Looking Forward To Comet Elenin

Comet Elenin photographed on June 23, 2011. The comet shows a small, brighter head or coma and a short, faint tail. Deep within the coma is the actual comet nucleus, estimated to be several miles across. Credit: Erik Bryssinck

Normally I wouldn’t spend so much time on a comet that most people won’t be able to see until October, but Comet Elenin is special. There’s so much misinformation online about this rather ordinary object that I thought it time again to share what I know from my observations and those of others.

New brightness estimates based on the comet’s current light curve and tables prepared using the NASA’s extremely useful Horizons site indicate that Elenin will only reach 6th magnitude when brightest in the fall. Since magnitude 6 is the naked eye limit for stars seen from a dark site, that means we’ll need binoculars to see it.

But I’m getting ahead of myself. Currently the comet is in the constellation Leo the Lion, where it will remain until August 7, when it moves into Virgo. Leo is sinking in the western sky for observers in the northern hemisphere. Matter of fact, Comet Elenin is now so near the western horizon by nightfall, that few if any observers living in mid-northern latitudes will see it again until it returns to the morning sky in October. The comet remains stubbornly dim with a current magnitude of around 12. Combine that with the usual low altitude haze and you’ll need a very large amateur telescope to pluck it.

Comet Elenin is now so low that it's virtually invisible to northern U.S. observers. The situation improves the farther south you live. Illustration created with Stellarium

The situation improves the farther south you live. Here in Duluth, Elenin is only about 10 degrees high by the time it’s dark enough to look for it, while in Tucson, Ariz. it’s closer to 20 degrees. As you can see from the illustration above, the best views are from the southern hemisphere.

Elenin hugs the horizon and remains in twilight from the northern U.S. and Canada now until it pops into the morning sky in October. Happy trails till we meet again! Those living in the southern hemisphere however will continue to be able to watch the comet all the way into early September, when it might reach 7th magnitude.

From mid-September through the start of October no one will see Elenin, because it will be too near the sun and invisible in its glare. Around October 4, it will enter the morning sky in fine form in Leo for observers in the northern hemisphere. Since the comet is closest to Earth around this time, it will cover ‘ground’ quickly, becoming easier to see each morning as it moves higher in the sky. Because of the comet’s angle to the horizon, southern hemisphere observers will need to wait a few more days for its re-appearance.

The path of Comet Elenin from late June through mid-October at 15-day intervals. After passing near Saturn, it swings back west in retrograde motion, appearing in the morning sky in October. That's when we'll see it best. Created with Chris Marriott's SkyMap software

Comet Elenin is one of many comets visible in the sky in 2011. At the moment there are are about a half dozen, most of which of which are on the faint side like Elenin, requiring at least an 8-inch telescope and dark skies to see.

People always want to know how big the comet is. Most comets are smaller than 6 miles across and Elenin appears to be no exception.  Since that’s less than a billionth of the mass of the Earth, its gravitational effect on us is positively miniscule. Add in the fact that at closest on October 16, the comet will be 22 million miles from Earth, and there’s nothing to fear. Consider that Venus is nearly the same distance – 26 million miles – at inferior conjunction every couple years with no ill effects. Heck, that’s an entire planet!

According to Don Yeomans of NASA’s Near-Earth Object Program Office at NASA’s Jet Propulsion Laboratory: “Comet Elenin will not only be far away, it is also on the small side for comets. And comets are not the most densely-packed objects out there. They usually have the density of something akin to loosely packed icy dirt.”

Comet Elenin will be about 2.25 degrees north of the sun at conjunction on September 26. Created with SkyMap

The following is a list of things to look forward to as Comet Elenin gradually brightens up in the next few months. Consider it an Elenin ‘planner’, but remember – while distances and visibility prospects aren’t likely to change, it’s possible the comet might be brighter or fainter than expectations. Of course, we always hope for brighter! And although Elenin has only a short, faint tail at the moment, it will undoubtedly develop a brighter, longer one as it gets closer to the sun. And if it does anything crazy, I’ll update you right here.

