Speedy Comet Honda To Pass Near Earth Next Week

Comet Honda-Mrkos-Pajdusakova photographed by Australian amateur astronomer Terry Lovejoy on August 5.

It wasn’t but a week ago I was observing Comet Honda-Mrkos-Pajdusakova, which for simplicity we’ll call Comet Honda-M-P. It was very low in the southern sky in the early morning hours and a tough catch in the constellation Pisces Austrinus the Southern Fish. Using the “lure” of time, I made two observations – one around midnight and the other at 2 a.m. This way I was able to track and positively identify a faint, round hazy glow that slowly inched across the starfield over the span of two hours. Terry’s photo above captures its appearance well.

Sure wasn’t much to look at, but finding an old friend is always a pleasure. I last saw the comet back in 2001 and before that in 1995. Honda-M-P is what astronomers call a returning or periodic comet, similar to Halley’s Comet but with a much smaller orbit and hence a shorter times between returns. It was discovered by Japanese amateur astronomer Minoru Honda in 1948 and seen at nearly the same time by astronomers Antonin Mrkos  and Ludmila Pajdusakova.

Honda belongs to the short-period Jupiter family of comets or those with orbits less than 20 years under the control of the gravitational powerhouse Jupiter.  As it orbits the sun with a period of 5.3 years, it occasionally makes close passes to the planets Venus, Earth and Jupiter. When near Jupiter, the planet’s powerful gravity can alter the comet’s orbit and change its period slightly. This last occurred in 1983 and will again in 2030.

Comet Honda-M-P covers a lot of ground in the next week, plunging through the southern constellations Grus, Tucana, Hydrus and Dorado as seen from Australia. Credit: Chris Marriott's SkyMap

Next Monday August 15, Honda will pass very close to the Earth – relatively speaking – at a distance of just 5.6 million miles. To put this in perspective, that’s 23 times farther than the moon or still a long ways off. I’ve been asked if the comet will affect the Earth in any way, and the answer is ‘no’. Honda is only 0.6 miles across and far too tiny to produce any measurable effects on our much more massive planet. If anything, it’s the other way around. Earth may very slightly alter the comet’s orbit.

When I saw the Comet Honda-M-P, it was very faint in a large amateur telescope (15-inch). Today it’s brighter at magnitude 8.5 with a coma or cometary atmosphere measuring about half the size of the full moon.

If you’re worried that Earth might pass through the coma, don’t be. At Honda’s present distance of 9.3 million miles, the hazy glow around the tiny cometary nucleus is about 43,000 miles across, much too small to reach out and brush our planet. Even if we did pass through a comet’s outer coma, its effects would likely amount to a nice show of meteors at best. Comas are highly rarefied – any ice, dust or small rocks would quickly vaporize on striking the upper atmosphere.

Comet Honda-M-P animation compiled using photos taken on July 21. Click for more comet photos. Credit: Michael Mattiazzo

The closer a celestial object is to Earth, the faster it appears to move across the sky. Because the comet is closing in on minimum distance from Earth, it’s quickly picking up speed, covering more and more ground as we approach the 15th. Tonight for instance, it travels some two degrees or four times the full moon’s diameter in the southern constellation of Grus the Crane. Tomorrow that increases to three degrees, and by the 14-15th, Honda-M-P flys across some 10 degrees of sky- your clenched fist held at arm’s length – in just one night!

The next night or two, the comet will still be visible from the far southern states low in the south around 1 a.m., but by the 14th, only southern hemisphere observers will see it. To spot the comet, you’ll need at least a small telescope, since it’s very diffuse and will get no brighter than 8th magnitude. The moon will also be near or at full phase, lighting up the sky and making it even harder to find.

Two side-by-side binocular comets at dawn in Leo on October 7. Created with Chris Marriott's SkyMap

After closest approach, Honda-M-P swings back north and slowly continues to brighten, reaching 6th magnitude (naked eye limit) in late September, and finally appearing in the morning sky before dawn for northern hemisphere sky watchers in early October. It’s expected to be an easy binocular comet then, shining around 7th magnitude.

On the morning of the Oct. 7, it will be joined by Comet Elenin four degrees (eight full moons) to its north. Although both comets will be at different distances from Earth – 90 million miles for Honda-M-P and 22 million for Elenin –  they’ll lie in approximately the same line of sight. With wide-field binoculars you’ll be able to catch them both in the same field of view. What a wonderful and rare sight this will be!

Speaking of Comet Elenin, southern observers continue to observe and photograph it. It’s now magnitude 9 with a 3-4 arc minute coma and visible in 4-inch and larger telescopes. Click HERE for the latest views of the comet with the STEREO-B (behind) solar telescope.

