Wassup With Comets Hergenrother, L4 PanSTARRS And S1 ISON

168P/Hergenrother with its short but sweet tail pointing southeast continues to head north into Andromeda in the coming nights. This photo was taken on October 16, 2012 from Austria. Credit: Michael Jaeger

With Comet 168P/ Hergenrother still bright and perfectly placed high in the southeast at nightfall, I wanted to share an updated map for amateur astronomers with 6-inch and larger telescopes who’d like to track the comet. At around magnitude 9.5, it’s still the brightest fuzzball in the fall sky. For the next couple weeks, 168P will track from northern Pegasus into Andromeda as it slowly fades. Put it on your list of autumn night sky targets and you won’t be disappointed.

Comet Hergenrother’s position in Pegasus and Andromeda at 10 p.m. (CDT) nightly beginning Oct. 18. Stars are shown to magnitude 9.5 with the brighter ones labeled. Right click the image and save, then print a copy you can use at the telescope. North is up. Created with Chris Marriott’s SkyMap software

If you don’t see the comet this time around, you’ll have to wait 7 years for its return. Hergenrother is a short period  or periodic comet – one that orbits the sun in fewer than 200 years. That’s what the “P”  stands for in its name. Since its discovery in 1998 by American astronomer Carl Hergenrother, this feathery visitor is making its third observed trip. About 265 numbered periodic comets have been discovered to date. Unnumbered periodic comets number nearly 250.

Next in our comet lineup is comet C/2011 L4 PANSTARRS.  The “C” indicates a long-period comet or one that orbits the sun in more than 200 years. Two hundred? That’s nothing. L4 Pan-STARRS’s period is estimated at 110,000 years. Seeing it’s a once-in-a-lifetime experience for sure.

Comet C/2011 L4 Pan-STARRS sprouts a short tail in this photo taken on Sept. 9, 2012. Credit: Michael Mattiazzo

Right now, the comet looks like a small, dense cotton wad of light in southern Libra visible only from the southern hemisphere low in the west during early evening hours.

Pan-STARRS has plateaued at a dim 11.5 magnitude for the past few weeks, but is expected to slowly brighten through fall and winter. Northern hemisphere observers will have to be patient. We won’t spy it till next March because the comet will either be too near the sun or too low in the sky.

On March 9, 2013 , L4 PANSTARRS passes just 28 million miles from the sun. In the days before and after, solar heating will furiously vaporize ice and dust from its outer crust causing the comet to quickly brighten and develop a substantial tail. A few days later it pops into the evening sky and could shine as bright as -1 magnitude or nearly the equal of Sirius, the brightest star. That’s what the predictions say anyway. More information and a sky chart HERE.

Artyom Novichonok and Vitali Nevski at their observatory. The two discovered the comet in photos taken a half hour before dawn on Sept. 21, 2012.  Copyright: Vitali Nevski and Artyom Novichonok

At least we can see L4 Pan-STARRS with an 8-inch or larger telescope. Comet C/2012 S1 ISON at 17th magnitude dips way below the limit, though amateur astronomers using larger instruments and digital cameras have taken pictures of it. ISON was scooped up by Russian amateur astronomers Vitaly Nevski and Artyom Novichonok in the course of the work for the International Scientific Optical Network (ISON) Survey from near Kislovodsk, Russia on Sept. 21. I hope the two are eventually recognized for their discovery by having their names penned to the comet instead of a survey acronym. Other comets discovered during surveys have received the discoverer’s name. Why not this one?

S1 ISON creeps very slowly across the constellation Cancer in the morning sky this month and next and won’t become visible in typical telescopes until next September. On November 28, 2013, the comet passes just 800,000 miles from the sun. If it survives the encounter, it could become brighter than Venus and be visible in broad daylight. A few days after its near-death experience, ISON swiftly moves northward, becoming visible in both evening and morning skies.

Look closely and you’ll see a small, fuzzy coma around Comet C/2012 S1 ISON’s star-like nucleus in this photo taken Oct. 17, 2012. Credit: Rolando Ligustri

Ernesto Guido and the team of amateur astronomers at the Remanzacco Observatory in Italy have observed a large amount of activity in the comet’s nucleus this fall despite it being 558 million miles from the sun or farther than Jupiter. Mike Mattei, another amateur astronomer, reports that Earth will pass under the incoming leg of ISON’s orbit. If the comet is large and active, he predicts we could see an increase in meteor activity around January 14-15, 2014 spawned by dust cooked off the comet nucleus. Isonids anyone?

