A very bright comet in our skies NOW! January 6, 2007Posted by dorigo in astronomy, internet, news, science.
A small comet found by Robert Mc Naught last August could put up quite a show during the next few days, just after sunset.
The celestial body, named after the discoverer and given the classification code C/2006 P1, will reach perihelion on January 12th, when it will be just 16 million miles away from our sun – not exactly at an arm’s reach, but indeed very close by solar system standards.
The predictions for its brightening as it approaches the sun are wildly uncertain, as often happens with these elusive and unpredictable objects. Tidal forces could break the nucleus apart, or causing sudden outbursts. Magnitude estimates at perihelion range from +2 to a whooping -8… Yes, you can still call that a prediction, although it is a range spanning four orders of magnitude. What is certain is that the comet is already a naked-eye object, at a magnitude of about 2.5 right now.
If you are confused by the above figures, let me just explain that the magnitude scale used by astronomers for the brightness of celestial objects is logarithmic: while a M=6 star is at the limit of our eye’s detection power, there just is a few dozens M=1 stars in the sky, and they shine 100 times more bright. Further 100 times more bright is Venus, typically at M=-4. A M=-8 comet would be easy to glance during daytime!
So, it is highly advisable to give a look at the south-western sky in the next few nights, just after sunset. If you manage to see bright Venus, then have a look on the right of it with a pair of binoculars. Do not expect to see much though – a comet is a diffuse object, and even if its magnitude were to equal that of Venus, you could still have a hard time locating it in the haze of the horizon. Viewing conditions will play a major role in allowing or preventing you to see anything – but a -8 object should be impossible to miss.
You can find a finder chart for the comet – rather sketchy but better than nothing – along with a more detailed description of the event at http://www.msnbc.msn.com/id/16474386/ .