October’s new moon brings us a ‘ring of fire’ solar eclipse (Image Credit: Space.com)
The new moon occurs on Saturday (Oct. 14), at 1:55 p.m. EDT (1755 GMT), according to the U.S. Naval Observatory, and this time the moon will create an annular solar eclipse visible in the southwestern U.S., Southern Mexico, Central America and northern South America, primarily in Colombia and Brazil.
New moons occur when the moon passes between the sun and Earth. About every 29.5 days, the sun and moon share the same celestial longitude, an alignment also called a conjunction. Celestial longitude is a projection of Earth’s own longitude lines on the celestial sphere — a line drawn from the North Celestial Pole, near Polaris, the Pole Star, due south toward the sun also hits the new moon. In this case, the sun and moon are lined up so that the moon passes in front of the sun, putting a part of Earth in its shadow, creating a solar eclipse.
Solar eclipses come in several varieties. There are total solar eclipses, for example, in which the moon blocks the sun entirely. Another type is an annular solar eclipse, in which the moon appears just a bit smaller than the sun; there is a ring of light around the edge of the moon. The reason for the different eclipses is that the lunar orbit is an ellipse rather than a perfect circle; the moon can be closer or farther away from us than “normal” on its passes. Though the difference is minimal, it’s enough to alter the apparent size of the moon in the sky. A big difference, visually, between annular and total eclipses is that one cannot see the solar corona (a part of the sun’s atmosphere) during an annular eclipse, because the ring of light around the moon is too bright.
An important note about observing solar eclipses: Always use proper safety equipment, and never view the sun directly through optical aids without approved solar filters. Even when the sun looks dimmed (as during sunsets or sunrises), a camera lens, low-power binoculars or spotter scope, let alone a telescope, will concentrate the light and the energy from the sun into your eye. This can cause retinal burns and permanent damage to one’s eyesight. The safest thing to do is view an eclipse through filtered glasses specifically designed for the purpose, or to project an image of the eclipse onto a large flat surface set up behind a telescope or mounted binoculars. As a general rule, if it isn’t designed specifically for solar viewing, don’t use it to look at an eclipse.
For observers in the U.S., Saturday’s eclipse will first be visible on the west coast of Oregon, near Eugene. In Eugene, the moon touches the sun’s edge at 8:05 a.m. local time. Sunrise is at 7:25 a.m., so the sun will be close to the horizon. The moon will appear to touch the “top” of the sun and pass across it as the sun gets higher in the sky. Annularity — the moment when the moon is surrounded by a ring of sunlight — begins at 9:16 a.m. and lasts for 3 minutes and 55 seconds. The eclipse ends at 10:39 a.m. local time.
The track of the moon’s shadow will move roughly southeast across the continent. As it leaves Oregon and enters Nevada, the annular eclipse will be visible in Winnemucca and Elko. In Elko, the eclipse begins at 8:07 a.m. PDT and annularity starts at 9:22 a.m., lasting for 4 minutes 18 seconds. The path then moves into Utah, just southwest of Salt Lake City; one good place to see it is Capitol Reef National Park, where the eclipse begins at 9:09 a.m. MDT. Annularity is at 10:27 a.m. MDT and lasts 4 minutes and 40 seconds.
The eclipse path also goes through the Four Corners Monument, where the borders of Colorado, Utah, Arizona and New Mexico meet. The eclipse starts there at 9:11 a.m. MDT and annularity begins at 10:30 a.m., lasting for 4 minutes and 40 seconds. In New Mexico, the eclipse will be visible in both Albuquerque and Santa Fe. In both cities, the eclipse starts at 9:13 a.m. local time. In Albuquerque, annularity begins at 10:34 a.m. and in Santa Fe it is at 10:36 a.m. Annularity is much longer in Albuquerque; 4 minutes and 48 seconds against Santa Fe’s 2 minutes and 45 seconds. The reason for the difference is Santa Fe is closer to the edge of the shadow’s path; Albuquerque is closer to the center of it.
In Texas, the eclipse will be visible in cities such as Odessa, San Antonio and Corpus Christi. In San Antonio, the eclipse starts at 10:23 a.m. local time and annularity begins at 11:52 a.m., lasting for 4 minutes and 21 seconds.
The next ports of call for the eclipse will be in Mexico, in the states of Campeche, Yucatan and Quintana Roo. In Chetumal, first contact (when the moon touches the sun) is at 10:51 a.m. local time, and annularity, which lasts for 4 minutes and 21 seconds, begins at 12:29 p.m.
Annularity will be visible across the entire northern half of Belize and in central Honduras and Nicaragua. In Costa Rica, the path of annularity grazes the Atlantic coast; the city of Limon will get 1 minute 18 seconds of annularity at 12:02 p.m. local time.
After that, the eclipse is visible in central Panama, and then Colombia. In Cali, Colombia, the eclipse starts at 11:45 a.m. local time. Annularity is at 1:31 p.m. local time and lasts for 3 minutes 40 seconds. In Brazil, the path of annularity passes through the northern half of the country, starting in the state of Amazonas and ending in Paraiba and Rio Grande do Norte. In Natal, where the eclipse track leaves Brazil’s eastern coast, the eclipse starts at 3:29 p.m. local time and annularity is at 4:43 p.m. Natal is at a point where the sun sets before the eclipse is over; sunset is at 5:13 p.m. local time, when the sun will still be partially covered by the moon.
The nighttime planets
While the solar eclipse won’t be visible everywhere on Oct. 14, the night sky planets will be. At the latitude of New York City, Chicago or Sacramento, Mars will be quite close to the horizon at sunset and lost in the solar glare in the evening. By about 8 p.m., however, Saturn will be visible in the southeast, about 32 degrees above the horizon in New York City, where sunset is at 6:17 p.m. local time on Oct. 14. The planet reaches its highest altitude of 36 degrees at about 9:37 p.m. and it sets at 2:54 a.m. Oct 15. (Your clenched fist held at arm’s length covers about 10 degrees of sky.)
