Bright Comet Prospects for 2017

Comet lovers have much to look forward to in 2017 with six potential binocular comets and at least two others for modest backyard telescopes.

Blue-green Phantom

7th-magnitude 45P/Honda-Mrkos-Pajdusakova cut a fine figure on December 28th with a narrow gas tail pointing east.
Gerald Rhemann

If you don't own binoculars, get a pair soon. I've gone over my list, checked it thrice, and come up with six likely binocular comets making appearances in 2017. At least one of these could reach naked-eye visibility.

The first is returning periodic comet 45P/Honda-Mrkos-Pajdusakova, currently painfully low in the southwestern sky in late evening twilight but mustering a healthy magnitude +7. Several observers have reported seeing it with binoculars this past week, including amateur Scott Harrington of Arkansas who spotted it in a pair of 7×35s.

Due to clouds, my last observation was made two weeks ago. Then the comet appeared bright and well-condensed with a beautiful aqua-hued coma in a 15-inch reflector magnifying 64×.

Binocular Bonanza

As reported in an earlier blog, Comet 45P/H-M-P will show best in the early morning just before the start of dawn in February, when it could top out around magnitude +6.5. It will also be much easier to see, streaking from Hercules through Boötes over just a couple days as it makes an exceptionally close approach to Earth.

Finder Chart Comet 45P/

45P/Honda-Mrkos-Pajdusakova arcs across Capricornus this month; it should remain visible very low in the southwestern sky until disappearing in the twilight glow around mid-month. The comet returns to view at dawn in early February. Click the map for a larger chart you can print out. Click here for a February–March map. Positions are plotted at 3-day intervals at 0h UT.
Sky & Telescope

I hope you like getting up early because this week and early next will be your last chances to catch 8th-magnitude comet NEOWISE (C/2016 U1). Discovered last fall, this initially diffuse object has steadily brightened to become more compact and luminous to the point that it's now observable in small telescopes and even binoculars from a dark sky.

Get out there soon! The comet is sinking fast into the dawn glow, with only about a week left in its northern apparition. In late February, it might be glimpsed again around 12th magnitude low in the west at dusk but only from the southern hemisphere. With an orbital period of thousands of years, no one alive today will witness its next return. Sniff.

Farewell to This Fuzzball

Comet NEOWISE (C/2016 U1) still looks much as it did when this photo was taken on December 9th — a round ball of fuzz with a brighter condensation at center. Time is running short to view the comet!
Michael Jaeger

C/2016 U1 responds well to a Swan Band filter, an accessory every serious comet observer should have. It blocks unwanted light while enhancing fluorescing molecular carbon gases in a comet's coma. Some comets produce a lot of gas and respond very well to the filter; others are less gassy and show little change in contrast. For a gassy comet at low altitude, the filter can be make the difference between seeing it or not.

Hurrying from Earth

C/2016 U1 drops south rapidly in the coming days and soon disappears from view. You'll need a good eastern horizon to spot the comet as it crosses from Ophiuchus into Serpens. Positions plotted daily with stars to magnitude +8. This map and the other "black on white" maps show the sky from latitude +40° N. The comet is plotted at 1-day intervals. Click to enlarge, then save and print out for use at the telescope.
Source: Chris Marriott's SkyMap software with additions by the author (all B&W maps)

Periodic comets, those that lap the Sun in fewer than 200 years, are well represented this year. Next in line is the dashing little fuzzball 2P/Encke, which completes an orbit in a hurry, just 3.3 years. Encke always begins its apparition as a faint, diffuse mist but wastes no time brightening and compacting into a fine little comet suitable for small telescopes.

Encke Meets the Circlet

Watch for 2P/Encke to brighten to binocular visibility as it loops around the Circlet asterism in Pisces during early evening hours in February and March. Positions plotted daily with stars to magnitude +9.5.
Source: Chris Marriott's SkyMap software

The comet was recently snared by visual comet observers in December, but it still shines wanly at magnitude +12 at this writing. Watch for it to brighten to magnitude +9 by mid-February as it cracks the whip around the Circlet asterism in Pisces at nightfall. Soon after, Comet Encke plunges south and becomes lost in evening twilight by early to mid-March even as it swells to a predicted magnitude of ~6.5. Just so we don't lose count, that's already three binocular comets and we're barely halfway through our list.

