Comet McNaught: daytime comet!

By Phil Plait | January 14, 2007 4:04 pm

Update (January 17, 2006): Welcome APODders! I see a flood of folks coming here from Astronomy Picture of the Day. Thanks for the visit. Before you click on the video below, please make sure you watch my first video (where I actually show comet footage). And you should poke around my site! I talk lots of astronomy here.

I went outside today around noon and was able to see McNaught easily with binoculars. This is truly incredible! I tried to get video (using my camera, my webcam, everything I could think of) and I simply couldn’t because the sky is too bright. But just looking through binocs it was a piece of cake. If you want to see it, GO!

But first, a mea culpa. In my last video, I made a couple of small errors, and I want to correct them. I decided to do another videoblog to do that. In it, I also describe how to find the comet.

Update: as noted in the comments below, in the video I said an eccentricity of 1 is a line, when it’s actually a parabola. I got that right in an earlier take, but messed it up in this one. Figures.

The astroblogs are buzzing about this. Asymptotia has a good post, for example. For pictures, go to, and for finding charts go to


Comments (32)

  1. Tom

    I just want to encourage you to do more of these vidcasts. Your enthusiam comes across so well in these (and to a lesser extent your writing), that it’s infectious. It makes me excited about astronomy all over again!

    Keep up the good work.

  2. Um, I believe an eccentricity of 1 results in a parabola, not a line. A line would take an eccentricity of infinity to pull off.

    (Though if you get into General Relativity, all of those orbits are straight, in a sense.)

  3. spacenaut

    Definitely visible here in SE Australia on the evening of Sunday Jan 14 through bushfire smoke haze, soon after the sunset. My son saw with unaided eyes while I needed binoculars, oh for eyes 30 years younger. The smoke haze made the sky brighter than normal, also meant no comet visible during daylight. Did get some faint fuzzy pictures of the comet & just visible on a short movie.

  4. Oh drat. I did say line, didn’t I? I can’t seem to get these videos right!

    Well, I’m not posting another correction. I’ll just addd a note to the blog.

  5. woot! good for you being able to see it. We’re having freezing rain here in New England, so no chance of seeing it day OR night.

    It didnt’ stop me from posting about comets, anyway. 😉

  6. spacewriter

    er… that should be “didn’t”…

  7. Michelle Rochon

    You really should make more videos like these! I really find it fun to have you explain the stuff on short videos, it’s really neat.

    I tried to view the comet today, but I never managed to spot it. I didn’t try with my binocs, I admit I’m a bit nervous about using these close to the sun, even if I take precautions…

  8. Supernova

    Spotted it once with my binoculars around 4 PM with the sun behind a tree. Then made the mistake of trying to find it with my naked eyes. Never found it again. ARRRGH! Oh well, at least I got a daytime glimpse.

  9. tom bendixen

    i live in southwest seattle washington i saw Comet McNaught from my apt. window on friday at 5.30 pm

  10. Chris

    Darn – it’s still cloudy here. Why does colorado have to get all this dratted winter weather.

  11. Melusine

    Another fun video. To be honest, if you made them look too polished they might lose that “I just came in from outside scruffy sweatshirt Phil at home look.” The sound works fine for me – I kind of like the raw video feel. I’d rather you do these more often than make a big production of them. Just a thought.

    Phil, what size are your binoculars? They look bigger than mine, which of course have been of no use since Houston was cloudy all day yesterday and so far rainy today. Oh well, lots of nice pictures to look at… :-(

  12. Two things.

    1. good video.
    2. now i’m upset, i tried looking for it tonight (southern hemisphere here), i just can’t see it from where i live, and if what you say is correct, i might never see it.

    Oh well, the images that are popping up over the web are fairly cool.

  13. Kaptain K

    Gravitational slingshot with a planet is not the only way to get an eccentricity greater than one.

    1) An interstellar interloper would have a substantial intrinsic velocity.

    2) a three body interaction in the Oort cloud or Kuiper belt could also result in one of the objects being on an in-bound path with substantial initial velocity.

  14. Mark Martin

    Thank goodness I’m the middle of Indiana, where it’s been raining non-stop for a couple of weeks.

  15. icemith

    Well I tried my darnest to view it but failed. Failed miserably in fact. Daytime or sunrise or sunset. But maybe I was looking too close to the sun, as others have pointed out it could be higher than I expected. Contending with cloud on the horizon is bad enough, but one does expect a result when there are no clouds in a blue sky, as here today in Sydney, Australia, but I suspect there is enough air-borne (should that be ‘sky-borne’?) material, call it ‘smog’ or just light water vapor or something that obscured the view, even with binoculars. Very carefully I might add.

    I was impressed with the links provided by others, particularly the Siding Springs Survey,

    where the comet was first noticed by Bob McNaught, and the

    site for the orbital simulation. I played with it for ages, trying everything out.

    Anyway here’s hoping for Tuesday arvo sunset, or even earlier.


  16. icemith

    Hey, I figured how to provide the URL for the link, but then forgot to do it for the second one. Oh well, here it is, hope it works.


    PS I’ll try them both myself, if I can type with my fingers crossed!

    Who said that’s what I always do? And where’s the scroll bar gone for this comments box? Oh there it is, it’s back again. What’s going on? IHS.

