How To Get The Best Views Of Comet Panstarrs This March

Comet C/2011 L4 PANSTARRS with its dusty tail photographed on January 27, 2013 from Australia, where it’s well placed for viewing before dawn. Taken with an 11-inch telescope. Credit: Michael Mattiazzo

Even if Comet L4 PANSTARRS doesn’t become the spectacle many of us hope it will be, it will almost certainly be visible with the naked eye and a fine sight in binoculars, with a sweeping tail pointing away from the sun.

The latest predictions by knowledgeable amateur comet observers peg it at between magnitude 2 and 3 when far enough from the glare of the sun to see. That compares well with the brightness of the stars in the Big Dipper. Not too shabby as comets go.

Comet PANSTARRS won’t make its first appearance for northern hemisphere skywatchers until the first week of March during evening twilight. That’s only 5 weeks from now. For the U.S. the comet will appear in the western sky very near the horizon. Observers in the southern states will have a slightly better view with the comet standing a degree or two higher through the 12th; after that all locations across the country will be equally blessed. If you want to see it from the start when the comet’s also brightest, you’ll need an observing spot with a view as far down to the western horizon as possible.

Look for an observing site with a wide view down to the horizon to ensure a good view of Comet L4 PANSTARRS. Photos: Bob King

Scout your neighborhood or take a drive away from home to a nearby soccer field, park or other place with an open view to the west. Once you’ve found your ideal location, go out on the next clear, moonless night and scan that direction for city light pollution. Unless you live in the countryside, a small amount of city glow is inevitable. That’s OK. Few places are light-pollution free these days.

But if your western sky is filled with a star-swamping, foggy miasma on what is otherwise a dark, clear night, consider putting another 10, 15 or 20 miles between you and your town for a better view. If you need help finding a good site or need additional expertise, contact your local astronomy club. Here’s a directory of clubs across the U.S.

Comet L4 PANSTARRS keeps low to the horizon when its brightest from early to mid-March. The map shows the comet’s position and approximate tail direction each night from March 7-25 about 30 minutes after sunset from the mid-section of the U.S. (around latitude 42 degrees N). Created with Chris Marriott’s SkyMap software

Because of L4 PANSTARRS’s low altitude during the first half of March, light pollution, natural horizon haze and twilight itself will compromise the view. From first appearance near the sun in the west-southwest around March 7, the comet never gets higher than about 10 degrees (one fist held at arm’s length) between March 8-20, the time during which it’s expected to put on the best show. While the bright head of the comet will still be visible, much of its tail could well be masked by city light or haze. A dark site is best.

Later, as the comet moves northward and higher, it will fade but may become easier to see as it moves into a dark sky. Binoculars should show it through early May and perhaps even later. From mid-May onward, L4 PANSTARRS becomes circumpolar for observers at mid-northern latitudes and remains visible all night long. At that time it will shine around 8th magnitude and require a small to medium-sized telescope to view.

Comet L4 PANSTARRS reaches perihelion (closest to the sun) on March 10 at a distance of 27.9 million miles or about 6 million miles closer to the sun than Mercury is on average. Intense solar heating will cause the comet to grow a fine dust tail that could stretch for many degrees away from the sun. Closest approach to Earth happens on March 5 at 102.3 million miles – hardly a close shave but good enough for a nice show.

8×40 (left) and 10×50 binoculars are excellent for bright comet viewing. You can pick up a decent pair for around $50-100. Photo: Bob King

As far as the best instrument to use, we’re all hoping PANSTARRS will be bright enough to see plainly with the naked eye. Based on its predicted brightness and tail development, a binoculars will probably provide the best view.

Get a pair that magnify between 7x and 10x with an aperture (lens diameter) of 40 to 60mm. 10×40, 10×50 and 7×50 models are perfect, and they’re reasonably priced, too. Avoid binoculars that magnify 20x or 30x. While more power sounds tempting, anything above 10x will narrow the field of view and make the binoculars nearly impossible to hold steady.

