2017 binocular comets Archives

May 18, 2017May 18, 2017 by David Dickinson

Comet V2 Johnson Takes Center Stage

Comet V2 Johnson from February 21st, 2017. Image credit and copyright: John Purvis

Had your fill of binocular comets? Turns out, 2017 may have saved the best for last. The past few months has seen a steady stream of dirty snowball visitations to the inner solar system, both short term periodic and long term hyperbolic. First, let’s run through the cometary roll call for the first part of the year: There’s 41P Tuttle-Giacobini-Kresák, 2P/Encke, 45P Honda-Markov-Padjudašáková, C/2015 ER61 PanSTARRS and finally, the latecomer to the party, C/2017 E4 Lovejoy.

Next up is a comet with a much easier to pronounce (and type) name, at least to the English-speaking tongue: C/2015 V2 Johnson.

It would seem that we’re getting a year’s worth of binocular comets right up front in the very first half.

Discovered by the Catalina Sky Survey by astronomer Jess Johnson on the night of November 3^rd 2015 while it was still 6.17 astronomical units (AU) distant at +17^th magnitude, Comet V2 Johnson is currently well-placed for mid-latitude northern hemisphere viewers after dusk. Currently shining at magnitude +8 as it glides through the umlaut-adorned constellation Boötes the Herdsman, Comet V2 Johnson is expected to top out at magnitude +6 in late June, post-perihelion.

The path of Comet C/2015 V2 Johnson through the inner solar system. Credit: NASA/JPL

Part of what’s making Comet V2 Johnson favorable is its orbit. With a high inclination of 50 degrees relative to the ecliptic, it’s headed down through high northern declinations for a perihelion just outside of Mars’ orbit on June 12^th. Though Mars is on the opposite side of the Sun this summer, we’re luckily on the correct side of the Sun to enjoy the cometary view. Comet V2 Johnson passed opposition a few weeks ago on April 28^th, and will become an exclusively southern hemisphere object in late July as it continues the plunge southward.

This is likely Comet V2 Johnson’s first and only journey through the inner solar system, as it’s on an open ended, hyperbolic orbit and is likely slated to be ejected from the solar system after its brief summer fling with the Sun.

This week sees Comet V2 Johnson 40 degrees above the eastern horizon in Boötes as seen from latitude 30 degrees north, one hour after sunset. The view reaches its climax on June 6^th near the comet’s closest approach to the Earth, with a maximum elevation of 63 degrees from latitude 30 degrees north, one hour after sunset.

The path of Comet V2 Johnson as seen from latitude 30 degrees north, 45 minutes after sunset from mid-May to late June. The constellation positions are for the beginning date. Credit: Starry Night Edu. software.

The comet also sits just 5 degrees from the bright -0.05 magnitude star Arcturus on June 6th, providing a good guidepost to find the fuzzball comet. July sees the comet cross the ecliptic plane through Virgo, then head southward through Hydra and Centaurus. Another interesting pass occurs on the night of July 3^rd, when the Moon just misses occulting the comet.

Comet V2 Johnson’s celestial path through August 1st. Credit: Starry Night Edu. Software.

Here are some key dates with destiny for Comet V2 Johnson through August 1^st. Unless otherwise noted, all passes are less than one degree (two Full Moon diameters) away:

May 19^th: passes near +3.4 magnitude Delta Bootis.

June 5^th: Closest approach to the Earth at 0.812 AU distant.

June 12^th: Perihelion 1.64 AU from the Sun.

June 15^th: Crosses into the constellation Virgo.

June 21^st: Crosses the celestial equator southward.

June 26^th: Passes near the +4 magnitude star Syrma.

July 1^st: Passes near (30″!) the +4.2 magnitude star Kappa Virginis

July 3^rd: The waning gibbous Moon passes two degrees north of the comet.

Comet V2 Johnson vs Kappa Virginis and the Moon on July 3rd. Note: the graphic is a (very) idealized version of the comet! Credit: Starry Night Edu.

July 5^th: Crosses the ecliptic southward.

July 17^th: Crosses into the constellation Hydra.

July 22^nd: Passes 2.5 degrees from the +3.3 magnitude star Pi Hydrae.

July 28^th: Crosses into the constellation Centaurus.

V2 Johnson light curve — The projected light curve for Comet C/2015 V2 Johnson. The purple vertical line marks perihelion, and the black dots are actual brightness observations to date. Image credit: adapted from Seiichi Yoshida’s *Weekly information About Bright Comets*.