* June 28 – Currently at 13 magnitude and 165.5 million miles from Earth. Located low in the western sky and nearly impossible to see from more northern latitudes.
* August 7 – Moves from Leo in the constellation Virgo. Earth distance: 133 million miles. Now at 10th magnitude. Might still be visible from the southern U.S. very low in the west during late twilight through a telescope.
* First week of September – Now at 7th magnitude and visible in binoculars very low in the west to experienced observers in the southern hemisphere. Earth distance on the 3rd: 84.3 million miles
* September 11 – Perihelion or closest approach to the sun. Sun-comet distance: 44.6 million miles. Earth distance: 65.1 million miles. Comet lost in the sun/twilight glare and not visible. Magnitude 6.2
* September 26 – Elenin about 2.25 degrees due north of and in conjunction with the sun (closest to the sun seen from Earth) . Contrary to what some websites are saying, it won’t ‘eclipse’ the sun. It won’t even pass in front of the sun from our perspective. The comet will shine at magnitude 6.0 but won’t be seen because of solar glare. Earth distance: 36.7 million miles
* Around October 4 – It’s finally here! Appears low in the morning sky at dawn in the constellation Leo while fading to magnitude 6.3. Earth distance: 27.9 million miles
* October 16 – Closest approach to Earth at 21.7 million miles. Magnitude 7.0

63 Responses

  1. R G

    why do you think that the JPL shows other comets in an rounded, smooth eliptical manner yet the Elenin view is shown with sharp lines/turns?

    1. astrobob

      Hi RG – not sure which orbital diagram you’re referring to. Do you have a link? The ‘smoothness’ of the orbit’s appearance may also depend on the software used. Elenin’s orbit is a very open, hyperbolic one rather than a nice, tame ellipse. After it passes through the inner solar system, Jupiter may perturb it into an elliptical orbit.

    2. CJV

      The reason you’re seeing the sharp lines in the orbit is a matter of zoom on the JPL. Why would nasa make hundreds of small lines to show the tight elliptical orbit of this comet when you zoom close in? If you pull the camera back (or zoom out) you see the “smooth elliptical manner” that you get with the other comets viewed in the JPL. Your paranoia has you making something out of nothing.

    3. Davide

      Wath do you think about this:
      09 hours 47 minuts 57.30 sec + 13 degrees 16 feet 44 inc,at this time?

      1. astrobob

        Davide, I think the position you list is very close to the sun’s current position. By the way, the second number should be +13 degrees 16 minutes and 44 seconds, rather than feet and inch units.

  2. Kevin Heider

    I assume the reader is referring to the generic 2-body (Sun+Comet) JAVA applet at JPL:

    The readers should note that this generic JAVA applet does not take planetary perturbations into account. It even includes a disclaimer that says:
    “The applet was implemented using 2-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances. For accurate long-term ephemerides, please instead use our Horizons system.”

    The comet is just now starting to get a total magnitude (coma+nucleus) brighter than magnitude 13. The nucleus is still around magnitude 15.

    Bob, thank you for your Elenin update.
    — Kevin Heider

    Comet Elenin – Official Facebook Page

  3. Just-a-thought

    I really hope AstroBob is right.

    But when he says: “There’s so much misinformation online about this rather ordinary object…” does it not appear that he may NOT have in any serious way considered the evidence that others have presented? And are Bob’s actions wise when one considers the potential dangers to humanity IF others are even remotely correct?

    1. astrobob

      First, there has to be evidence to consider. Alignments do not constitute ’cause and effect’ evidence for the multiple reasons I and others have detailed in the blog and Comments area. As soon as I hear voices from the worldwide professional astronomical community call Comet Elenin anything other than a typical comet, I will change my tune. Until then, I’m sticking with what we know. If I were to entertain all the crazy, nonsensical ideas about Elenin’s comet – Nibiru, brown dwarf, earthquake spawner, neutron star, extinction-level-event, etc. – I would be short-changing my readers on facts, filling them up instead with completely unwarranted fears. A Google search will (sadly) turn up reams of pseudoscientific hogwash about the comet. As for this blog, it’s main purpose is to share the many wonders of the night sky and provide updates on what we can expect to see of comets, eclipses, etc. Relax, look up and enjoy.