Keep 'em Comin'

Humble Beginnings

C/2015 ER61 (PanSTARRS) may not look like much now (this photo taken December 8), but come perihelion on May 10th, it could become visible in binoculars low in the east at the start of dawn.
Joseph Brimacombe

Eager for more? Pull closer to the table. The next comet, PanSTARRS (C/2015 ER61), has created a flurry of excitement with some estimating its peak magnitude as bright as +2. Discovered as an asteroid in 2015, it was later shown to exhibit a coma and renamed as a comet. Most sources I've checked, including Seiichi Yoshida's excellent Weekly Bright Comets and JPL's Horizon site, put C/2015 ER61 at magnitude +7 from mid-April through mid-May. No complaints here. Any comet visible in binoculars is a gift, and every one of them looks even more amazing in a telescope.

Ecliptic Hugger Climbs North in 2017

C/2015 ER61's path parallels the ecliptic throughout the year. It will be brightest in northern mid-spring but low in the eastern sky at the start of dawn throughout its apparition. Positions plotted at 5-day intervals with stars to magnitude +7.
Source: Chris Marriott's SkyMap software

Still, some may struggle to find this cotton ball. Why? C/2015 ER61 has a serious altitude problem for observers at mid-northern latitudes throughout its apparition. The comet tracks along the ecliptic never far behind the Sun. This month, the 30″ diameter, 13th-magnitude comet creeps from Libra into Scorpius, keeping observers at bay until the very start of dawn, when it finally reaches a somewhat reasonable height above the horizon. When brightest in May, it will be crossing from Aquarius to Pisces.

Comet With Promise

Comet Johnson (C/2015 V2) is currently well-placed in the morning sky for amateur observation. A short tail pointing northwest is visible in 10-inch and larger scopes.
Chris Schur

I've got high hopes for a relative newcomer to the comet scene, Johnson (C/2015 V2), which may peak around magnitude +6.5 in early June as it slides down the eastern side of Boötes high in the southern sky before the mosquitoes return. Currently at magnitude +11.5, 1′ in diameter and moderately condensed, this comet is warming up for its spring performance in the morning sky in northern Boötes. An 8-incher should coax it into view using magnifications of 100× and higher.

Right Time, Right Place

Comet Johnson (C/2015 V2 ) should put on a nice evening show during May and June as it races to a June 12th perihelion. Positions plotted at 5-day intervals with stars to magnitude +8.
Source: Chris Marriott's SkyMap software

By the way, if you lack the software to create a comet path, you can always download the latest version of the free program Stellarium for Windows or Mac and pinpoint this and any other comet's position one night at a time. To ensure you have all the stars you need (down to magnitude 14 and fainter), click on the Configuration tab on the left side of your screen, select Tools, then download Star Catalog Updates.

Update March 16, 2017: Use the finder chart for Comet T-G-K here (the ticks are for 9 p.m. EDT = 1h UT on the following date). The earlier chart that appeared with this article, which is also printed in the May 2017 Sky & Telescope, is significantly wrong due to a change in the ephemeris.

I saved what might become the brightest comet for last, 41P/Tuttle-Giacobini-Kresak. We touched on this one in a blog last November as one of the three periodic comets that are making extremely close passes of Earth in the next two years. Come April, as it tears across the northern circumpolar sky, it may max out at magnitude +6 and become faintly visible with the naked eye under rural skies. While that's exciting enough to contemplate, this comet is known for outrageous outbursts. Twice in 1973 it underwent 10-magnitude eruptions! More recently, in December 2001, it shot up three magnitudes unexpectedly. Watch out for this live wire!

Fainter Fuzzies

Favorable Return in Scorpius

71P/Clark may brighten to magnitude +10 in late spring as it winds through Ophiuchus and Scorpius. Positions plotted every 5 days with stars to magnitude +9.5.
Source: Chris Marriott's SkyMap software

As if that's not enough, two other fainter comets will help to fill in any gaps, making sure no one goes home cometless in 2017. They're both periodic: 71P/Clark and 24P/Schaumasse. Clark could reach magnitude +10 from mid-June to early July as it describes a lazy S through Scorpius. Southern Hemisphere observers are favored, but the comet will still be high enough to catch from mid-northern latitudes during its brightest period. In late May, watch for it to pass just 2° east of Antares.