Though I’ve heard it’s possible ISON could rival the full moon’s brightness and become one of history’s “Great Comets” when it appears in both morning and evening skies in early December, I’m going to play the conservative card. I’ve been burned by a few comets that haven’t lived up to expectations, and besides, these creatures are unpredictable anyway. That’s their charm. It could easily be fainter or brighter, though the latter is preferable by far. More on the S1 ISON including sky charts HERE.

17 Responses

  1. Steven

    I’m new here, but what an amazing website. I know quite a lot of astronomy sites, but this one stands out by far when it comes to the enormous amount of interesting and up to date information, together with photos, graphs etc. I’m off to read older posts now, but please keep up the good work!

  2. Many thanks for the update! Your charts are the best I’ve found for Hergenrother. I’ll keep my fingers firmly crossed for PANSTARRS and ISON. FWIW, the story I heard on ISON is that other observers in the network had also observed the comet independently by the time the report from Nevski and Novichonok was in, and that’s why the comet is named for the network and not those two specifically. Maybe someone can confirm this? It is kind of a bummer that their names aren’t on the comet, but I doubt if anyone will forget that they found it first–especially if it brightens up as predicted.

    1. astrobob

      Hi Matt,
      Thanks very much! I wanted to make the charts as useful as possible. You’re the first to mention that other observers were involved in the discovery. As far as I’ve been able to tell, Artyom and Vitaly were the first. You can read their account here: http://bit.ly/S8F9XK It’s near the bottom of the page. Do you know the source saying multiple observers discovered it?

    1. astrobob

      Hi Wday,
      Glad you’re enjoying the blog. Thanks for writing. I always post it Twitter at astrobob_bk or you can just hit the blue Twitter button in the upper right corner of the blog to subscribe.

  3. lynn

    Bob your becoming quite a star ( excuse the pun) lol but I have been reading your blog well over a year now and your the best so please hurry up with that book 🙂 your knowledge and dedication is outstanding 🙂

  4. MBZ

    Thanks Bob, great chart. Maybe I’ll get lucky tomorrow and steal some time.
    Sure hope s1-ison performs next year, haven’t had a thrilling comet experience since Hyakutake.

  5. MBZ

    No, but I wish I had. Altho’ it was a pretty sight, it didn’t have the color and magic of Hyakutake. The entire H.B. event was spoiled for me by the ridiculous claims of alien ships, Planet X, mass suicides.
    I had the distinct displeasure of knowing (not personally, but through a DJ friend) C. Shramek, the nut who started the whole myth. He called looney Art Bell… And the rest is history.
    Perhaps you were blissfully ignorant of all that baloney. Sadly, I was not, and ended up spending far too much time disavowing…something you seem forced to do here often 😉
    You are quite a gentleman.

    1. astrobob

      You’re the first person I’ve met involved or touched by the “dark side” of the story on Hale-Bopp. What a tragedy that people committed suicide over such a thing instead of enjoying the comet for what it was – a real spectacle. Hale-Bopp is the one that hands go up for when I ask if anyone’s ever seen a comet. I enjoyed Hyakutake almost as much. It got bigger and ghostlier all the time near Arcturus late at night. The tail was the longest I’d ever seen when it swung ’round to the west in early spring.

  6. ChemE


    Hergenrother recently broke up. We should expect something similar may happen with ISON and PanSTARRS. I am a Chemical Engineer and my research tells me comet nuclei are NOT ICE AND SNOW they are DARK MATTER. Each Nuclei is its own Low Energy Nuclear Reactor (LENR) and they are very dangerous when they breakup. Dark Matter can orbit THROUGH and AROUND regular matter and can trigger massive CME’s in the sun.
    We need to be prepared for potential massive solar flares at the end of 2012 and 2013.
    Stewart Simonson

    1. astrobob

      Your ideas concerning comet nuclei are frankly incorrect. There is no evidence to support your bizarre conclusions.

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