01/30/2012
February Skies

By Dick Cookman

Highlights: Comet Journal, Martian Landers, Meteor Showers, Fat Tuesday, Leap Day, Planet Plotting, February Moon

Focus Constellations: Cassiopeia, Cepheus, Draco, Ursa Minor, Ursa Major, Lynx, Cancer, Gemini, Orion, Auriga, Taurus, Camelopardalis, Perseus

Comet Journal

Sun-grazing Comet C/2011 W3 (Lovejoy) survived passage through the atmosphere of the Sun and emerged as a major comet. After Christmas it retreated far from the Sun and has now decreased to magnitude +14.0.

Sixth magnitude Comet C/2009 P1 (Garradd) is in northern Hercules and will pass by the globular cluster M-92 on February 3rd. It will move into Draco in mid-February as it orbits above the solar system. It passed above the Sun (perihelion) on December 23rd and is expected be closest to Earth when it passes above our orbit on March 5, 2012 possibly reaching maximum brightness. It will then slowly dim in the Spring as it travels outward in the Solar System.

Martian Landers

Opportunity discovered a site where it will be well positioned for survival of the Martian winter. Since it is exploring a region which is closer to the equator than that of its cohort Spirit, orientation toward the Sun was not a factor in previous winters. However the dust buildup on its solar panels currently requires that they are positioned so as to maximize solar gain. The rover achieved a northward tilt of 15 degrees at a site called Greeley Haven in honor of a recently deceased team member, planetary geologist Ronald Greeley. The site is on the north end of Cape York on the western rim of Endeavor Crater.

The Martian winter solstice is on March 30, 2012 when the sun will be at its lowest altitude in the northern sky. The rover will be favorably positioned to continue with its winter science projects, including analysis of the nature of the nature of the core of Mars.

This radio Doppler tracking experiment seeks to measure tiny wobbles in the rotation of Mars known as precession and nutation. These result from gravitational effects of nearby planetary bodies, moons, and asteroids and can be influenced by variations in the planet's interior. The study requires many weeks of radio-tracking the motion of a point on the surface of Mars to measure changes in the spin axis of the planet. The rover's immobility during winter provides an ideal opportunity for this type of study.

Other projects to be completed this winter include preparation of a mosaic panorama of Greeley Haven and detailed investigation of the nearby rock outcrop.

Meteor Showers

Meteor Showers in February are limited to the Alpha Centaurids of the southern hemisphere on the 8th as there are none of significance in the northern hemisphere. In contrast the Quadrantid Shower of early January was quite spectacular for some observers with meteor counts approaching 150 per hour in some localities.

Fat Tuesday

Ash Wednesday is the beginning of Lent, the lengthy fast recognizing that of Moses, Elijah, and Jesus. The day preceding Lent is celebrated as Marti Gras (which is French for Fat Tuesday), a day devoted to eating extra rich foods in preparation for Lent.

The 40 days of Lent end on the day before Easter which is celebrated on the first Sunday following the first full moon following the Spring Equinox. Since the first full moon after the Spring Equinox on Mar. 20th is on Friday, April 6th, Easter Sunday is on the 8th and Good Friday is on the day of the Full Moon. Counting back 40 days (excluding Sundays but including leap day), Ash Wednesday is on February 22nd making Fat Tuesday fall on the 21st. Oh what a tangled web we weave.

Leap Day

Since it takes the Earth 365+ days to circuit the Sun, the Gregorian calendar includes 365 days in a year and 366 days every 4 years so that the calendar is synchronous with the Sun and we don't eventually end up with New Years Day in July.

Staying synchronous also requires that leap day is added in all years divisible by 4 except for those divisible by 400. The result is that 97 leap days are added every 400 years and we end up with 365+97/400 (365.2425) days per year.

Planet Plotting

Venus and Jupiter provide spectacular evening apparitions in February. One hour after sunset on the 1st Jupiter (-2.3) is high in the south southwest in Aries while Venus (-4.1) is 25° above the western horizon in Pisces. Jupiter sets two hours after Venus on the 1st and each succeeding night Venus gets brighter and sets 2 minutes later, closing the gap with Jupiter. By month's end they will be spaced 10° apart and Jupiter(-2.2) will set an hour after Venus(-4.3). February closes with beautiful pairings of the waxing crescent Moon with Venus on the 25th and Jupiter on the 27th.

During the first week of the month blue-green Uranus(+5.9) can be spotted with binoculars to the left of Venus. On the 9th, Venus passes less than 1° above Uranus which will be to the right of Venus for the rest of the month but will be hard to find in the glow of sunset.

