Skywatch January 2017

Skywatch January 2017

Planets in January 2017  

Venus, Mars and the moon at dusk

As it’s done since August, Venus continues its role as a blazing beacon in the west sky at dusk in January; in fact, this current appearance of Venus is the planet’s best evening appearance in five years. The year starts with the lovely sight of Venus and a slender crescent moon together at dusk in the west on January 1. Look west that night starting about 6:45 p.m.; the moon will be just below the brilliant Venus, both about one-third of the way up in the west. The moon and Venus set around 9:30 p.m. on New Year’s Day.

Throughout January, Venus continues to appear about one-third of the way up in the western sky as it gets dark, and continues to set around 9:30 p.m. At the start of January, Venus shines at minus 4.34 magnitude, far brighter than any other sky dot; by the month’s end, it blazes at minus 4.5.

While the moon moves away from Venus quickly after January 1, the planet Mars hangs above Venus in the west throughout the month. In early January, Mars is about 10 degrees above Venus, which is about the width of your palm at arm’s length. At the end of the month, the apparent distance between Venus and Mars has been cut in half, to five degrees, or a little less than three fingers at arm’s length.

Mars continues to fade in brightness as the earth, on its faster track around the sun, pulls away from it. The planet hovers at first magnitude, but is about 100 times dimmer than Venus below it. Mars looks like a pale, amber-colored speck. Just as Venus sets around 9:30 p.m. all month, Mars sets at 10 p.m.

Look for the slender crescent moon next to Mars on January 2, the night after the moon visits Venus; and again on January 31.

Jupiter is the king of late night

The planet Jupiter, which has brightened the predawn skies for the last few months, rises in the east at 1:15 a.m. in early January and by 11:30 p.m. at the end of the month. The planet, which appears distinctly white, shines at minus 2 magnitude, brighter than any dot except Venus. Throughout January, look for Jupiter high in the southwest by daybreak.

Saturn is back!

Saturn rises in the east about 5:30 a.m. in early January and is about a palm’s width above the horizon at daybreak. By end of month, the ringed planet comes up at 4 a.m. and is one-third of the way up in the west at dawn. The planet shines at 0.5, as bright as a good bright star, and has a distinctive yellow-white hue. Look for a slender waning crescent moon next to Saturn early on January 24.

Mercury

For about the 10th to the end of the month, Mercury rises at 5:45 a.m., and still huddles low in the east when day breaks about 45 minutes later. It shines at 0 magnitude earlier in the month; during the last half of January, when it goes to minus 0.2, it should easier to spot in the predawn light.

Other sky events in January

The Southern Cross returns

The Southern Cross, or Crux, missing as always from our skies from July through November, has returned to our morning sky. This compact Roman Cross of a constellation rises in the south southwest at 4 a.m. in early January, and is due south at daybreak. By the end of the month Crux rises at 2 am, is due south at 4 a.m., and sets at dawn. The constellation hugs the south horizon during its five-hour passage above the south horizon in the islands.

Hawai‘i is well-placed for viewing the Quadrantid meteor shower

The Quadrantid meteor shower, the first meteor shower of 2017, happens in the hours before dawn on January 3.

The streaks of the Quadrantids shower appear to come from the constellation of Bootes the Herdsman, in the northeast. The shower’s name comes from “Quadrant Muralis,” or “Mural Quadrant” (an astronomical tool), which is a now-obsolete name for a part of the sky that now belongs to the constellation of Bootes.

The Quadrantids have a sharp, short peak, lasting only a few hours. This is in contrast to some of the other, more famous annual showers, such as the Perseids, where the shower’s peak can last for two days.

That said, given this short sharp peak, Hawai‘i is in an excellent position to catch this 2017 shower. The Quadrantid shower’s peak – that is, the time when we expect the maximum amount of asteroid debris to hit our atmosphere and burn up – is expected around 4 a.m. on January 3 Hawaii Standard Time. (In other words, stay up late on January 2, and into the very early hours of January 3.)

This is good news for us, because it means that the shower will peak in the early morning hours, which is always the ‘sweet spot’ for shooting star showers. These repeating annual showers are caused as the earth enters into debris left over from a specific comet (or, in the case of the Quadrantids, an asteroid, 2003 EH). As the earth goes around the sun, our planet runs into the same debris at the same time each year. This is why these showers occur at the same time each year. After midnight, the part of the earth that you are on is facing toward the debris that causes the meteor shower.

The final positive factor in hoping for a good shower in Hawai‘i this January 3: the moon, that great foe of meteor-viewing, will have set well before the peak of the shower on January 3.

To view the shower, scan the eastern skies; the general area between the handle of the Big Dipper is a good place to focus. Make sure you are comfortable; a lawn chair is helpful. The less light in your local sky, the better the viewing will be.

Viewing of the Quadrantids may also be good in the predawn hours of January 4; but since that short peak of the Quadrantids, your best viewing will probably be those predawn hours on January 3.

January Sky Map

Keah Watkins | Bishop Museum

Like all of our monthly maps, this one is good for 10 p.m. on the first day of the month, 9 p.m. for the middle of the month, and for 8 p.m. at the end.

Moon phases (Hawaiian Time zone):

First Quarter: January 5
Full: January 12
Third Quarter: January 19
New: January 27

2017-06-05T12:04:32+00:00 Monthly Astronomy Article|