Binoculars and a good finder chart are your friends hunting down a comet like V2 Johnson. We like to start our search from a nearby bright star, then slowly sweep the field with our trusty Canon 15×45 image-stabilized binoculars (hard to believe, we’ve had this amazing piece of astro-tech in our observing arsenal for nearly two decades now. They’re so handy, picking up a pair of “old-tech” none stabilized binocs feels weird now!). An +8^th magnitude comet will look like a fuzzy globular cluster which stubbornly refuses to resolve when focused. A wide-field DSLR shot should also tease V2 Johnson out of the background.

Comet V2 Johnson from May 3rd. Image credit and copyright: Hisayoshi Kato.

The next week is also ideal for evening comet-hunting for another reason, as the New Moon (also marking the start of the Islamic month of Ramadan) occurs on May 25th, after which, the light-polluting Moon will begin to hamper evening observations.

It’s strange to think, there are no bright comets on tap for the remainder of 2017 after V2 Johnson, though that will likely change as the year wears on.

In the meantime, be sure to check out Comet V2 Johnson, as it makes its lonesome solitary passage through the inner solar system.

April 3, 2017April 4, 2017 by David Dickinson

Surprise: Comet E4 Lovejoy Brightens

Credit and copyright: The Virtual Telescope Project

Had your fill of binocular comets yet? Thus far this year, we’ve had periodic comets 2P/Encke, 45P/Honda-Mrkos-Pajdušáková and 41P/Tuttle-Giacobini-Kresák all reach binocular visibility above +10^th magnitude as forecasted. Now, we’d like to point out a surprise interloper in the dawn sky that you’re perhaps not watching, but should be: Comet C/2017 E4 Lovejoy.

If that name sounds familiar, that’s because E4 Lovejoy is the sixth discovery by prolific comet hunter Terry Lovejoy. Comets that have shared the Lovejoy moniker include the brilliant sungrazer C/2011 W3 Lovejoy, which amazed everyone by surviving its 140,000 kilometer (that’s about 1/3 the Earth-Moon distance!) pass near the blazing surface of the Sun on December 16^th, 2011 and went on to be a great comet for southern hemisphere skies.

The path of Comet E4 Lovejoy through the end of April. Credit: Starry Night.

Unfortunately, E4 Lovejoy won’t get quite that bright, but it’s definitely an over achiever. Shining at a faint +15^th magnitude when it was first discovered last month on March 9^th, 2017, it has since jumped up to +7^th magnitude (almost 160 times in brightness) in just a few short weeks. We easily picked it out near the +2.4 magnitude star Enif (Epsilon Pegasi) on Saturday morning April 1^st in the pre-dawn sky. E4 Lovejoy was an easy catch with our Canon 15×45 image-stabilized binocs, and looked like a tiny +7 magnitude globular (similar to nearby Messier 15) that stubbornly refused to snap into focus. In fact, I’d say that E4 Lovejoy was a much easier comet to observe than faint Comet 41P/Tuttle-Giacobini-Kresák, which made its closest pass 0.142 Astronomical Units (21.2 million kilometers) from the Earth on the same day.

Comet E4 Lovejoy from the morning of April 4th. Image credit and copyright: Gerald Rhemann/Sky Vistas.

Prospects and Prognostications

E4 Lovejoy will remain an early pre-dawn object through April for northern hemisphere observers as it glides through the constellations Pegasus, Andromeda and Triangulum. If current predictions hold true, the comet should reach a maximum brightness of magnitude +6 around April 15^th. On an estimated ~ 600,000 year orbit, Comet E4 Lovejoy may be a first time visitor to the inner solar system, and its current outburst may also be short-lived. In fact, there’s lots of speculation that Comet E4 Lovejoy may disintegrate altogether, very soon. Plus, the Moon is headed towards Full next week on April 11^th, making this week the best time to catch a glimpse of this fleeting comet.

The projected light curve for Comet E4 Lovejoy. Credit: Seiichi Yoshida’s *Weekly Information About Bright Comets*.

And to think: we just missed having a bright naked eye comet! That’s because Comet E4 Lovejoy very nearly passed through the space that the Earth will occupy just next month. In fact, the comet passed just 0.11 AU (17 million kilometers) interior to the Earth’s orbit on March 22^nd, 2017. Had it done the same on May 4^th, it would have been 5 times closer and 25 (about 3 to 4 magnitudes) times brighter!

