SKY REPORTER: February 2012
by Steve Beyer on
Wednesday February first, sunrise is at 7:06 a.m. Eastern Standard Time. That evening the sun, located in the constellation Capricornus, sets at 5:13 p.m.
Civil twilight precedes sunrise and follows sunset by about one half hour. During darker segments of this period objects above the horizon such as the moon, bright planets, and several of the brightest stars may be seen.
At midmonth, Wednesday February 15th, sunrise is at 6:50 a.m.—sunset occurs that day at 5:30.
On the last day of the month Wednesday February 29th, the sun is in Aquarius rising at 6:30 a.m. and setting at 5:46 that evening. During January the length of time the sun is above the horizon each day increases by one hour and nine minutes.
In February average overnight temperatures recorded in Central Park rise from 24 degrees Fahrenheit on the first of the month, to 29 degrees on the 29th.
Principal Phases of the Moon are:
|Full Moon||January 7|
|Last Quarter||January 14|
|New Moon||January 21|
|First Quarter||January 29|
On Wednesday February 1st, Mercury rises just one minute before the sun, too close for viewing.
The evening sky this month features Venus, dazzling bright at visual magnitude -4.1. At the start of February it is between the constellations Aquarius and Pisces, high in the southwest during twilight, setting at 8:34 p.m. Jupiter is now in the same field of view as Venus, 40 degrees of arc east of the brighter planet on February first. Jupiter is very bright with magnitude -2.4, at the border between Pisces and Aries. The big planet sets four minutes before midnight on Wednesday the first. During February, Venus and Jupiter appear to approach each other and at month’s end are separated by just 12 degrees of arc.
This year February nights provide good opportunities to watching intriguing activity involving Galilean moons of Jupiter as well as the gradual progression of Venusian phases revealed by a telescope.
On the evening of February 1, Mars rises at 8:22 p.m. with a visual magnitude of -0.6. At the start of the month Mars is in Virgo, just east of that constellation’s border with Leo. Saturn is also in Virgo, shining with magnitude +0.6, and rises at 11:30 p.m. That night the waxing gibbous moon is in Taurus between the Pleiades and Hyades open star clusters.
Tuesday February 7 the Full Moon is situated in the constellation Leo, near first magnitude star Regulus.
Thursday February 9 the waning gibbous moon is about ten degrees south of Mars. Ten degrees of arc is equivalent to the apparent width of your fist seen with an arm fully extended.
Over the nights of Sunday and Monday February 12 and 13th, the moon is near Saturn and first magnitude star Spica in the constellation Virgo.
At nine p.m. February 15, Sirius the brightest star of night is at the meridian marking division between eastern and western parts of the sky. This line also indicates highest altitude above the horizon reached by a celestial object during its traverse from eastern to western horizon.
Sirius is an ordinary star in the midst of its period of existence. With a magnitude of -1.4. It appears bright to us not because of exceptional luminosity but because, at a distance of 8.6 light-years, it is one of the closest stars to the solar system. The Little Dog star, Procyon, is also an average star that appears quite bright with magnitude 0.4 due to its relatively close distance of 11 light years. By comparison Aludra, a supergiant star seen near Sirius in Canis Major, is extraordinarily luminous. Although it has a modest visual magnitude of just 2.5, it is remarkable that we can see it at all, because at a range of 3,200 light years from earth, Aludra is one of the most distant stars visible to unaided eyes.
Wednesday the 15th, a wide waning crescent moon is in Scorpius, near the first magnitude red supergiant star Antares. The surrounding region is one of the richest star fields in our sky.
The early morning of February 17 the lunar crescent is in Sagittarius, near a direction toward the center of the Milky Way Galaxy.
Over the course of several evenings from Friday February 24 through Tuesday the 28th, the waxing crescent moon may be seen to approach, and then pass both Venus and Jupiter. These configurations of moon and planets almost certainly catch the eye of anyone looking at the southwestern sky after sunset. Less than three degrees of arc separate moon and Venus on the evening of the 25th then Jupiter is about four degrees from the moon on the night of February 26.
The evening of February 29, Mars rises at 5:52 p.m. Venus sets at 9:31, Saturn rises at 9:37, and Jupiter sets at 10:27 p.m.
Wednesday the 29th, the First Quarter moon is in the midst of stars marking the mythical face of Taurus the Bull. This feature is represented by a "V" shaped asterism mostly formed by members of the Hyades open star cluster. First magnitude star Aldebaran marks an eye of Taurus’s face, but, at a distance from us of 65 light years, compared with about 140 light years for the center of Hyades cluster stars, Aldebaran is not a physical part of the open cluster.
Before satellite observations were able to extend accurate stellar distance measurement out to about 500 light-years from the Solar System, the Hyades served astronomers as an important link in the celestial distance scale. Observations of Hyades stars that moved through space toward an apparent vanishing point allowed estimates of their collective distances and, by extension, distances to more remote open star clusters. Historic distance estimates for the Hyades averaged about 140 light-years, a number substantially confirmed by more precise parallax determinations made since the early 1990's through use of satellite observatories such as the Hubble Space Telescope and the Hipparchos orbiting observatory.
Stars of the constellation Taurus have traditionally represented the magnificent Bull that in classical myths was a form taken by Zeus when seeking to attract lovely young Europa. In this story Europa was induced to ride on Taurus’s back. Once she was aboard, the Bull plunged into the Aegean Sea and swam off with the young woman. In keeping with this tale, the constellation figure of Taurus is represented in the sky missing its submerged parts.
Taurus is part of a stellar tableau centered on the magnificent constellation Orion, the Hunter. His figure is usually depicted with sword and shield raised against the charging Bull. Orion is accompanied by faithful dogs, represented by stars of Canis Major and Canis Minor, each highlighted by respective dog stars Sirius and Procyon.
Orion is said to have been reared as a prince in the Greek district of Boeotia. His birth had been a gift from Zeus to that realm’s previously childless king. It was a reward for hospitality extended by the king to strangers passing through his realm—actually several Olympian gods including Zeus travelling incognito.
Despite his great size, Orion is said to have been slain by an arrow from his lover Diana, goddess of the moon and hunt. Legends tell that the sun god, her brother Apollo, felt she had neglected lunar duties due to the involvement with Orion. She was tricked into unknowingly targeting the hunter to demonstrate her prowess with bow and arrow.