Jupiter rises at 7:12 p.m. local time in New York, so the planet is visible for the entire night as it tracks across the southern half of the sky. Jupiter is at its highest point (called crossing the Meridian or transiting) at 2:06 a.m. EDT on Sunday (Oct. 15), when it gets about 63 degrees high, about two-thirds of the way from the southern horizon to the zenith. The planet sets after sunrise on Sunday at 9:01 a.m. local time.
Venus rises at 3:17 a.m. on Sunday in New York, in the constellation Leo. It will be the brightest object in the sky in the predawn hours. By sunrise at 7:06 a.m. the planet will reach an altitude of 42 degrees in the southeast; if you observe it, try to see how close to sunrise the planet remains visible.
Mercury, meanwhile, will be nearly impossible to see, as it is so close to the sun: At sunrise, the planet is no more than 3 degrees above the horizon, and the planet rises at 6:49 a.m. in New York.
For Southern Hemisphere skywatchers, the situation will differ slightly, as the sky is “reversed.” Jupiter, for example, rises at 9:29 p.m. in Santiago, Chile (and at similar times in other mid-southern latitude locations) and reaches its highest altitude at 2:54 a.m. local time on Sunday, when it is about 42 degrees high (approximately halfway to the zenith from the horizon). Saturn, which rises in the afternoon (3:45 p.m. local time in Santiago) is 68 degrees high almost due north by about 10 p.m. Venus, meanwhile, rises at 4:56 a.m. local time on Sunday in Santiago, and by sunrise (which is at 7:01 a.m.) the planet is 24 degrees high in the northwest.
Stars and constellations
From mid-northern latitudes in mid-October, the summer constellations of the zodiac — Sagittarius, Ophiuchus and Scorpio — are setting; Scorpio is mostly below the horizon and Sagittarius is low in the southwest by 7:30 p.m.; the Summer Triangle of Altair, Vega and Deneb is in the western half of the sky. Looking almost straight up, one sees Deneb, with Vega to the right if one is facing south, and Altair below both. Turning north, one will see the Big Dipper close to the horizon, the classic dipper shape appearing right side up (the bowl facing upwards), and one can use the pointers, stars named Dubhe and Merak, to find Polaris, the pole star. Polaris is the brightest star in Ursa Minor, the Little Bear, and if the sky is dark and one is away from city lights, the curve of the Little Dipper’s handle is easier to see.
If one continues the line from the Big Dipper through Polaris, one reaches Caph, or Beta Cassiopeiae. Along with four other bright stars, it forms Cassiopeia, a “W” shaped constellation. Between Cassiopeia and Ursa Minor is Cepheus, the King, and Cassiopeia’s husband. Cepheus and Cassiopeia were the legendary king and queen of Aethiopia, and Cassiopeia boasted that her daughter Andromeda was more beautiful than the sea nymphs, angering Poseidon, the god of the seas. To assuage Poseidon’s anger, Andromeda and Cepheus were forced to sacrifice their daughter Andromeda to the sea monster Cetus, but Andromeda was saved by Perseus on his winged horse Pegasus.
Early in the evening, Perseus is rising; the constellation is below Cassiopeia just above the northeastern horizon if one follows the “W” of Cassiopeia downward. Looking from the bottom of the “W” of Cassiopeia south (this will be to the right if one is observing before about 10 p.m. facing east), one encounters the two long curving lines of stars that mark Andromeda, Cassiopeia’s daughter. If one follows the stars of Andromeda up and to the right, one reaches Andromeda’s head, which is part of an asterism called the Great Square. One corner of the square is Andromeda’s head, while the other three are the wing of Pegasus.
As the night progresses and one looks below (to the east) of one corner of the Great Square, one can see Pisces, the Fishes, which are two long lines of fainter stars forming a large “V” shape, with two smaller circlets at the ends. Pisces is harder to see from urban locations, however, as the stars in it are not that bright. By 10 p.m., the constellation Cetus is above the horizon. Cetus is often depicted as a whale, and its name is related to the word cetacean, which zoologists use to describe the order of mammals that includes whales, dolphins and porpoises. Looking southward (to the right) of Cetus and closer to the southern horizon, one can see Fomalhaut, the brightest star in Piscis Austrinus, the Southern Fish. Fomalhaut is a first-magnitude star that is also one of the sun’s closest neighbors, just 25 light-years away.
In the Southern Hemisphere, sunsets are later as the austral summer approaches. In Santiago, Chile the sun sets at 7:54 p.m. local time (the new moon is at 2:55 p.m. local time). So the sky doesn’t get really dark until about 9 p.m. Observers there will see the Southern Cross low in the southwest, just underneath Hadar and Rigil Kentaurus, which one can find by following the “spar” of the cross to the north (upward from the horizon). Turning left and looking southeast, one will see Achernar, the end of Eridanus the River, about 37 degrees high. If one looks in the other direction, toward the west, one can see Antares, the heart of Scorpio (which is below the horizon in mid-northern latitudes). Scorpio is “upside down” — the claws of the Scorpion point to the horizon rather than upward, and the tail curves toward the zenith, making a fishhook shape that ends about 50 degrees above the horizon. Above Scorpio is the teapot shape of Sagittarius.
Looking north, one can see the Northern Hemisphere’s Summer Triangle, but with Altair at the top and Deneb and Vega at the bottom, close to the horizon, with Altair and Vega making a near-vertical line and Deneb being to the right (east) of them.