  4. William Shimandle

    If there is such a thing, “and i am not saying there isn’t”. Why is there not anything on the news about this threat. If there is a threat it should be known by now so people can make proper arrangements. and we should have constant updates about it. I amn no scientist, but have been interested in outer space for some time and would love to see the universe through a big scope. i got a scope here, but is a small one and have not seen much more than the moon surfice. If i had the money I would seek to buy a new scope to see the wonders that are out there. Only wish there were some way for me to see this in observitory conditions. I wish i had the knoledge to become a astrologist. but that takes money and time.

  5. Eric

    I know you already explained that Elenin will not hit us.. but what about Honda or Levy? you don’t hear to much about those.. will they impact earth? it’s pretty nerve wracking.

    1. astrobob

      Dear Eric, neither Honda nor Levy is on a collision course with Earth. These are periodic comets that have been in the neighborhood before. 45P/Honda-Mrkos-Pajdusakova was discovered in 1948. It will pass 5.6 million miles from Earth on August 15. That’s a healthy miss. Comet Levy is another returning comet discovered by David Levy in 2005-06 (can’t remember which date at the moment). It will pass 17.8 million miles from Earth in late January – an even healthier miss.

      1. Eric

        thank you.. it’s really good to hear the facts instead of all the doomsday nonsense.. not only is it a sigh or relief for myself.. but also for my kids.. so i thought i would ask an expert. once again thanks for the info

        1. astrobob

          Eric, you’re welcome. I’m a believer that a few solid facts are preferable to endless speculation.

  6. aiyana gregori

    Why do you say that this commet wont do anything, in consequence, that its alignment has been relation to the last three major Earthquakes>>>??? It seems strange that you think nothing will happen, the poles wont flip… etc Im interested in a good explanation about why not.

    1. astrobob

      Dear Aiyana,
      Because it’s all speculation with no science or research done to back up these claims. I and others have addressed the alignment question many times in the blog and in particular, in the Comments area. Please page back in Comments or Google ‘Astro Bob’ and ‘Elenin’ to find the blogs.

  7. Gus be

    I am looking foward to this, but i aint understanding the magnitudes they are giving. So I want to know if it can be seen in chicago,il? And if yes, around what time and what day?

    1. astrobob

      Hi Gus, unless Comet Elenin becomes unusually bright, you probably won’t see it from Chicago — at least not the city. You’ve got too much light pollution. From surburban Chicago, especially away from the city, it should first become visible in binoculars in early October in the pre-dawn sky in the constellation Leo. Observers living in dark, rural areas will probably see it faintly with the naked eye.Only observers living in the far southern U.S. and points further south using a moderate-size telescope can see Elenin right now. For the rest of us the comet is too near western horizon and lost in the glow of evening twilight.

  8. Gus be

    So any suburb in Chicago will make elenin possible to see? And thank you for the help. But around what day will it be visible?

    1. astrobob

      Gus, the comet will start to show low in the east at dawn around October 4. It will be up higher in a dark sky before the start of dawn by the 7th. Elenin will continue to get higher and easier to see through the month but will slowly get fainter as the month goes on. Hard to say which suburbs are the best. Since the comet’s in the east, plan to go somewhere with a minimum of city lights and a good, unobstructed view in that direction. I will provide a finder chart as we get closer to the date.

    1. astrobob

      Good question. I can’t say exactly. Since many work for universities, colleges or government (NASA), they would get paid a salary depending on the university/institution and what degree they have – PhD, Masters and so on.

  9. Jon

    Hi Bob,
    Looking at the predicted path shows that elenin will just about cross mercury’s orbit. When is elenin coming back and has it been calculated where the earth will be on the next encounter-is it even possible to do this accurately with the data known.If not why not because we know the precise locations of all the planets so surely pertubations can deduced or is it a too many variables/accuracy thing?

    P.S. I find it amazing that stars that are light years away can knock comets out of the oort cloud into unstable orbits,whats next I wonder

    1. astrobob

      Jon, I’m not sure if anyone knows the exact orbital period of Comet Elenin yet, but it’s extremely long — I’ve seen estimates of approximately 1 million years. Over such a long haul, it’s hard to say exactly where it and Earth will be in relation to each other during its next visit because of potential perturbations from the outer planets during its lengthy coming and going.