Modest Comet Wraps Up the Year

Another one for early birds. 24P/Schaumasse returns after 8.2 years, gliding from eastern Leo through Virgo in the wee hours of November and December. Positions are daily with stars to magnitude +9.
Chris Marriott's SkyMap software

24P/Schaumasse, which returns every 8.2 years, rounds out 2017 with a morning appearance at magnitude +10–10.5 in November and December while tracking across the "Cup" of Virgo, home to hundreds of galaxies, including this mobile lookalike.

Potential Naked-Eye Comet

Comet 41P/Tuttle-Giacobini-Kresak may reach naked-eye visibility (magnitude +6) in Ursa Major from a dark site in early April 2017. We see it here on December 23, 2000.
Michael Jaeger

Finally, let's not forget the quixotic, exotic and alphabetic 29P/Schwassmann-Wachmann, known for frequent outbursts that can take it from magnitude +14 or +15 to +10 or +11 overnight. You can watch for it beginning in May and watch all the way through year's end as it crawls across northern Capricornus into Aquarius.

No matter what your instrument — naked eye, binoculars, or telescope — 2017 promises to be a bountiful year for comet lovers. And that doesn't even include new ones that are just waiting to be discovered!

24 thoughts on “Bright Comet Prospects for 2017

  1. George Gliba

    Happy New Year Bob,

    Observed comet 45P/Honda-Mirkos-Pajdusakova at 6:30 PM EST last might. It was near
    the star theta Cap and was fairly easy to see in 12×63 bimoculars in excellent skies with
    good horizons at Mountain Meadows, West Virginia. A short tail was also noticed. It was
    very lovely seen just above the distant mountains. It was about 7th magn. and had a short
    dust tail.

    G.W, Gliba

  2. P.Michael-Hutchins

    I only read this piece twice, but I didn’t find anything that is actually likely to be binoculars-visible, unless his horizon is that that’s available from the top of Mt. Washington.
    Given that, I can’t see why anyone thought that “Bright Comet Prospects for 2017” was a reasonable title for this article. I’m very disappointed, and really didn’t need to waste my time getting there.

    1. Bob KingBob King Post author

      Any comet 7th magnitude or brighter is easily within range of ordinary 10×50 (or even 7×35) binoculars for observers under reasonably dark skies unless it’s close to the horizon. There have been numerous observations of 45P/H-M-P in binoculars the past few weeks and even some of U1 NEOWISE. Many amateurs, including myself, routinely see mag. 8.0 comets in 10×50 binoculars – at least when they’re well-placed. Since bright comets are uncommon, one that reaches 6th to 7th magnitude would be considered “bright.” Far more comets are mag. 10 and fainter.

    2. KatMK

      Waa, waa! Unless you are in a deep valley I don’t know what you are complaining about. I spotted P2/Encke with my bare eyes while I was walking my night shift as a security guard. I saw that it was double the size of the planets and knew it had to be a comet or a supernova. And since a supernova is so rare and nothing was on the news about it then it was a comet. This is what has rekindled my interest in sky watching again. Now if I can only remember where I have put the binoculars that I used to have. By the way the easiest way to spot this one is to look to the west just after the sun has set. It appears clear in the sky before the planets and stars begin to shine.

      1. Bob KingBob King Post author

        Hi Kat,

        What you sighted was the planet Venus, not 2P/Encke. The comet’s about 5 degrees SW of Venus and much too faint to see with the naked eye. Binoculars or a telescope will nab it.

    1. Bob KingBob King Post author

      I only plotted U1 NEOWISE into early January because it will be lost in twilight around that time. That’s the reason the path cuts off at the horizon and faces east. If it were visible longer, like the other comets shown, I would have created a longer path with north up. For instance, from latitude +40°, the magnitude +7.7 comet is only 9° high an hour before sunrise in morning twilight on Jan. 8. That shrinks to 3° by Jan. 12. In hindsight, I could have added a few additional mornings and continued the arc to say, the 11th (5° altitude). But even this would be a very difficult observation for most observers.

  3. George Gliba

    It was fairly easy to see with my 12×63 binoculars from near the top of South Branch Mountain
    in Mathias, West Virginia. I would even go so far as to say it was “easy to see”.

