Friday, December 13, 2013
By BERNIE REIM
February used to be the last month of the year and the word is related to rites of purification, which are februa. We are in the middle of winter but it hasn't been consistently winter-like yet.
This chart represents the sky as it appears over Maine during February. The stars are shown as they appear at 9:30 p.m. early in the month, at 8:30 p.m. at midmonth and at 7:30 p.m. at month’s end. Mars, Jupiter and Venus are shown in their midmonth positions. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom.
Sky Chart Prepared by George Ayers
There will be several interesting highlights in February, and it may not even be as cold as usual. All five of the brightest planets will be visible in the evening sky at some point, a large near-earth asteroid makes its closest approach in 37 years, and Comet Garradd should reach its brightest in Hercules.
Notice that Venus and Jupiter will keep getting closer together at the rate of almost one degree per day all month long. They will start the month 40 degrees apart, and end up just 12 degrees apart. One fist at arm's length measures 10 degrees of the sky. They will keep getting closer in March. Brilliant Venus continues to get brighter in February and sets a little later after sunset each evening. Even though it is getting less illuminated, similar to a waning gibbous moon, it is getting closer to Earth and larger in the sky. Venus is about six times brighter than Jupiter now.
The king of the planets continues to fade a little as it gets farther away, but it is still fairly bright and it will already set by 10:30 p.m. by the end of the month. You should be able to see at least two of its four large Galilean moons with just a pair of binoculars. Astronomers recently found evidence of subsurface lakes just below the crust of Europa, Jupiter's third-largest moon. One of them has the volume of all of North America's Great Lakes. They are caused by tidally warm spots in Europa's crust, which hide a deep ocean with more water than all of the oceans on Earth combined.
Mars is starting to make a real impression in the eastern evening sky. It is already rising by 8:30 p.m. in Leo starting the month, and by the end of February it will be rising by 6 p.m., right after sunset. The red planet dramatically doubled in brightness last month and will double in brightness again in February. Look for it just to the left of a nearly full moon in Leo around 8 p.m. on Feb. 9. It will reach opposition in early March, but it will not be nearly as close as it was on Aug. 27, 2003, when it reached its closest to Earth in nearly 60,000 years. You should be able to start seeing some detail in average telescopes, like dark markings and possibly an ice cap on its surface in February.
Saturn now rises by 11:30 p.m. and by the end of February will rise two hours earlier. It continues to brighten and rise earlier each evening until its opposition in mid-April. Its rings are now open at 15 degrees, which is the best angle it's had for many years.
The fifth and smallest of the brightest planets, Mercury, makes a brief appearance in the evening sky toward the end of the month. Look for our first planet low in the western sky half an hour after sunset on Feb. 22, when it will be just a few degrees to the left of a slender waxing crescent moon. Then keep looking for the crescent moon during the next four evenings as it passes right by Venus on Feb. 25 and Jupiter on the evening of the 26th. As a bonus, the moon will even pass between the Pleiades and Hyades star clusters in Taurus again on the 28th, just before it becomes a first-quarter moon the next evening.
There will also be a rare flyby of the first near-Earth asteroid ever discovered, back in 1898, named 433 Eros. It will get as bright as 8.6 magnitude in early February, but you will still need a good pair of binoculars or a telescope to see it. It already passed through Leo, just to the west of Saturn, and continues south into Hydra the sea snake through the month.
This asteroid already made history twice, and it may make history again in the distant future. When it was first discovered, it enabled an accurate measurement of the astronomical unit, using parallax, and the scale of our solar system. Then it was visited by NASA's NEAR-Shoemaker probe in 2000, which then landed on its surface on Feb. 12, 2001. This is a strange, potato-shaped, slowly rotating chunk of rock that is 21 miles long by 7 miles wide by 7 miles thick.
It is now in a safe, Mars-crossing orbit, and this time it will pass 0.18 a.u., or 70 times the moon's distance from us, its closest approach since 1975. But Eros has a 50 percent chance of having its orbit evolve into a very dangerous Earth-crossing orbit in as little as 2 million years.
If it did hit Earth then, it would cause more damage than the comet or asteroid that hit us and probably caused the extinction of the dinosaurs and most of our other species 65 million years ago.
The last major highlight, barring any new discoveries in February, will be Comet Garradd. Try to get a good look at it on Feb. 3, since it will pass right by the nice globular star cluster named M92 in Hercules that evening.
Then it will continue north through Hercules. You will need binoculars or a small telescope to see it.
Feb. 1: The waxing gibbous moon is between the Pleiades and Hyades star clusters in Taurus.
Feb. 4: Clyde Tombaugh was born on this day in 1906. He discovered Pluto just 24 years later, on Feb. 18, 1930.
Feb. 7: Full moon will be at 4:54 p.m. This is also called the Hunger, Snow or Wolf Moon.
Feb. 9-23: The zodiacal light will be visible in the western evening sky 80 minutes after sunset from dark-sky locations this month. Look for a haystack or pyramid-shaped glow of diffuse light centered on the line connecting Venus and Jupiter. This eerie, ephemeral light is caused by sunlight bouncing off tiny, individual particles of comet and asteroid dust all through the ecliptic plane of our solar system. This ring of dust is always there, but we can only catch a glimpse of it twice a year, now, and again in November about 80 minutes before sunrise in the east.
Feb. 14: Last-quarter moon is at 12:04 p.m.
Feb. 15: Galileo was born on this day in 1564. He first saw the four large moons of Jupiter, the rings of Saturn, the phases of Venus, sunspots, and many more things never seen before by any human being. He proved that the laws of nature are mathematical. The International Year of Astronomy was in 2009, celebrating the 400th anniversary of his telescope.
Feb. 19: Nicolas Copernicus was born on this day in 1473. He was a Polish priest and astronomer who said that the sun instead of the earth was actually the center of our solar system. This was later proven by Galileo, but many still did not believe it until much later.
Feb. 21: New moon will be at 5:35 p.m.
Feb. 22: Look for a very thin crescent moon just to the right of Mercury about 30 minutes after sunset this evening. You may need binoculars to spot it. And look for Venus above the pair.
Feb. 25: The moon passes just to the right of Venus this evening.
Feb. 26: The moon passes just to the right of Jupiter this evening.
Feb. 29: First-quarter moon is at 8:21 p.m.
Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.