      1. Sometime ago I used a program called Red shift 4. You could fast forward in time and space(like a time traveller lol) for the stars and predict eclipses. Its probably come on a lot since I used it in about 05.Fast forwarding is 1 thing being accurate is another though.

  10. waimabigeyes

    hi bob .4 alighnments 4 events.wouldnt it be wise to expect a 5th event on the 5th alighnment when elenin is alot closer?im preparing for another earthquake around late september,thanks bob

    1. astrobob

      There is no scientific proof that alignments are in any way remotely connected with earthquakes. No research using the scientific method. Especially alignments with such minor bodies as comets. I think people believe alignments are important because of coincidence and because it ‘feels right’. They also seem unusual, but nothing could be further from the truth. Alignments happen all year long between Earth and numerous celestial bodies ranging across the spectrum from the moon, the planets, hundreds of comets and thousands of asteroids. Pick whatever comet or asteroid you like, work backwards or forwards in time, and you’ll find a bonanza of alignments you can use to ‘explain’ every bad day on Earth.

      Where are the comets and asteroids for the many major quakes that have happened in the past 100 years? And why is plate tectonics, a well-proven and accepted theory for earthquake and volcano eruptions, blissfully ignored by so many comet doomsayers?

  11. Rick

    i was looking at the elenin tracking
    and just wanted to see when it started where the line starts
    i played it backwards to the begining of the line thinking it would be around the date it was discovered
    but in fact it started in 1947
    that seemed to be the same time of roswell crash . if it started in 2010 how would they know exactly where it was in 1947 . hmmm!!
    whood a thunked it

    1. astrobob

      Once an orbit is determined for a comet, astronomers can predict not only where it’s going but also where it’s been. Back in 1947, Comet Elenin was in the constellation Cancer and 8.4 billion miles from Earth — nearly three times farther than the dwarf planet Pluto. The comet remained in Cancer until 1984, when it crossed the boundary into the constellation Leo. Prior to 1947, it had been in Cancer for many thousands of years.

      1. Rick

        thanks .
        i was just curious
        just thought it was kinda odd that it started in 1947 coinsidence i suppose .

  12. Jessy

    Would elenin have any effect on earth? And it will be better to see elenin on october 16? Since it’s closer to the earth?

    1. astrobob

      Hi Jessy,
      Comet Elenin is not expected to affect Earth in any measurable way except if it gets brighter than expected. If that happens, more people will be able to enjoy it 😉
      Anytime it’s clear before dawn after about the first week of October will be a good time to see the comet. October 16 sounds great.

  13. Jessy

    I recently just saw a video that there is a second moon that passes every 700 and something years. Is that ture? And the video showed a diagram of the moons path and it will be close to earth on Oct. 4,2011.? So can we see elenin and the moon? Cruithne is the name of the moon.

    1. astrobob

      Hi Jessy, it would be more accurate to call 3753 Cruithne an asteroid rather than a second moon, because it’s not gravitationally bound to Earth like the moon. It’s 3 miles across and orbits near the Earth, so it will be millions of miles from Elenin just like Earth. I don’t know if Cruithne will be in the same part of the sky as Comet Elenin on that date or not. Either way, it’s too faint to see with the naked eye or binoculars. You’d need a large amateur telescope (around 14-inches) to spot it. As for the 700 year period, I can’t find any reference to it. The asteroid’s next series of close approaches to Earth will be around 2292 with a distance of 7.8 million miles.

  14. Adam

    Passing over ORION belt (posted by NASA)


    How is it that NASA claim is that the movie is taking from camera –Stereo (behind) spacecraft? This must be a clear mistake. At this moment only spacecraft Stereo (ahead) has the view on ORION belt. Please do yours own research and let me know if I am wrong.
    I agreed that stereo (behind) is only 7 million kilometers from Elenin. The problem is that this short movie is taken by camera (ahead) that is on other side of the Sun. Check the movement of the comet itself is moving left to right .Please correct me if I am wrong

    Location of Stereo Ahead and behind in relation to Comet Elenin:

    Solar system in real time:

    Back to Stereo home page:

    1. James

      There Is no science behind your claim Adam.

