NIGHT SKY IN DECEMBER 2009

-By Rishi Shah, President of NASO

The night skies of this month thrill sky-gazers with the beauty of planets, stars and the magnificence of various heavenly bodies that spread over the entire sky. As night descends on earth one can follow the zodiacal constellations of Capricornus (sea goat), Aquarius (water bearer), Pisces (fishes), Aries (ram), Taurus (bull), Gemini (twins) and Cancer (crab) stretching superbly across the sky from western to eastern horizon. The great square of Pegasus (winged horse) with constellation Andromeda (chained princess) that extends from its northeastern corner dominates the evening sky. Constellations Perseus (legendary hero), Auriga (charioteer) and faint Lynx (animal) are ascending the northeastern sky. Star Capella (Brahmahridhaya) sparkles in Auriga. It is barely fourty two light-years away. Lengthy watery constellations Cetus (whale) and Eridanus (river) are meandering through southeastern sky. Fascinating Orion (hunter) chased by Canis Major (great dog) and Canis Minor (small dog) are displaying their outstanding presence in eastern sky. Their prominent stars Betelgeuse (Ardra), Rigel, Sirius (Lubdhak) and Procyon (Manda) shine like exquisite gems in the sky. Constellations Cygnus (swan), Lyra (harp) and Aquila (eagle) are gliding towards western horizon with their fulgent stars Deneb, Vega (Avijit) and Altair (Sravana). Sirius belonging to a binary star system is the brightest star in the sky. It is scantly 8.6 light-years away.

Captivating planetary Ring Nebula (M57) decorates Lyra. Its reddish gaseous shroud has been expelled remarkably from dying sun-like star still dwelling at its centre. It is sheer two thousand light-years away. Enticingly strange spiral galaxy NGC918 has been located recently in Aries where arcane illumination has affirmed the existence of supernova SN2009js (massive star’s death explosion). It is sixty million light-years away. Engrossing open star cluster the Pleiades (M45) alias the Seven Sisters (Kritika) embellishes Taurus. It houses over three thousand stars surrounded by stunning blue reflection nebula and is solely four hundred light-years away. Circumpolar constellations Draco (dragon), Cepheus (king), Cassiopeia (queen) and Ursa Major (great bear) are circling around Pole Star Polaris (Dhruba Tara) that stays comfortably in Ursa Minor (little bear). Our galaxy the Milky Way runs mainly through Monoceros (unicorn), Auriga, Cassiopeia, Cygnus, and Aquila.

Elusive planet Mercury appears in western sky after sundown. It is drifting through Sagittarius (archer). Ruddy Mars glows in eastern sky late at night in Leo (lion). The mighty Jupiter coruscates in western sky among the dim stars of Capricornus. Far-flung bluish planet Neptune gleams in its vicinity. Distant planet Uranus could be discerned in barren southwestern sky between the circlet asterism of Pisces and eastern side of Aquarius. Ringed planet Saturn glints in eastern sky before sunup in Virgo (maiden). Giant star Spica (Chitra) is glistening charmingly below Saturn. Planet Venus remains out of sight this month. It is lost in solar glare, as it dashes towards Sagittarius. Diminutive dwarf planet Pluto is resting above Sagittarius. Asteroid Melpomene (18) is racing through Cetus. Comet C/2007Q3 (Sliding Spring) is tumbling through indistinct constellation Coma Berenices (Bernice’s hair) that floats above Virgo. Geminid meteor shower could produce 60/100 multi-colured meteors per hour at their peak on 13 to 14 December. They emanate from their radiant that lies above lurid star Castor (Kasturi) in Gemini and could be best watched in eastern sky after midnight till early morning. Geminids’ progenitor is considered to be asteroid 3200-Phaethon, which is believed to be the remnant of queerly extinct comet. Another Meteor shower Ursids could exhibit its maximum before dawn on 22 December, as the sporadic shooting stars emerge from the area close to star Kochab in Ursa Minor.

A minor partial lunar eclipse could be enjoyed from 23 hours on 31 December 2009 to 03:15 hours on 01 January 2010 (New Year’s Day) from our country and from different places in Asia, Australia, Europe and Africa. During the greatest mid-eclipse at fairly 01:07 hours just the dinky portion of southern limb of moon (merely eight percent of moon) would immerse in the deep shadow. Two full moons that are popularly known as long night moon or Yomari Purnae and the rare blue moon can be marveled on 02 and 31 December (the last day of 2009) respectively, while new moon is on 16 December. The winter solstice is experienced on 21 December with the shortest day and longest night in Northern Hemisphere. Christmas Day is celebrated on 25 December.

Two subsequent full moons are generally separated by circa 29.5 days and roughly 30.5 days are contained in one month. Even though it is oddly unlikely that two full moons would occur in a month, they happen regularly. The unconventional blue moon that would be seen statistically once every two-and-a-half years is prevailingly defined as the uncommon second full moon that falls in one calendar month. Over the next 50 years there will be about twenty blue moons that are randomly distributed over the years spanning from 2010 to 2060.

New Earth-orbiting Solar Dynamics Observatory (SDO) that would study and investigate Sun’s atmosphere and its functionality for five years is scheduled for lift-off soon. It would attempt to unveil the secrets of solar magnetic field inside Sun that determines the increase and decrease of solar cycles, sunspots with their eleven year rhythm, solar storms, coronal loops and ejection of solar particles and flares that disturb satellites, endanger astronauts in space and damage electrical grid on earth along with other diverse solar influences. During 1645 and 1715 the interval that became known as Maunder Minimum sunspots were hardly noticed and Europe and North America were both exposed bafflingly to bitter cold winters. It also coincided with the middle and coldest part of so-called Little Ice Age. Sun is presently in lull period and its next intense vigour is expected in 2013. The puzzling nexus between levels of Sun’s vehemence and alternation of earth’s climate would be analyzed and hopefully unraveled by SDO. The accompanying star map approximately describes the night sky over Kathmandu at about twenty hour local time during mid-December 2009.

Source: The Rising Nepal, Englsih National Daily,December 1,2009