  17. icemith

    Voila, at least they work. Sorry for the on-line testing. Anyway I’m going to bed now. Happy.


  18. icemith

    Another oops, I’m afraid. When I typed ‘Bob’, I meant Rob (McNaught). Sorry….Why can’t I be more careful? Too many late early mornings I guess.

    I notice in the Siding Springs Survey photos, that Nasa/ANU/or whatever. funds the observatory, should supply a suitable LiLo or banana chair for more dignified, and comfortable viewing. They could even establish a ‘Chair of Daytime Cometary Research’, in honor of Rob and Gordon!


  19. Eugene

    a daytime astronomy hint… I understand you can see stars in the daytime from down a deep enough mine shaft… you might try the webcam down a long black pipe or tube. Maybe later it will clear off enough here in N. Central Texas for me to try it.
    Keep up the great job.

  20. There is more than one definition of eccentricity… in an ellipse is defined to be the ratio of the focal length to the semi-major axis. One way to achieve e=1 is to move one focus out to infinity,which generates a parabola. Another way is to set the focus length equal to the semimajor axis, which generates a line segment.

    I think both definitions are valid depending on context.

    A line is a conic section too!

  21. icemith

    Dang, another cloudy evening, so it’s still McNaught for me. The score… viewing that is. not even a hope of a glimpse. But last night I did see Venus bright and just above the crud in the sky. So I reasoned I may just, just catch that glimpse, but no. The other thing though was that the general direction from my viewing spot in the middle of Sydney, a suburban football ground, also co-incided with the glide path of most aircraft traffic from the west into the airport! At least they can be distinguished after a couple of minutes, by the tell-tale flashing wingtip lamps, even though they seem to be not moving at all. Even in binoculars.

    However I did see a very bright meteor scream across the sky – approx. SSE to NW, crossing near to the zenith, before extinguishing. Not extremely fast but quite bright. Probably covered half of the sky in its death plunge.

    So tonight it was a no-show, and I can only hope for tomorrow, and clearing skies.


  22. I just happened into your site, great so far, I,ve been going to astronomy pic/day for a couple of years now. My question to you is; first where are you? not addres, but region, New England , Florida, Colorado, Canada, that you can see the is comet during the day? I’m in New Englang just so. of Boston, and I live in a spot with enough clearing where viewing it shouldn’t be a problem,weather permitting. From my yard I,ve seen many meteor showers, and other sky junk. Thanks for the extra input and extra sites I now know of and if you could help it would be apprciated. Matt.Linde

  23. L.J. Sanchez

    Where can I see the Comet McNaught, in Hawaii before it is too late, I’ve been looking around sun set, but can’t seem to locate it.
    “ljs hawaii”

  24. Amy

    Well, I’m jealous now. It’s been a week of freezing ice/snow here in AUSTIN TEXAS of all places. No sun here. I can’t see anything in the sky.

  25. icemith

    Well it finally happened! I got to see ths McNaught Comet tonight. It was still above the crud on the horizon, about the same altitude of Venus, as had been indicated, and a handspan away. (To the left as it appears in the Southern sky). And to think I was about to go home from this vantage point, a good one as it turned out. The fact that there had been gusty winds with a promise of rain this weekend, seemed to clear some of the residual smog, so I’m glad I got to see the comet.

    However, on returning home, I could actually see the comet from my daughter’s front yard, and she lives across the street from my home. Boy, did she and the grandchildren come running! And her visiting friend and her family were facinated as well.

    Comet McNaught could be seen, and over my home! Admittedly it was in a break in the trees, but it could be easily seen, and even better viewpoints were available. Pity about the clouds and smog on the other nights.

    I was somewhat surprised to see the extent of the tail, and the brightness of the head – still not much less than Venus. I understand this will fade as it tracks further away from the Sun. Whether tommorow night’s sky will be as clear as this evening’s is another matter. I shall attempt to grab a few shots if possible.

    So here is one happy observer. And the subject was awesome.


  26. Mal

    I live in the Falkland Islands and last night we had the first clear night in about 2 weeks. Comet McNaught was more than clearly visible with the naked eye, in fact you couldn`t help but see it. Proberbly has something to with the lack of artificial light here in the Falklands. Anyway, to all those that haven`t seen it yet, keep trying, it truly is worth it.

  27. Hernan

    If I’m located at 9º North latitude do I have a chance to see this comet?

  28. uhhh okay i’ve been reading as much as I could about Comet McNaught, but nobody seems to have computed the period of its entire elliptical cycle.

    I thought a comet’s entire elliptical path and period could be computed from three seperate observations (the farthest apart the better), and there’ve been months of precise optical observations.

    So if Halley’s average period is 76.3 years, when will McNaught return to the neighborhood of Earth again? I don’t care if I’m dead when it comes back, but I just want to know if astronomers know when it’s coming back. Why the seeming reluctance to predict this?

  29. jac

    i was blown away by how bright it was, im in new south wales australia and my bf and i went for a drive threw the bush, its perfect where i live because there is all of 5 houses in the town so it was really dark,then we came to a clearing and just looked up it was so beautiful we both said at the same time CRIKEY!

  30. Faizal


    I saw the ‘Encke’ Comet at daytime on 4 of february 1994 at 5° 24.517′ N and 100° 19.733′ E.
    I think it also could be called a daytime comet.


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