      The SECCHI flight Has Been updated database and fits the raw files for STEREO-B’s observations are now available of Elenin for 8/1/11.


      If you’re Unfamiliar With This form, you want the date to September to cover 8 / 1, you want HI-2 camera, Observatory B, all other settings left at default Can Be.

      Here is a stack I did of These files using DeepSkyStacker, With stack in September to the track on the comet, Rather Than the stars (Which you produce trailed stars, Mostly due to a double image the way the timing occurred With The images):


      These images were not Photoshop and There is no reason to believe They Were.

      That was your claim, right?

  15. ingrid dup

    Dear Astrobob,
    As time passes, more and more scientists are getting involved in studying Elenin. IF it is really the “wimpy” comet described by Don Yeoman, why the interest and waste of resources? Leonid Elenin just published a new article on his website wherein it is mentioned that more and more scientists are getting involved in the study of Elenin and that two more spacecrafts are going to participate in the observations…. it makes me think very hard and deep about this little insignificant comet….http://spaceobs.org/en/tag/co

    1. astrobob

      Hi Ingrid, it’s nice to see some interest building. Several of these opportunities were known in advance and are passive observations, ie. the coronagraphs, while others were clearly planned or in the planning stages. Elenin provides some good opportunities for study while near both sun and Earth. I find it interesting that when NASA didn’t appear to be showing much interest, people suspected the agency of hiding information, and now that several spacecraft will watch it, people are equally suspicious.

  16. Jessy

    Im sorry for all the comment but i heard there will be a meteor shower today. I just want to know when it could be seen in Chicago.(what time). Can you inform me as soon as possible?thabk you. Im so excited

    1. astrobob

      Jessy, if you’re right in the city, it will be very difficult to see any meteors because of light pollution, but if you’re in the suburbs, you have a better chance. Go out and look toward the east or south after 10 o’clock. The later you stay up, the better chance of seeing more meteors. Try to observe from somewhere where there’s as little light as possible shining around the neighborhood to allow your eyes a chance to get used to the darkness. Be patient and good luck!

  17. Jessy

    Thanks. In yahoo it said that it will be visible even in the cities because the meteor will be bright. It even mentioned the places/cities such as new york, chicago, and L.A. Will sunglasses help. Im joking.

    1. astrobob

      Jessy, please get back to us with a report from Chicago. I would enjoy knowing how many you got to see.

    1. astrobob

      Jessie, I’ve seen some very nice fireballs including one very long lasting “Earth grazing” meteor, but never a REALLY big one, say as bright as the full moon. And you?

  18. Dennis

    astrobob can you explain to me why on google earth while in the sky mode viewing space there is one spot block out by google earth program ( 5h53m27s,-6 10’58 ) ( that is the location that is blocked out ) what is behind that spot that blocked out ? I do believe this comet elenin may not be a threat to earth as you
    claim in this blog but I do know this if it was a threat to earth I know we wouldn’t
    told the truth because it would cause mass panic so for know I will take your word as the truth

    1. astrobob

      Hi Dennis, with so many people watching the sky — thousands of professional astronomers across the world and even more amateur astronomers — I doubt anything major like you suggest could be kept a secret. I’ve addressed the ‘missing data’ in a previous Comment reply, but that was several weeks ago. It relates to an older sky survey that was used to create Google sky. There is a complete and excellent presentation here: http://www.youtube.com/watch?v=_VZY115vfYk
      Check it out and I guarantee your question will be answered.

  19. roger

    hey bob, just wondering about a few things. This if I remember right started out with the notice of a tug on jupiter, you say the gravitational pull of the comet is pretty much nothing, but if it can make a tug on jupiter, before it was even in the solar system, wouldn’t it make you think it would do more being closer. I don’t know much about how these things work, so if could sum it up that would be great. The other thing is since this is a hyper comet, the questions above about why the greater interest, well I don’t think we have ever had a hyper comet come through out solar system, correct me if I’m wrong. I think that alone would be of interest. Another question is alot are calling this more than just a comet, there was information on the web, be it real or chaos dooms day stuff, but it said the Russians released a statment saying that elenin actually slowed down and changed course, any information on this on your end. Finally I wanted to comment on the allignments and earthquakes. We all know that this earthquakes are at an all time high, and are increasing in numbers, that’s fact, and you said pick any allignment and you can say whatever you wanted basically about any event. I love numbers and probability, if you factor in everything that people are asking on this forum including the probability of the quakes, the number of probability is extremely extremely large, at what point do you stop saying it’s just by chance all this is occuring since the approach and allignments of elenin, and since so much interest in this thing why isn’t there any scientific study on it being done, you think that would for sure make them want to look into it. Thanks

