Tuesday, September 1, 2009

Night Sky In September

-By Rishi Shah

The night skies of this month display numerous planets, countless stars and various arcane celestial entities that decorate the heavens enticingly. As darkness descends on earth, the zodiacal constellations of Virgo (maiden), Libra (scales), Scorpius (scorpion), Sagittarius (archer), Capricornus (sea goat) and Aquarius (water bearer) are seen sprawling across the sky from western to eastern horizon. Kite-resembling constellation Bootes (herdsman) dominates the evening sky with its alluring star Arcturus (Swati) that is barely thirty seven light-years away. Semi-circled constellation Corona Borealis (Northern Crown) and keystone-patterned Hercules (legendary strong man) are floating to its east. Petite constellations Canes Venatici (hunting dogs) and Coma Berenices (Berenices’ hair) are slipping towards western horizon. Constellations Cygnus (swan), Lyra (harp) and Aquila (eagle) are soaring magnificently in eastern sky. Their coruscating stars Deneb, Vega (Avijit) and Altair (Saravana) sketch the bewitchingly imaginary Summer Triangle in the sky. The circumpolar constellations Cepheus (king), Cassiopeia (queen), Ursa Major (great bear) and Draco (dragon) are circling Polaris, the Pole Star (Dhruba Tara) that resides cozily in Ursa Minor (little bear). It is modestly 431 light-years away. Our galaxy the Milky Way runs amazingly through Cassiopeia, Lacerta (lizard), Cygnus, Aquila, Sagittarius and Scorpius.

Aquatic constellations Eridanus (mythological river), Cetus (whale) and Piscis Austrinus (southern fish) are unfurling across the southern sky. Their exquisite stars Mira the wonderful and Fomalhaut (Yamya Matsa) are twinkling charmingly. They are moderately 130 and 23 light-years away respectively. The awesome constellation Orion (hunter) with all its eye-catching stars like Betelgeuse (Adra) and Rigel enters the eastern sky before daybreak. It heralds the approach of winter provocatively.

Diffusely red glowing emission nebulae, blue absorption and murky absorption nebulae inhabit the captivating star cradle in NGC6559, which are five thousand light-years away in Sagittarius. Light from neighbouring stars ionizes hydrogen and protons in interstellar medium, where electrons recombine to radiate light in different hues. Minute dust particles that reflect blue light effectively to create bluish nebulosity absorbs visible light to forge inky clouds and eerie filaments. After stars explode with vehemence of unknown magnitude (supernovae) they leave behind questionably intriguing morass from where the scintillating nascent stars are born. They radiate energy copiously again. Such process of stellar evolution needs millions of years to complete one cycle.

As elusive planet Mercury drifts into the morning sky, it is rushing across the vast celestial expanse occupied by Leo and Virgo. It gleams delightfully below Venus. Resplendent planet Venus is wandering conspicuously around the region lying towards south from the famed Beehive star cluster (M44) in eastern sky before dawn. Ruddy planet Mars climbs the eastern sky late at night. It is glistening among the stars like Castor (Kasturi) and Pollux (Punarvasu) in Gemini. Mighty planet Jupiter is shining stunningly after sundown in eastern sky at the eastern side of Capricornus. Ringed planet Saturn can be discerned with difficulty in eastern sky in Leo, as it is basking in solar glare. It is gleaming roughly at the middle of an inclined line that joins two enchanting stars Spica (Chitra) in Virgo and Regulus (Magha) in Leo. Blue planet Neptune can be admired in Jupiter’s vicinity in Capricornus. Greenish planet Uranus arrives at opposition with Sun on 17 September. It stands in the barren area that unrolls southwards from Pisces’ circlet-asterism towards the boarder of Aquarius. Its entrancing sight can be relished patiently through good telescopes, as it is placed at the most advantageous point for observation. It rises as Sun sets and sets at sunrise on the next day. It is closest to earth at a distance of 2856 million kilometers, as earth, Sun and Uranus are lying almost in a straight line. Far-flung Uranus is astoundingly 3007 million kilometers from Sun. Light requires merely over two hours fourty minutes to reach earth. Distant diminutive dwarf planet Pluto is relaxing quietly in Sagittarius.

Meteor shower Alpha Aurigids peaks excitingly on the first of September in eastern sky before sunup. Their fascinating flashes of shooting stars emanate from the relatively empty zone lying south of the luminous star Capella (Brahmahridhaya) in Auriga (charioteer). Capella is sparsely fourty two light-years away. Epsilon Aurigae is one of the strangest eclipsing variable stars-system that is bizarrely housed in Auriga. One star is eclipsed by another when two orbiting stars periodically block each other’s light as the star passes in front of the other. In the extraordinary case of Epsilon Aurigae, the eclipsing object presumably appears to be gigantic elongated massive opaque disk with stars at its center. Their critical mass keeps the total discus intact and hinders it from fragmenting apart.

Asteroids Juno-3 and Melpomene-18 are dashing gracefully across Pisces and Cetus. Comet 22P/Kopff hurtles across Aquarius. Comet-hunters could thrillingly watch its movement with good optical aid during midnight in southwestern sky. It was discovered by German astronomer August Kopff in 1906. Its orbital period is estimated to be circa 6.4 years. Autumnal Equinox is witnessed on 22 September at about 21 hours Universal Coordinated Time (UTC). The duration of day and night is per se equal worldwide on this day. Full moon (popularly called ravishing harvest moon) falls on 04 September, while new moon occurs on 18 September. Indra Jatra is joyfully enjoyed on 03 September. Ghatas Thapana that ushers the glorious advent of Dashain festival is marked on 19 September. Venerated Bijaya Dashami is celebrated respectfully on 28 September.

( This article was published in The Rising Nepal,National English Daily,on Tuesday, 1 September,2009)

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