My favorites are the 10×50 wide field variety with lots of eye relief. Large eye relief lets us unfortunates who must wear glasses see the entire field of view instead of getting the equivalent of looking through a straw.

Uwe Pilz of Germany wrote a program that follows the path of dust particles in comets and created these excellent simulations of PANSTARRS’ dust tail. The aqua blue line points away from the sun; the black line is 0.9 degrees long so you estimate tail length. Click image to see the larger complete set. Credit: Uwe Pilz

Comet PANSTARRS is what astronomers term a dynamically new object, making its first visit to the inner solar system after millions of years in the deep cold of the comet repository known as the Oort Cloud. Such comets make a bright appearance at great distance because their rarefied ices are ripe to vaporize. This can lead one to think that the comet will continue to brighten into negative magnitudes as it approaches the sun and Earth. But after those virgin ices have sublimed away, new comets often settle down and lag behind predictions. The old hats who’ve been around the block a few times brighten and fade more reliably.

Whatever happens with PANSTARRS is worth watching. As we’ve encountered with previous comets, unpredictability is their charm. The comet could be brighter, fainter, experience a sudden outburst of brightness or disintegrate into clods of dust. I hope we’re all fortunate enough to witness such revelatory moments in nature.

27 Responses

  1. Edward M. BOll

    Even if Panstaars brightens to magnitude -1 at perihelion, which is still possible, by March 31 it will have likely faded to around 4th magnitude, probably fainter than Lemmon by then.

  2. Edward M. BOll

    I believe at best Panstaars will be kind of like a slightly dimmer version of Hyakutake from March and April of 1996, which was clearly visible to the naked eye from SD and MN for about a month.

  3. Giorgio Rizzarelli

    Just the article I was looking for, as you say this comet requests a careful choice of observing site.
    We have sea at West here in Trieste. I don’t know if it will be better sea – with 0 high horizon but also city light pollution and often mist/clouds – or the highland country at East in Slovenia, having 5-10 degrees W horizon, but darker.

    1. astrobob

      That is a hard choice … hmmm. Maybe the comet will be bright enough for a nice view in Trieste. You can always check, and if it isn’t, head for the mountains instead. I’ve been faced with decisions like that recently. I wanted to see T5 Bressi a couple weeks back when it was very low in Cetus/Sculptor, so I took a chance and drove s.west of Duluth to where I thought there was no light pollution. Sadly, there was anyway from a nearby ski hill I’d forgotten about. I set up my scope on a pullout near the road and had to deal with car headlights and someone who parked their car nearby playing the most evil music. Glad to get out of there finally! Not sure if I ever did see Bressi – the observation was tentative.

  4. Buffy

    hey bob I just have a question…. do you know anything about the super close asteroid that is suppose to pass earth on the 15th of this month? are you gonna post something about it? I just read about it on msn and would like ur view on it… I mean its the closest approach ever they say… are they sure it wont hit? thanks Bob so much…… 🙂

  5. Wayne Hawk

    Aloha Astro Bob and Everyone!

    I don’t want to distract from your Comet PANSTARRS blog because it is important information and I really had to wrestle with myself in posting anything about 2012 DA14. Two things helped me decide to post something; 1) buffys’ question/reply above and 2)’s 1/28/13 article. Perhaps I should have said “three things” because I simply don’t have the patience to wait for your blog. If this upsets you, please feel free to reprimand me and/or delete this inquiry as I never intend to upset you or anyone with my “replies”, OK?

