughout virtually all of Asia and Australia, weather permitting. More information can be found at this NASA eclipse website: eclipse.gsfc.nasa.gov/eclipse.html.
Also next month, the peak of the Geminid meteor shower occurs on Dec. 13 and 14. This shower might produce up to 60 meteors an hour. Find clear skies, a fairly clear horizon and a place where you can look up comfortably. Telescopes and binoculars are not needed — just search the skies.
December planets
Venus continues to hover low in the west at dusk, a brilliant evening star. At minus-3.9 magnitude it’s the brightest thing in the evening sky next to the moon. Venus sets at about 7:30 p.m. at the start of December and around 8:30 p.m. at the end. Look for the early crescent moon next to Venus on Dec. 26.
At minus-2.7 magnitude, Jupiter is the brightest dot of light in our December evening sky once Venus sets. Look for Jupiter about halfway up in the east at dusk at the start of the month. In early December Jupiter is high overhead at 10 p.m. and sets at 4 a.m. By the end of December, Jupiter is high overhead at dusk and sets by 2 a.m. Look for the waxing gibbous moon next to Jupiter on Dec. 6.
Mars rises in the east just after midnight at the start of December and is two-thirds of the way up in the east at daybreak. By the end of December, Mars rises at 11 p.m. and is due south, very high up, at daybreak. This month Mars swells from magnitude 0.8 on Dec. 1 to magnitude 0.2 by the end of the month. Look for the third-quarter moon next to Mars on Dec. 16 and 17.
Saturn is in the morning sky. The slightly yellowish planet rises at 4 a.m. at the start of December and is about a third of the way up in the east at dawn. By the end of the month, the planet rises at 2 a.m. and is halfway up in the east at dawn. It’s quite bright at 0.7 magnitude. Look for the waning crescent moon next to Saturn early on Dec. 19.
Look for Mercury from Dec. 15 onward at about 6 a.m., about 6 degrees above the eastern horizon. Mercury shines at 0.1 on Dec. 15 and at minus 0.37 at the end of the month. Look for the waning crescent moon next to Mercury on the morning of Dec. 22.
December stars
The familiar constellations of winter have returned. Look for Orion the Hunter, rising in the east, with its familiar hourglass shape, distinctive belt of three stars, and brilliant stars Rigel and Betelgeuse. Other winter constellations in the low eastern sky include Auriga the Charioteer, with its brilliant yellow star Capella; the Gemini, marked by the twin bright stars Castor and Pollux; and Taurus the Bull, with the reddish Aldebaran marking its eye.
Very low in the west you can still see the summer triangle — December is your last chance. This triangle is made up of three bright stars from different constellations: Vega, the brightest star in the triangle, in Lyra the Harp; Altair, in Aquila the Eagle; and Deneb, the dimmest of the three, in Cygnus the Swan. We’ve shown both the individual constellations and the triangle on our map.
Looking north, the constellation of Cassiopeia if high overhead. Cassiopeia is made up of five stars that form a squished W. The three middle stars form an arrow pointing roughly to the North Star.
Happy birthday
Dec. 12 is the 50th birthday of Bishop Museum’s J. Watumull Planetarium. When it opened, the planetarium was the first public building on the museum’s campus in nearly 40 years. For the first time anywhere in Polynesia, people were able to experience a cloudless night sky in the middle of the day.
Why did the museum take such a bold leap? It might have had something to do with the space race and the desire to catch up with the Soviets in science education. It was also driven by the still-vague feeling that the stars must have been important to Polynesian navigation. In a classic case of "build it and they will come," the planetarium would go on to play a crucial role in the revival of Polynesian navigational skills in the 1970s and 1980s.
I’ll give a free talk on the structure’s history at 7 p.m. Dec. 12, in the planetarium. I’ll also give a live tour of the December night sky. Afterward we’ll use the observatory telescope, which dates to that 1961 opening, to look at Jupiter and other objects in the real night sky.
This program is free but reservations are required. Call 848-4168 or sign up at bishopmuseum.org.
Mike Shanahan is director of Education, Exhibits and Planetarium. For more information, go to www.bishopmuseum.org/planetarium/planetarium.html.