Getting Ready for the Comet ISON Coming this November and December

Getting Ready for the Comet ISON Coming this November and December

Hubble snaps icy Comet ISON.jpg

Some astronomers think it may be the most dramatic comet of the century.  Time will tell and so will you if you know where and when to look.


The most dramatic site in the sky for an astronomer is the appearance of a significant comet.  History records the affect of a comet in the sky from ancient times to the spectacular display of Halley's Comet in 1910.  It was easily visibly in the night sky and its tail actually crossed the path of the Earth.


Hale-Bopp was the last time we had the opportunity to view an easily visible comet in 1997.  Its appearance was also dramatic and had duration of roughly 18 months.  It was visible with the naked eye and gave many of us the opportunity to truly wonder about these remarkable celestial objects.

Comet Hale-Bopp 1995O1.jpg

 Comet Hale-Bopp by: E. Kolmhofer, H. Raab; Johannes-Kepler-Observatory, Linz, Austria

Comets sometimes appear on a regular basis as they travel across our solar system and swing by the Earth.  Halley's orbit takes it by the Earth every 76 years with its next appearance expected in 2061.  That's a long time to wait and that's why ISON is so exciting.


ISON will be visible in the eastern sky before dawn. It is predicted that it will be most visible in November and December of 2013 with its closest approach to earth on December 26th. NASA says, "It poses no impact threat to earth."  Thank you, NASA - that's always nice to know. 


Because ISON is believed to be making its first entry into our solar system the potential for a spectacular display is significant. "Having not come this way before means the comet's pristine surface has a higher probability of being laden with volatile material just spoiling for some of the sun's energy to heat it up and help it escape," NASA officials wrote in a prepared statement.


That's good news for all of us.  Many comets like Halley's have been cycling past the sun for thousands of years.  Each pass cause more of its surface material to slough off in the solar wind.  This is what causes the comet's iconic "tail," but too much sun is not good for anyone including comets.  With each succeeding pass there is less and less material.  ISON is believed to be making its first pass so hopes are high for a great show as a result of this "first occurrence." 


Unfortunately, we've all heard that before.  In 1974 the Comet Kohoutek was predicted to be a spectacular celestial event.  When it showed it was barely visible to the naked eye and became the brunt of many late-night talk-show jokes.  It's predicted to return in 75,000 years so it's probably wise to cross that one off the list.  Comet predictions are tough and the last appearance of Halley's Comet in 1986 proved that once again as it showed up as a small blip in the western sky barely visible to the naked eye. 

Comet-S74-17688 Kahoutek.jpg

 Comet Kahoutek by NASA

The best we can do is keep our fingers crossed and hope we get the grand display from ISON that some astronomers are predicting.  However, many astronomers described the same "first-occurrence" attributes to Kohoutek that they're assigning to ISON so be forewarned. 


The best way to view any comet like ISON is with the naked eye, binoculars or a telescope.  Given the length of its tail you might want to start with a smaller magnification on your scope, and increase from there as you explore the length and breadth of the object. 


Early dawn can be a tough time for viewing in November and December so remember to dress for the weather and keep your binoculars and telescope in a cold location like your garage or a shed.  This will help avoid condensation and the time before dawn can be brief so you don't want to waste any time. 


With any luck we'll forgo the scopes and simple lay back on a sleeping bag or chair and watch the show as the sun slowly rises and illuminates the tail with its long, red rays. 


And then we can all go back to bed. 

Comet ISON image at top by: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Find more on: Observing the Night Sky

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