  4. George Gliba

    Yes. I will look at it again tonight if it clears. I agree with your comments about
    the visibility of comets in binoculars. I knew a famous NASA scientist who was a
    comet expert who complained that he couldn’t find a fairly bright comet with his
    binoculars. I was tempted to tell him I found that hard to believe, but decide to
    let the comment go unchallenged. The lesson here is the importance of observing

  5. George Gliba

    I was able to observe comet 45P/H-M-P in my 12×63 binoculars this evening but no tail was noticed,
    probably due to the bright moonlight. However, the head of the comet looked brighter and more
    stellar in appearance than three nights ago. The weather conditions on the mountain were somewhat brutal, with a nasty -5 F. windchill. Brrr.

  6. Bob-PatrickBob-Patrick

    Bob King …

    Thank you for another interesting article. The holidays kept me away for a few weeks. Now I hope to be back among your reader fans.

    The last comet I saw was a few years ago from my driveway. Not sure which comet. However, that comet observation was made looking at the western sky through a pair of 25×100 binoculars, mounted on a parallelogram, lying back in a zero gravity lounge chair. My neighbors kept slowing down as they passed my house — a few of them gave me some friendly honks.

    I will have to print your article, make a few notations, and fiddle with my parallelogram setup again. Ha! Ha!


  7. Graham-Wolf

    Hi Bob… great article, and several interesting condidates for looking at, with 50mnm Bonics in dark Lm 6.0 or better skies… OK, maybe “tone it down”to mid 5th Mv. Nice Comet Finder-Charts too. Had already done tghis a few weeks ago in my observing notebook, but great to see you’ve been strategising along similar lines to myself!

    45p/H-M-P continues to pleasantly surprise. Great to hear several of you have seen it over the Xmas New Year period. It’s been passing close to Theta Cap lately. My latest efforts are below.. it went intio outburst just a few days ago, after you wrote this latest article of yours.

    Jan 04.425 UT Mv 7.0 5 arcmin coma DC 5 10x50B Finnie Road Intersection.
    05.427 UT Mv 6.4 6.8 ” ” DC 8 20x80R ” ” ”
    06.426 UT Mv 5.9 5 ” ” DC8/9 10x50B ” ” ”
    07.439 UT Mv 5.9 6 ” ” DC6/7 10x50B Scroggs Hill Summit Trig.

    FINNIE ROADS INTERSECTION= 45.912004 S, 170.355570 E.
    SCROGGS HILL SUMMIT= 45.917015 S, 170.312337 E.

    Took a line from Mars through Venus, then down to Theta Cap (UP-Down, Right-Left for my southern latitudes). I then slightly offset to the comet. For my comparison stars, I used the AAVSO-VSP website and did a Custom Chart (20df MLim 10, around Theta Cap). Solar Elongation was some 26 to 28 deg. Rain showers and storms since then, to say nothing of the pollution of a Full Moon!! Crikey.

    Regards from 46 South, NZ. Graham W. Wolf.

  8. SNH

    Very nice article Bob and thanks for the fame! Since I can see magnitude +8 comets under good conditions in my 7×35 binoculars (bigger binoculars always give a better image, though), I tend to think of any comets between magnitude +7.0 and +9.0 to be “bright”. Any between +5.0 and +7.0 I tend to think of as “really bright” (usually naked eye for me!) while any brighter than +5.0 I tend to think of or label as “super bright”. So I agree with your choice of article title at my current skill level. However, when I was first starting out, comet Lulin was the first comet I saw in my 7×35 binoculars and even though I found it difficult then, it was sixth magnitude and would have been visible naked eye to me now!! It all depends on your observing level and skill star-hopping with binoculars. Good article! Looks like I’m going to see a “ton” of new comets. Yah!

  9. Graham-Wolf

    Hi Bob.

    Looks like 45p will reappear (post conjunction) ~ Feb 10th, next month. From 46 South New Zealand, 45p will be at RA 17:33:22.74, DEC +19:04:48:00, near 93 Herculis. At 5:30 am NZDT, it will be just 2.3 deg above NE horizon from Pikiwara summit trig, overlooking Mt Grand at the back of Abbotsford/Kaikorai. At 5:40am, this increases to 3.75 deg alt, and 5 deg 11 min alt at 5:50am. Sarin/65 Her/HIP 84379 is Mv 3.10, and 55 Oph/HIP 86032 is Mv 2.05. You should find 45p almost exactly halfway between these two stars. At 05:38 NZDT, 45p passes between HIP85917 (Mv 5.65) and HIP 85869 (Mv 7.55) over a 2 minute period. All calculated using Stellarium (released Jan 2nd). The comet should lie some 4 arcmin below HIP 85869 at 5:38am NZDT (NZ terrestrial orientation). The Full Moon rises near the same spot at about the same time 2 days later, so your “window” is really Feb 9 -12th. 10×50 Binocs will do in a ZLM 6 – 6.5 sky, but I’ll be taking my Polarex 20×80 Spotterscope (2 df FOV) with me by foot to the summit. My Meade GOTO ‘scope has been fully reconditioned since I bought it 2nd hand just over a week ago. It runs great at f4 with a SV15 (70af), and 20mm termi-nagler (80af) 1 1/4 inch oculars. Hope this info helps your readers, Bob. Regards from 46 South, NZ. Graham W. Wolf.