    1. astrobob


      — Comet Elenin did not tug on Jupiter unless you mean that every object gravitationally tugs on every other object. Comet Elenin’s pull on Jupiter, Earth, the moon, etc. is utterly insignificant.
      It’s the other way around — Jupiter’s pull on the comet is very significant IF the comet comes near the planet, which it didn’t.
      — There’s no such thing as a ‘hyper’ comet. You’re probably confusing that with comets that move in hyperbolic orbits. Elenin has been determined to be in a very large elliptical orbit (similar to many comets) with a period of about 1 million years.
      — Comet Elenin is a comet because it looks, behaves and orbits as a comet. If it quacks like a duck …
      — I don’t know about the statement from “the Russians” whoever they are, but the comet is exactly on orbit and where it’s supposed to be. Perhaps someone is confusing this with the fact that all planetary, asteroidal and cometary bodies in the solar system begin to slow down after perihelion. Perfectly normal behavior.
      — Where is the scientific data that says that says “earthquakes are at an all time high”? Look back over just the last 100 years and you’ll find hundreds of them. Earthquakes will continue unabated far into the future, some minor and some horrific. Alignments do not cause earthquakes. I brought up the thousands of “alignments” that occur everyday as proof they DON’T have any connection with earthquakes, for if they did (and they don’t) the Earth would be shaking nonstop! There is no scientific evidence indicating a connection between comets, asteroids and planets and earthquakes. Earthquakes are caused by forces internal to the Earth. Look it up and you’ll better understand tectonic forces operating on our planet.

      1. astrobob

        Comet Elenin is not doing great. It’s falling apart and fading. Should there be anything left of it, it will be closest to Earth on Oct. 16 at a distance of 22 million miles. It will not affect our planet in any way, so New York’s good.

        1. Chantal

          Hi Bob
          have you seen the comment of southern comets – states directly that Elenin did not survive perihelion – do you have an opinion, is this pre-emptive? – thanks

          1. astrobob

            No, I haven’t checked there for a couple days. The comet is still around so yes, it has definitely ‘survived’ for the time being. I know the page author and I think he’s anticipating its ultimate demise.

  20. Chantal

    have to say this does contradict southern comets – he is very certain states in bold has not survived perihilion. Thanks

    1. astrobob

      As an intact comet, it has not survived perihelion, however there is still a comet there composed of disintegrating fragments. It’s how “survival” is interpreted.

  21. Chantal

    you are the expert, and I am not meaning to be disrespectful and contradicting – but there is also an image stating comet is not visable – does this mean that it has just dropped to a magnitude that is too low for imagery to pick, or disintegrated completely. maybe I dont understand the terminology correctly
    thanks again Bob

    1. astrobob

      Much depends on the exposure and instrument as to whether the comet will show. Certainly the latest pictures still show surviving cometary remains despite their faintness.

  22. sally

    Bob, I have seen many rumors on the internet that elenins tail will enter earth on nov 11th and cause major issues… Is this true ? I would like to think its not but with all the drills going on the past 2 days , it really makes me wonder and I’ve never been more afraid in my life. I cant sleep because im so afraid that ” today will be the day” 🙁

    1. astrobob

      Hi Sally,
      Comet Elenin – what’s left of it – is over 38 million miles from Earth and has never posed a threat to our planet. Consider that both Mars and Venus get closer than that all the time and nothing bad happens. Ignore the fear mongers and all the 11/11/11 stuff. It’s just nonsense meant to scare and all untrue. Go out tonight and enjoy what’s up in the sky – it’s a full moon!

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