Newly-discovered comet is visible in daytime

If you think you need a clear night sky to see a comet, think again and mark this date on your calendar: November 28, 2013, when a recently-discovered comet will be seen briefly at daytime.

 

Dubbed ISON, the comet was discovered by Russians Vitali Nevski and Artyom Novichonok last Sept. 21, though they announced the discovery Sept. 24, Space.com reported.

 

"Comet ISON will be barely visible to the unaided eye when it is in the predawn night sky, positioned against the stars of Leo in October 2013," Space.com said.

 

Nevski and Novichonok detected the comet in photographs using a 15.7-inch reflecting telescope of the International Scientific Optical Network (ISON), near Kislovodsk.

 

Although it is more popularly known is ISON, the new comet is officially known as C/2012 S1.

 

When it was first sighted, the comet was 625 million miles (1 billion km) from Earth and 584 million miles (939 million km) from the Sun, in the dim constellation of Cancer.

 

It was shining at magnitude 18.8 on the reverse scale used by astronomers to measure the brightness of sky objects - making it about 100,000 times fainter than the dimmest star that can be seen with the naked eye.

 

Visible in broad daylight

 

But Space.com said the comet may become a dazzling object in 2013, when it reaches its perihelion (closest point to the Sun) within 800,000 milies (1.2 million km) on Nov. 28, 2013.

 

It could by then evolve into a dazzling object, which Space.com said may be "possibly bright enough to be visible for a short time in broad daylight."

 

Space.com also noted the comet's preliminary orbit bears a striking resemblance to that of the “Great Comet of 1680,” which was glimpsed in daylight and later, as it moved away from the sun, threw off a brilliantly long tail "that stretched up from the western twilight sky after sunset like a narrow searchlight beam for some 70 degrees of arc."

 

On the other hand, Space.com said the fact that the orbits are so similar seems to suggest ISON and the Great Comet of 1680 could be "related or perhaps even the same object."

 

Nearby 'landmarks'

 

On Oct. 16, 2013, the comet it will be passing very near both Mars and the bright star Regulus, which can be used as benchmarks to sighting the comet.

 

In November, it could be as bright as third-magnitude when it passes very close to the bright first-magnitude star Spica in Virgo. 

 

But it is in the few days surrounding the comet’s closest approach to the sun on Nov. 28, 2013, that may be the most interesting, Space.com said.

 

By then, the comet "will whirl rapidly around the sun in a hairpin-like curve and perhaps becomes a dazzlingly bright (negative-magnitude) object."

 

The comet will then whirl north after perihelion and become visible during December both in the evening sky after sunset and in the morning sky before sunrise.

 

"Just how bright it will be and how long the tail may get during this time frame is anybody’s guess, but there is hope that it could evolve into a memorable celestial showpiece," Space.com said.

 

Also, Space.com said this could be doubly significant for Americans, as Nov. 28 is the Thanksgiving Day holiday. — TJD, GMA News