The orbit of Comet E4 Lovejoy through the inner solar system. NASA/JPL

A tantalizing miss, for sure. Comet C/2017 E4 Lovejoy reaches perihelion at 0.5 AU (77.5 million kilometers) from the Sun on April 23^rd, and passed 0.6 AU (93 million kilometers) from the Earth on March 31^st. This week, it will be moving through Pegasus at a rate of about four degrees (8 Full Moon diameters) a day. With an orbital inclination of 88 degrees, Comet E4 Lovejoy’s path is very nearly perpendicular to the ecliptic path traced out by the Earth. The comet swung up from the south during discovery, and is now headed northward towards perihelion.

Here are some key dates for Comet C/2017 E4 Lovejoy to watch out for in April:

April 7^th: Passes less than one degree from the +3.5 magnitude star Sadal Bari (Lambda Pegasi).

April 9^th: Passes less than 10′ from the +2.4 magnitude star Scheat (Beta Pegasi).

April 13^th: Crosses into the constellation Andromeda.

April 19^th: Photo-op, as the comet passes 4 degrees from the Andromeda Galaxy M31.

April 22^nd: Passes between the +2^nd magnitude star Mirach and the +4^th magnitude star Mu Andromedae.

April 27^th: Passes five degrees from the Pinwheel Galaxy M33.

April 28^th: Crosses into the constellation Triangulum.

Looking to the northeast at 6 pm local on the morning of April 19th from latitude 30 degrees north. Credit: Stellarium.

Teaser for 2017 Comets

We’re barely a quarter of the way through 2017, with more cometary action to come. We’re expecting 2015 ER51 PanSTARRS (May), and 2015 V2 Johnson (June) to reach binocular visibility. You can read about comets, occultations, and more in our guide to 101 Astronomical Events for 2017, a free e-book from Universe Today.

We’re due for the next big one, for sure. It always seems like there’s a “Great Comet” per every generation or so, and its been 20 years now since comets Hale-Bopp and Hyakutake graced northern skies.

Binoculars are the best tool for observing comets like E4 Lovejoy, as they offer a generous true (i.e. not inverted) field of view. A good finder chart and dark skies also help. We like to find a good nearby ‘anchor’ object such as a bright star, then hop into the suspected comet area and start sweeping.

One thing’s for sure: we need more comets with names like Lovejoy… if nothing else, it’s much easier to pronounce, and us science writers don’t have to keep hunting through the ‘insert’ menu for those strange letter symbols that grace many of these icy denizens of the Oort Cloud as they pay a visit to the inner solar system.

March 20, 2017 by David Dickinson

Catch Comet 41P Tuttle-Giacobini-Kresák At Its Best

Comet 41P glows green (left) and shows its true coma and just the hint of a stubby tail in the negative (red) image (right) from March 19th. Image credit and copyright: Hisayoshi Kato

Miss out on comet 45P Honda-Mrkos-Pajdušáková? Is Comet 2P Encke too low in the dawn sky for your current latitude? Well, the Universe is providing us northerners with another shot at a fine binocular comet, as 41P Tuttle-Giacobini-Kresák glides through Ursa Major this week.

As seen from 30 degrees north, Comet 41P Tuttle-Giacobini-Kresák (sometimes called “Comet 41P” or “Comet TGK”) starts the last week of March about 40 degrees above the NE horizon at 9PM local. It then makes the plunge below 30 degrees elevation on April 1st for the same latitude at the same time. At its closest on April 5th, the comet will be moving at two degrees a day (the width of four Full Moons!) as seen from the Earth as it slides down through the snaky constellation of Draco.

The path of Comet 41P from March 20th through April 20th. Credit: Starry Night.

The comet reaches an elevation of 10 degrees for evening viewers around April 15^th, and passes 10 degrees north of another up and coming binocular comet C/2015 V2 Johnson right around the same date. After early April, your odds get better to see Comet 41P Tuttle-Giacobini-Kresák high in the sky at its upper culmination past local midnight towards dawn.

There’s another reason to try and recover this comet this week, as the Moon is now a waning crescent headed towards New on March 28th. From there, the waxing Moon begins to interfere with cometary observations as it heads towards the Easter Full Moon on April 11^th, pushing efforts to recover and follow the comet towards pre-dawn hours.

First discovered by astronomer Horace Tuttle 1858, the comet was independently recovered by Michel Giacobini in 1907 and L’ubor Kresák in 1951 and its periodic nature was uncovered.