  10. Graham-Wolf

    Thanks for your encouragement Bob.
    Always appreciated… astronomy is a pleasure to be freely shared with all.

    For comparison stars next month for 45p/H-M-P, you could do a lot worse, Bob, than a customised AASO-VSP Chart (15df MLim 9 centered on Rasalhague will do superbly). OR… alternatively, make it 15df MLim 9 centred on 93 Her (nearby). 45p on Feb 9 -12, will be (terrestrial orientation) some 10 deg below Rasalgaue (Alpha Oph) and some 5 deg to the left, for Kiwi/Aussie observers. For those in Europe and USA, you’ll need to flip that orientation upside-down, and back to front. If using AAVSO-VSP comparisons, use the reporting code “AC”. If using the HIP (Hipparchus Catalogue) stars, the reporting code is “HP”… as in Hewlett Packard! You’ll also see bright planet Mercury low near the Eastern Horizon… 45p will be ~ N.E.

    For those with Stellarium, WINDOWS SEARCH on “Stellarium”, and enter “ANGLE MODE”. All the function keys will then work fine, by sliding the mouse-pointer to the left hand margin. There are plenty of HIP stars to also compare the comet’s brightness with. To make life easier:- i recommend setting a default site and FOV, so that the Stellarium software boots immediately to it’s “sums” at once. Under Stellarium, enter desired DATE and TIME. Then SEARCH function key, and enter object… in this case 45p/. The cross-hairs will then drift over to the location of the comet against the back-ground stars. Use your mouse-wheel to zoom in to an FOV of say:- 5 deg. This approximate a pair of 10x50B. For a low power telescope, zoom further to ~ 1/2 deg FOV. A good excuse to whip out that 30 or 40mm Plossl / Erfle/ Nagler or ultra-wide what-have-you eyepiece.

    Stellarium V also has a 300 page(!!) pdf manual. It’s easily downloadable from their website. Hope this all helps your readers out there, Bob. Regards from 46 South, NZ. Graham W. Wolf..

  11. Graham-Wolf

    Hello Bob

    Thrilled to report a post-conjunction recovery of 45p (H-M-P) yesterday morning from near Pikiwara Summit at McMaster Road Intersection (~ 5:40am NZDT). Skies cleared about 90 mins beforehand, after an all-night overcast. Used HIP 8872 (Mv6.65), HIP 88590 (Mv 7.40) and HIP 88689 (Mv 8.35) comparisons:- all located within 1.5 df centred on the comet. Also had an AAVSO-VSP Custom Chart (20df MLim 9 centred near Rasalhague) as a “back-up”. Easily identified mercury ~ 7 deg alt in East, and 93 Her, low and a little left of the comet. No tail structure seen.

    Extended a line downwards from Kappa Oph through Rasalhague (Alpha Oph) to the NE horizon. Full Moon had just set in the West, and dawn pollution was starting to limit my LM FOV. Full Moon will be up all night over the next few days. Grrrrr!

    Following data obtained, below. A 20 x 16 arcmin elongated coma seen in 12cm f4 Meade GOTO Newtonian at 50x (96 arcmin FOV), to MLim ~ +9. Comet ~ 1.5 deg above horizon, and above Kaikorai Hill trig with Flagstaff Summit (~ 700m) a further 6km to the rear. No obs today as clouded out all night, and scattered showers all morning, so far!

    FEB 08.695 UT. 20×80 f4 Spotterscope. 20x HIP Comparisons Mv 6.8 20 arcmin coma DC6
    FEB 08.699 UT. 12cm f4 Newtonian 50x HIP Comparisons Mv 6.7 20×16 ” coma. DC6/7

    Regards from 46 South, NZ. Graham W. Wolf

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