Lovejoy, Encke comets come calling

The most beautiful celestial object perceptible in the night sky is the comet. Most of the time, comets remain in deep-frozen ‘sleep’ in outer space, but occasionally they are dislodged from their orbits and fall forward in the inner solar system. Comets arriving from the depths of the solar system are still in the process of ‘waking up’ and can be disappointingly unimpressive. Comets are at their brightest when they are closest to the sun and it is best to search for them in the sky directly after sunset although never when the sun is still above the horizon.

In the months of October and November, fix your stares on the sky to watch the comets Lovejoy and Encke. They will be visible in the Northern Hemisphere throughout October and November. Lovejoy, formally designated C/2007 E2, is a non-periodic comet discovered by Terry Lovejoy on 15 March 2007. The comet reached its perihelion on September 7 2013. As of September, it remains at magnitude 8 with a short, vague tail, visible telescopically in constellation Monoceres to observers in the Northern Hemisphere. Terry Lovejoy discovered this comet on sixteen 90-second exposures obtained using a Canon 350D and a 200mm lens. The images were obtained during a comet-hunting survey that Lovejoy has been conducting for over a year. He estimated the magnitude as 9.5. Lovejoy also noted a green coma 4’ across with a strong central condensation and a slight extension toward the southwest. Comets move in elliptical orbits like the planets. But while orbits of planets are nearly circular, the ellipses are highly elongated in the case of comets with the orbit even becoming nearly parabolic.

The behaviour of comets is highly unpredictable. Comets large enough to be detected in the outer solar system may prove to have thick, insulating crusts that they never develop, whereas smaller comets may be as insubstantial as a snowball and melt away into fragments as they come closer to the sun. Comet Lovejoy had passed perihelion one month after the discovery, but was discovered about a day before its closest passage by Earth at 0.44 Astronomical Units (one Astronomical Unit = 14, 96, 00, 000 km).

Professional observatories rarely have time to devote to scan skies in search of new celestial objects, so amateur astronomers using simple equipment often discover comets. Lovejoy began October in Monoceres at a magnitude of 10 and has been getting brighter and larger since then.

Although it was lying low in September, it moved rapidly and can now be located very high in the morning sky. It can be seen below Jupiter in the morning sky, close to Gemini constellation at 4.30 am. This is a morning comet that can be clearly visible from even small telescopes.

Presently, the comet can be seen in the northern sky. Since comet Lovejoy is referred to as the ‘morning comet’, it is usually seen around 4:30 am in the southern sky. The comet is visible from all parts of India.

The night sky is clear from the moon and it is the best time to see this comet.

Another comet visible in the morning sky is comet 2P/Encke. It can be seen in the Auriga constellation around 5 am at magnitude 7. This comet was first recorded by Pierre Francois Andre Mechain in 1786, but wasn’t recognised as a periodic comet until 1819 when its orbit was computed by German astronomer Johann ranz Encke. The comet experienced one close approach to Mercury, 11 close approaches to Earth and two close approaches to Jupiter in the 20th Century.