Note: We believe that the “May 3^rd, 1858” date given for the discovery of this comet around ye ole Web is in fact, erroneous, as both Stellarium and Starry Night put the comet just a few degrees from the Sun on this date! Perhaps both programs are wrong looking that far back in time… but they’re both exactly wrong. Perhaps a bit of astronomical detective work is in order? More to come!

Due for a revision? Here’s the position of Comet 41P Tuttle-Giacobini-Kresák on the oft quoted discovery date of May 3rd, 1858… just 8 degrees from the Sun! Credit: Stellarium.

Orbiting the Sun once every 5.4 years, this is the 29th perihelion return of the comet since its discovery in 1858. The comet’s orbit takes it from 5.1 AU, out to near the orbit of Jupiter, to a perihelion just 0.13 AU outside the orbit of the Earth. This year’s passage is nearly as close as the comet can approach the Earth, with solar opposition also occurring on April 5^th. The comet’s orbit is inclined about nine degrees to the ecliptic plane. Think of the comet zipping down over the northern hemisphere of the Earth, reaching perihelion as it heads from north to south, then headed back out over the southern hemisphere.

Currently at +9^th magnitude, the comet should flirt with naked eye visibility of magnitude +6 in early April. This comet is also worth watching, as it’s known for periodic outbursts. Flashback to 1973, and Comet 41P Tuttle-Giacobini-Kresák made an easy naked eye apparition of +4. This is also the closest approach of Comet 41P Tuttle-Giacobini-Kresák near the Earth in our lifetimes, and the closest in the two century span from 1900 to 2100.

The projected light curve for Comet 41P Tuttle-Giacobini-Kresák. The pink line denotes perihelion, at the black dots mark recorded magnitude estimates. Adapted from Seiichi Yoshida’s *Weekly Information About Bright Comets*.

Arecibo did ping 41P Tuttle-Giacobini-Kresák in early March, but probably won’t image the comet near perihelion due to its northerly declination (Arecibo is only partially steerable). They did, however nab a great animation of the twin lobbed Comet 45P Honda-Mrkos-Pajdušáková on February 12^th:

An amazing view: Comet 45P Honda-Mrkos-Pajušáková pinged by Arecibo radar last month. Credit: Arecibo/USRA

That makes two, bi-bulbous comets, if you include Comet 67P Churyumov-Gerasimenko. Are twin-lobbed comets in fact as common as comet-hunters with umlauts in their name?

Here are some key highlight events for Comet 41P Tuttle-Giacobini-Kresák to watch out for. Close passes are less than one degree unless otherwise noted:

March 21^st: Photo-op: passes between M108 and M97 the Owl Nebula
March 29^th: passes into Draco
April 2^nd: Passes near the 3.6 magnitude star Thuban (Alpha Draconis)
April 5^th: Passes just 0.15 AU (23.2 million kilometers) from the Earth at 13:30 UT.
April 7^th: passes just 22 degrees from the north celestial pole at declination 68 degrees north.
April 11^th: reaches perihelion at 1.05 AU (162.7 million kilometers) from the Sun.
April 18^th: passes the 2.7 magnitude star Rastaban (Beta Draconis)
April 20^th: passes into the constellation Hercules

The comet vs two Messier objects: the view on March 22nd at 12:00 UT. Credit: Starry Night

Observing comets is an exercise in patience, as that quoted magnitude is often smeared out over an extended area. Dark skies and a good star chart are key. I like to use binoculars when hunting for comets brighter than +10^th magnitude, as it gives you a true (un-inverted both up/down and left to right) view, coupled with a generous field of view.

Comet 41P Tuttle-Giacobini-Kresák from March 15th. Image credit and copyright: Wendy Clark.

If Comet 41P Tuttle-Giacobini-Kresák outperforms into the +6^th magnitude range or brighter, it could become a fine target to image with foreground objects. We’re already seeing some amazing images streaming in, with more to come as perihelion approaches.

Other binocular comets to watch for in 2017 include C/2015 ER61 PanSTARRS (May) and C/2015 V2 Johnson (June).

If Comet 41P Tuttle-Giacobini-Kresák performs at or above expectations (and if no great “comet(s) of the century show up!) it could be the best binocular comet of 2017. Don’t miss it!

-Send those images to Universe Today’s Flickr page.
-Be sure to read about the brightest comets of the year and more in our 2017 Astronomical Guide, free from Universe Today.