Comet ISON: just HOW bright?

Comet Hale-Bopp over Croatia in March 1997, by Philipp Salzgeber via Wikimedia Commons

Comet Hale-Bopp over Croatia in March 1997, by Philipp Salzgeber via Wikimedia Commons

Over the New Year, I read in the Daily Telegraph that we could expect to see two comets during 2013:  the first, known as C/2011 L4*, will be visible from the UK this coming spring, if we’re lucky.   But the second, called C/2012 S1 or Comet ISON, will appear in the second half of the year and be visible in the daytime sky, dazzling us with the intensity of 15 full moons.   15 times brighter than the moon?  I know it’s the Telegraph, but are you sure?

I’ve been watching Stargazing Live! on BBC2, and last night they were talking about comets that originate in the Oort Cloud on the furthest fringes of our Solar System (wouldn’t you just love to go there?).  Many of these ethereal bodies visit the sun only once on a hyperbolic orbit before swinging off into the realms of outer space, never to be seen again.

I didn’t see the entire show, so I don’t know if they discussed the appearance of Comet ISON.  Did anyone else catch this?

Since the Daily Telegraph article was published, astronomer Stuart Clark has written a feature in the Guardian, expressing a more cautious viewpoint and calling comets ‘notoriously fickle beasts’.  Apparently there is no guarantee that we’ll see anything at all – the comet may disintegrate as it approaches the sun, like many of its over-hyped predecessors.

Does anyone else have any inter-stellar light to shed on the subject of Comet ISON?  When can we actually expect to be able to see it in the night sky, with a moderate telescope?   I know it’s probably uncool to be anything but sceptical, but can I get just a little bit excited about the prospect?  And if it really does turn out to be 15 times brighter than the full moon, has anyone thought how it might affect wildlife and nature?

Bayeaux Tapestry, depicting the 1066 Halley's Comet

Bayeaux Tapestry, depicting the 1066 Halley’s Comet; Wikimedia Commons

There have been quite a few ‘Great Comets’ throughout history.  Halley’s Comet, which is a returning comet rather than a one-off visitor, alarmed the inhabitants of the British Isles on the eve of the Norman Conquest, and it was even depicted on the Bayeaux Tapestry.   Many eye-witness accounts, including lithographs and sketches, record spectacular comets in 1680, 1744, 1843 and 1861.  When the 1861 comet was at its closest, the Earth apparently passed within its tail.

You can read the Daily Telegraph article here and the Stuart Clark’s article here.

* Named in the Telegraph as ‘2014 L4’ but after a comment (below) from Oldcat, I believe the correct name for the comet is C/2011 L4.

Great Comet of 1843 by  Mary Morton Allport, via Wikimedia Commons

Great Comet of 1843, a drawing by Mary Morton Allport, via Wikimedia Commons


  1. Well they really puffed up Comet Kohoutek back in the day and that was a bust. Halley’s was pretty dim as well.

    Why is it called 2014 anything? Isn’t the number the year of discovery?

  2. I really think they could do better coming up with names. C/2011 L4 has no romance about it, does it? I think there should be a competition to submit possible names for comets and whenever they need to name one they could pick one of their favourite submissions. A local farm tearoom up here got two new highland cows last year and asked the customers to submit names for them. My own suggestions didn’t win but someone else’s did and I like the idea of that.

    • I think that’s a great idea! I would love to have the chance to name a comet!

    • I think the reason for the unromantic name is that comets are discovered by the bushelfull these days. Most are too dim to ever make the general public take notice.

      • I see, but in that case I’d say all the more reason to have a nice long list of excellent names. Just because they’re dim doesn’t seem to me a fair reason not to give them a nice name. If my parents had thought that way I might be simply known as F/1972/Q1 (female, born in 1972, 1st quarter). 😦

      • Happy Birth-Quarter!

        A more likely scenario is that after a few years there would be articles about Death Comet Spongebob SquarePants or Comet Hello Kitty.

        Good thing you weren’t born a Roman. They had about three names for all the boys, and only one for all the girls in a Family. “Julia” meant “The Girl from the Julius Clan” and subsequent girls were numbered Julia Two and Julia Three. Boys would have the same name every generation. Firstborn one name, second born another…drives the historians crazy,

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