December is a time of returns in the skies. Venus, Saturn and Mercury reappear; the Geminid meteor shower — one of the year’s most reliable — comes back in the middle of December; and the Southern Cross makes its return to Hawaii’s predawn sky.
December Planets
Venus, lost in the light of the sun for the last three months, emerges in the west at dusk as an evening "star." From the middle of December onward look southwest at sunset (5:50 p.m.) and search the sky just above where the sun went down. Venus should emerge by about 6:20 p.m. as a brilliant light about 5 degrees (less than the width of three fingers held at arm’s length) above the west horizon. Mid-month, Venus sets by 6:45 p.m. so you have a narrow window to catch it, but its brilliance should make it pop. By Dec. 31 Venus will be 10 degrees above the horizon at dusk (the width of your palm at arm’s length) and will not set until 7:10 p.m.
Mercury is missing for most of December, but by the end of the month Mercury can be found very low in the west at dusk, just below the brighter Venus. On New Year’s Eve, for example, look west around 6:30 p.m. and find the blazing light of Venus. Three degrees below it (less than the width of two fingers at arm’s length) is Mercury.
By Dec. 7 or so, you should be able to catch Saturn rising in the south-southeast in the moments before dawn. Saturn, which has been missing from our skies for about five weeks, rises in early December around 5:40 a.m. and is only a few degrees above the horizon by daybreak. Saturn shines at 0.55 magnitude, as bright as a bright star, and glows whitish-yellow. By the end of December Saturn-hunting should be easy; the planet rises at 4:15 a.m. and is nearly a third of the way up in the southeast when day breaks two hours later. Just before daybreak in late December, look 10 degrees below Saturn for the distinct orange glow of the star Antares, somewhat fainter than Saturn.
Look for a slender crescent moon next to Saturn early on Dec. 19.
Mars remains present, if faint, in the early evening skies for the entire month of December. For the entire month, look for Mars about a third of the way up in the southwest at dusk. It has that distinctive pale orange glow. Mars will set just around 9 p.m. all month.
On Christmas Eve, look for a slender crescent moon just to the right of Mars.
Look for bright Jupiter rising in the east around
11 p.m. in early December; the planet will be high overhead by 5:30 a.m. At the end of the month, the king of the planets rises at 9 p.m., crosses high overhead at 3:30 a.m., and is halfway down the western sky at dawn. Jupiter is brilliant, starting the month at minus 2.25 magnitude and soaring to minus 2.44 by Dec. 31. Look for the gibbous moon next to Jupiter early on the mornings of Dec. 11 and 12.
Space station pass
There are two very bright appearances of the International Space Station:
>> The space station will appear as a brilliant dot halfway up in the west-northwest at 5:34 a.m. Tuesday. As it first appears, the ISS will already be shining brighter than any star. The station will cross high overhead, just south of Jupiter, at 5:35 a.m.; it hits its maximum brightness around this time, minus 3.4 magnitude. The ISS will then pass to the southeast, vanishing at 5:38.
>> The station will appear low in the southwest at 6:49 p.m. Thursday, cross overhead at 6:52 p.m., then vanish in the northeast at 6:53 p.m.
As with any satellite appearance, it’s a good idea to check the schedule on the day of, in case changes in the ISS’ orbit have thrown off the predictions. Go to www.heavens-above.com.
Meteor Shower
The reliable Geminid shower peaks on the nights of Dec. 12-13 and Dec. 13-14. This is one of the best showers, and we in Hawaii often have good weather in December to see it, though the waning gibbous moon will provide some interference this year since it’s in the sky at the same time the shower reaches its peak.
Meteor showers are named for the constellation where the meteors appear to come from; the Geminid showers seem to come from the Gemini constellation, which is high in the east by 12:30 a.m. in mid-December. The Gemini constellation is to the left of the famous Orion constellation.
Prime viewing is 12:01 a.m. to dawn early on the 13th, and from 12:01 a.m. to dawn early on the 14th. To view this shooting star shower, just find a dark location (as little city light as possible), get comfortable (a lawn chair is a good idea), and look up.
Winter begins
Winter starts at 1:04 p.m. Hawaii Standard Time on Dec. 21. This is the shortest day of the year in the northern hemisphere.
Starry returns
The Southern Cross (official name: Crux) comes back every year to Hawaii’s skies in December. In early December, look to the south-southeast around 6 a.m. (you’ll be looking a little bit to the east of due south). Crux will clear the horizon by 5:45 a.m., giving you a mere 15 minutes to catch it before day breaks. By the end of December your odds of seeing the cross in the predawn sky improve significantly; the cross rises at 3:45 a.m. and is due south at 6 a.m. as day breaks.
The Big Dipper, missing in our evening skies in early fall, also shines in the December morning sky. The Dipper is entirely up by 2 a.m. in early December.
ENLARGE CHART
Mike Shanahan is director of Visitor Experience and Planetarium. For more information, go to www.bishopmuseum.org/planetarium/planetarium.html.