34 Responses

    1. astrobob

      Hi James, not to worry. The comet’s chugging along in its orbit as predicted and won’t suddenly jump off the track. Just a few short weeks ago, the asteroid 2010 MD passed just 7,500 miles from Earth and as predicted and all went well.

      1. James

        thank you for answering my question i have one more could a powerful CME solar flare change a comet orbit?. i know a tail can be knocked off from one i think.sorry for all the questions i am new to astronomy i just started to learn it more i always love space and whats in space

        1. astrobob

          Definitely a switch in solar wind direction or speed can snap off a comet’s tail. It then regrows a new one just like some lizards do. I’ve not heard of a CME changing a comet’s orbit. We’re talking very tiny, subatomic particles in a rarefied cloud, so it’s doubtful, but I can’t say if it never could happen.

  1. Brandon r

    Hi astrobob,I’m going to myrtle beach in sc next week and I was wondering if I would be able to see the comet?

    1. astrobob

      Brandon, sorry to say, you’ll likely not see the comet. About the time the sky is dark enough in the west after sunset from Myrtle Beach, the comet will only be about 5 degrees high. You’ll need an open horizon in that direction, a super-clear, haze-free sky, a good star map and at least a 8-inch telescope to attempt it. Maybe a larger scope, because at that altitude, the comet will be dimmed considerably by the thickness of the atmosphere.

  2. Eric

    hey astrobob do you know how many LD this will be from us? and do you know anything about that unknown comet that may have led to the random meteor shower during february?

    1. astrobob

      Eric, I believe I stated how many LD (lunar distances) Comet Honda-M-P will be from Earth next week. As for that brief shower, I don’t know any more than astronomers suspect a long-period comet. It’s not related to Elenin. Most meteor showers have a “parent” comet from which they originate.

        1. astrobob

          Eric, You’ll see that everything will be fine. Enjoy the upcoming meteor shower. I saw some great Perseids with my daughter last night.

          1. astrobob

            Eric, go out late if you can. We didn’t see much until around 1 a.m. this morning. The moon’s definitely a spoiler though. The shower will improve toward its maximum Saturday morning before dawn. You’ll have lots of moonlight then, but the stronger shower activity will compensate for the moonlight. Check the weather and pick the best day.

  3. Diane

    We plan to view the Perseid meteor shower from the Great Sand Dunes (in southern Colorado) Friday (Aug 12) night to Saturday morning. Which direction should we be looking?

    1. astrobob

      Hey Diane, sounds like a great spot! East or southeast are good directions, though you will see them all over the sky.

  4. Eve

    hey bob, I’m in Oregon what’s the chances I’ll be able to get a view of this? Also i know Elenin is a relatively new discovery. Do we know yet how many years it will be before it comes back this way? Has there been any speculation or will it even come back this way at all?

    Also thank you for being a voice of reason on the internet. There are so many sights promoting disinformation it’s refreshing to find someone who’s being objective.

    1. astrobob

      Hi Eve – yes, you’ll get a chance to see Comet Elenin in October when it appears in the morning sky. It should be bright enough then to easily see with binoculars. Comet Honda-M-P will also be visible around the same time in the morning sky not far from Elenin. Unfortunately it will be fainter. You might see it in binoculars, but a telescope will be better. Comet Elenin will return to the inner solar system in about 12,000 years.

    1. astrobob

      Hi John,
      Comet Honda is still only visible in the southern hemisphere. Most U.S. locations won’t see it until later in September, when it returns to the morning sky in Leo. At that time, the comet will be low in the east at early dawn. You’ll probably need a small telescope to spot it. I’m comet crazy, so I’ll be setting my alarm at the earliest opportunity and reporting my observations (and others) to the blog on regularly around that time. Stay tuned.

    1. astrobob

      Comet Honda will once again pass near the Earth in Feb. 2017 but will certainly not crash. The closest it will come will be a bit farther than it was this past August.

  5. yash

    Hi I’m from INDIA, on 17th of this month at 6.45am i saw a thing in sky which look like a comet by appearance. I was very fascinated to know some details abt that but i couldn’t find any details regarding tht in any of the sites……

    1. astrobob

      If it was daylight and the “comet” was easy to see, you probably were watching a distant airplane vapor contrail.

        1. astrobob

          The only comet visible at the time you describe is Comet Lovejoy, but on that date it was only 2 degrees from the sun a few minutes before sunrise and would have been extremely faint and difficult to see. Where it’s much better placed in the southern hemisphere, most observers weren’t able to see it with at that time except with a telescope. Can you describe it in more detail? What did the head of the comet look like, how long was the tail?

          1. yash

            well it looked like a hot ball thrown with enormous speed having a tail near abt to 10 to 14 times of the diameter of the head (as per the view)

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