Two weeks after superior conjunction with the Sun on the 7th, Mercury(-1.2) in Aquarius appears just above the horizon below Venus. It will dim slightly as it rises higher in the sky after sunset during the balance of the month.

Neptune (+7.9) sets just after the Sun in early February and with Mercury in the middle of the month. It is then is lost in the glow of sunset as it reaches conjunction with the Sun on the 19th.

Mars moves from Virgo into Leo on the 3rd and almost doubles in brightness in February. It rises about 9PM EST in early February and just after sunset on the 29th when it will be visible throughout the night. It will be at its brightest for 2012 at opposition on March 3rd when it is lined up with the Sun and Earth and makes its closest approach of the year.

The proximity of Mars at opposition varies through time depending on distances of each planet from the Sun. In March, 2012 Mars is close to aphelion when solar distance is greatest. Earth passed through perihelion in January and will be closer than average in early March. The resulting 2012 opposition distance to Mars is about as large as it gets. In contrast, that of 2003 was one of the closest when Mars was almost 5 times brighter. It achieved a magnitude of -2.9 (compare to -1.2 for 2012) and appeared over 3 times bigger with a width of 25.06 arc seconds (compare to 13.9 in 2012).

Saturn(+0.6) rises in Virgo rises about midnight in early February and 2 hours earlier at month's end. It brightens to magnitude +0.4 during the month and presents a good view of its rings which now tilt at about 15° to our line of sight.

Planet	Constellation	Magnitude	Planet Passages
Sun	Capricornus, Aquarius	-26.8
Mercury	Capricornus, Aquarius, Pisces	-1.1 to -1.9 to -0.9	Superior Conjunction, 2/7, 4AM EST Neptune, 1.2°NNW, 2/14, 2AM EST
Venus	Pisces	-4.1 to -4.3	Uranus, 0.31°SSE, 2/9, 8PM EST
Mars	Virgo, Leo	-0.6 to -1.25
Jupiter	Aries	-2.3 to -2.2
Saturn	Virgo	+0.6 to +0.4
Uranus	Pisces	+5.9	Venus, 0.31°NNW, 2/9, 8PM EST
Neptune	Aquarius	+8.0	Solar Conjunction, 2/19, 4PM EST Mercury, 1.2°SSE, 2/14, 2AM EST

February Moon

The New Moon of January 23rd at 2:39AM EST marked the start of Lunation #1102 which lasts for 29.62 days until New Moon at 5:36PM EST on February 21st. The Full Moon of lunation 1102 is in Cancer at 4:54PM EST on the 7th.

February's Full Moon is the "Wolf, Snow or Hunger Moon". Colonial Americans called it the "Trapper's Moon" and the Celts thought of it as the "Moon of Ice". Medieval English called it the "Storm Moon" and the Chinese refer to it as the "Budding Moon". For the Anishnaabe (Chippewa and Ojibwe) of northern Michigan it is “Namebini-giizis" (Sucker Moon).

At Lunar apogee on January 30th at 1PM EST the Moon was at the farpoint of its orbit at 251,104 miles or 63.39 Earth radii). On February 11th at 1PM EST, it will be closest to Earth at perigee (228,525 miles or 57.69 Earth radii). Another apogee occurs on February 27th at 9AM EST when it is at 251,421 miles or 63.47 Earth radii.

Planet	Constellation	Magnitude	Moon Passage	Moon Phase/Age
Sun	Aquarius	-26.8	5:36PM EST. 2/21	New ~ 0 days
Mercury	Aquarius	-1.2	5.6°SSW, 8PM EST, 2/23	Waxing Crescent ~ 2.10 days
Venus	Pisces	-4.3	3.2°S, 4PM EST, 2/25	Waxing Crescent ~ 3.93 days
Mars	Leo	-0.8	9.0°NNE, 11PM EST, 2/9	Waning Gibbous ~ 17.85 days Jupiter
	Aries	-2.2	3.8°SSE, 10PM EST, 2/27	Waxing Crescent ~ 6.18 days
Saturn	Virgo	+0.5	6.0°NNE, 5PM EST, 2/12	Waning Gibbous ~ 20.60 days
Uranus	Pisces	+5.9	5.3°SSE, 3AM EST, 2/24	Waxing Crescent ~ 2.39 days
Neptune	Aquarius	+8.0	5.6°SSE. 8PM EST, 2/21	Waxing Crescent ~ 0.10 days