Skywatch February 2017

Skywatch February 2017

The planets continue to put on a good show in February 2017. The Big Dipper returns to our evening skies, as it does every winter, and the Southern Cross brightens the predawn sky.

Planets in February 2017  

Venus, Mars and the moon at dusk

February begins as January did, with the beautiful sight of a slender crescent moon together with Venus and Mars in the west at dusk on February 1. Look west that night starting about 7:00 p.m.; the moon will be about halfway up in the west, and Venus will be the brilliant white-yellow dot below the moon. Once you find Venus, look just above it for the fainter, amber-colored dot of Mars, some one hundred times dimmer than Venus. As long as you have clear western skies on February 1, this should be a lovely site from dusk till nearly 10 p.m., when Venus sets.

Through most of February, 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.; by the end of the month, it touches the horizon at 9 p.m. Venus, always blazingly bright, begins and end the month at minus 4.5 magnitude, and hits its peak brightness in the middle of the month at minus 4.62.

While the moon moves away from Venus quickly after February 1, the planet Mars hangs above Venus in the west throughout the month. In early February, Mars is about five degrees above Venus, which is less than the width of three fingers at arm’s length. At the end of the month, the apparent distance between Venus and Mars has grown to the point where Mars is twelve degrees, or the width of an entire fist at arm’s length, above Venus.

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. Mars sets at 10 p.m. in early February and 9:30 p.m. at the end.

Jupiter comes around to the evening sky

The planet Jupiter, which has brightened the predawn skies for the last couple of months, rises in the east by 11:30 p.m. in early February. Early in the month Jupiter is high in the south at 5 a.m., just before the light of dawn washes it out. By late February the King of the Planets rises in the east at 9:30 p.m., is due south at 3:15 a.m., and is working its way down the western sky when day breaks. The planet, which appears distinctly white, starts the month at minus 2.15 magnitude, and brightens to minus 2.33 by the end of February.  The only dot of the sky that’s brighter than Jupiter is Venus. At the end of February, if you want to compare the brightness of these two beacons, you’ll only have to wait 45 minutes between the time Venus sets in the west at 8:45 a.m. and the time Jupiter rises in the east at 9:30 p.m.

On the night of the 14th, look for the waning gibbous moon (that is, a moon that’s no longer full but not yet a half moon) next to Jupiter.

Saturn is back!

Saturn rises in the south southeast about 4 a.m. in early February and is one-third of the way up in the east at daybreak. By the end of the month, Saturn rises just after 2 a.m. and is halfway up in the south 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 February 20.

Since Saturn is not as brilliant as Venus or Jupiter, it does not pop out like those two planets do. A good guide this year is Scorpius the Scorpion, known here as Maui’s Fishhook; if you find that big bold constellation first, Saturn is to the left of the Scorpion.  Saturn is in fact about 15 degrees (the width of 1.5 palms) to the left of the bright, ruddy star Antares, the heart of the Scorpion.

Mercury

You might catch Mercury just at daybreak for week of February but the viewing time is brief; Mercury rises in the east at 5:50 a.m. and fades into the dawn light by 6:30 a.m. It shines brightly at minus 0.2 magnitude, but you’d need clear conditions and a dead-flat eastern horizon to spot the planet. After that, we lose the planet entirely for the rest of the month.

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 at 2 a.m. in early February, is due south at 4 a.m., and sets at dawn. By the end of the month, Crux rises at midnight, is due south at 2:30 a.m. and sets at 5 p.m. The constellation hugs the horizon during its five-hour passage above the south horizon in the islands; make sure you have a flat horizon such as the sea to view it.

Penumbral lunar eclipse but not for us, or anybody

On February 11 there is a penumbral lunar eclipse over the Atlantic. The peak time is 00:45 Universal Time on February 11. This is 2:45 p.m. on the 10th Hawaii Standard Time, which means we won’t see this penumbral eclipse for two reasons: 1): it occurs during the day in Hawai‘i when the moon is below the horizon.  2): you can’t see penumbral lunar eclipses anyway. In a penumbral eclipse, the full moon goes only into the dim, outer shadow of the earth (the penumbra), missing the deep inner shadow completely. During a penumbral eclipse, a viewer sees no change in the moon’s brightness; the outer shadow of the earth is too faint to darken the lunar disc.

If you did have superhuman, hypersensitive vision that could detect very faint changes in the lunar brightness, you would ‘see’ this penumbral lunar eclipse on February 11 from anywhere in Africa, Europe, Brazil, Quebec or Maritime Provinces.

Annular eclipse but not for us

There is an annular solar eclipse over South America and Africa on February 26; this occurs when it’s nighttime in the Hawaiian Islands and we won’t see it at all. An annular eclipse occurs when the moon is a little more distant from the earth than average in its monthly orbit around the earth; being a little more distant, the moon appears a little smaller, and is not large enough to block the entire disk of the sun, even when the moon is dead-center in the center of the sun’s disk. During an annular eclipse, a viewer with a solar filter would see a ring of sunlight appears around the moon (“annular” comes from the Latin for “ring”).

The path of the February 26 annular eclipse crosses south-central Chile and Argentina, crosses the Atlantic, and passes through Angola, northern Zambia, and southern Democratic Republic of Congo.

The time of longest duration for this annular phase (the period when the moon is entirely within the solar disc) is at 14:53 Universal Time on February 26, when the eclipse is over the south Atlantic. This is 4:53 a.m. on February 26 in Hawaii, but again we will not see this eclipse at all.

This February 26 eclipse will be as a partial solar eclipse for the southern two-thirds of the continents of South America and Africa.

By the way: every six months there is some type of solar eclipse somewhere in earth. The solar eclipse after the February 26 eclipse will be one of the great ones: on August 21 we’ll have a total eclipse of the sun that passes over the heart of the continental US, from Salem, Oregon to Charleston, South Carolina. This is the first total solar eclipse over the continental US since 1979 and, weather permitting, should be spectacular.

We won’t see a total eclipse in the Hawaiian Islands on August 21. Using a safe solar filter, a viewer in Honolulu would see the sun rise in eclipse at 6:15 a.m. on August 21. At the maximum, about 1/3rd of the sun will be covered by the moon as seen from the islands, and the moon will have uncovered the sun entirely by 7:26 a.m.

February 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: February 4
Full: Feb 11
Third Quarter: Feb 18
New: Feb 26

2017-06-05T12:04:25+00:00 Monthly Astronomy Article|