    I’m sure I’m not alone in keeping a close eye on the “progress/approach” of 2012 DA14, I simply want to alleviate any anxiety that may be building in certain folks and I hope this small “notice” from NASA Science News has this result:

    “On Feb. 15th an asteroid about half the size of a football field will fly past Earth only 17,200 miles above our planet’s surface (Mt. Everest is approx. 5.5 miles high). There’s no danger of a collision. The impact of a 50-meter asteroid is not cataclysmic–unless you happen to be underneath it. 2012 DA14 is a fairly typical near-Earth asteroid. It measures some 50 meters wide, neither very large nor very small, and is probably made of stone, as opposed to metal or ice. A similar-sized object formed the mile wide Meteor Crater in Arizona when it struck about 50,000 years ago. That asteroid was made of iron which made it an especially potent impactor. 2012 DA14 will definitely not hit Earth. The orbit of the asteroid is known well enough to rule out an impact.”

    For the complete article, go to or click on:

    Simply put, just like the infamous “12/21/12” date was false, any reports of an apocalyptic collision on 02/15/13 with 2012 DA14 are also false. Astro Bob, how much ‘faith’ do you have on this particular prediction by NASA? If you wish, you may wait until your blog on this NEO to answer since I’m being premature in discussing this.

    Aloha Just For Now!

    1. astrobob

      I hereby reprimand you and sentence you to 20 lashes. No, don’t worry about it. This asteroid’s just a fly that will buzz through the room and depart. I haven’t written my take on the whole thing yet because of the time involved in drawing up useful charts. It’s also still nearly two weeks away. Surprises me that so many big dogs have already jumped on it. I will say this: no one without a telescope will see 2012 DA14 in the U.S. and Canada. It will be visible in binoculars from Europe if you know exactly where to look. On the other hand, Comet L4 Panstarrs will be widely visible across the planet.

      1. Wayne Hawk

        Aloha Astro Bob!

        Whew! Thanks for the light “sentence”! LOL! I’m extremely relieved I didn’t overstep my boundaries, so to speak. Even though you seem to have an “even” demeanor, one never knows until one has “tested” it. I appreciate your response greatly.

        Aloha For Now!

  6. H.Bob

    Great comet watching tips AstroBob. Thank for the heads up and just the info I needed! Hoping the skies will be clear of cloud in March so that I can catch a sight of it.

  7. curious

    Dear Curious Bob: I don’t understand the comet Panstarr’s orbit. Will it be visible during the day or just at night?

    1. astrobob

      The comet will only be visible in evening twilight (at first) and then during the night as it moves farther from the sun into a dark sky. It won’t be visible in the daytime.

  8. Peter

    Hi Bob!! I will be around altiplanic place in Bolivia just on time to the comet.
    Will the comet be high enough to see it from La paz , Bolivia?? Night sky there is really dark. Congratulations for your web page and share with all people your astrofever!!! bye bye Peter

    1. astrobob

      The comet will be visible from La Paz but very low in the western sky. Early half of March is better as PANSTARRS moves north and soon becomes better-placed for the northern hemisphere.

  9. Syed S

    Bob, can you recommend a good 10×50 binocular for someone who needs ample eye relief and wants to wear glasses while observing? I usually use long eye relief eyepieces with my scope and was wondering if there was a binocular equivalent. And oh yeah, as always, very informative posts with the critical information we desire!

    1. astrobob

      Hi Syed,
      The Nikon Action 10x50s are very good for the price but eye relief, while not bad, isn’t enough to see the full field with glasses. Nikons at:×50

      You might also consider the Orion 10×50 Ultraviews with 22mm of eye relief, which should be plenty:×50-Wide-Angle-Binoculars/c/5/sc/72/p/9351.uts

    1. astrobob

      I’m not aware of a specific site for Bangalore, however at your latitude of 13 degrees north, you can take the chart I made for the central U.S. and “tilt” the arc of the comet’s path higher up on the left and lower down on the right. In other words,
      the comet will be a little higher for you in the first half of the month. I’ll have a more detailed chart up on the blog on or about March 6.

        1. aravind benaka

          bod , sorry I cld not get the information… Plese can u post the link for me.. I am confused with loads of information..

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