Find out when and where to see Comet ATLAS (C/2019 Y4) — and stay tuned to see how bright (or not) this comet gets.

Update April 7, 2020 — Possible Breakup

Photos taken on April 2nd (left) and April 5th with the 0.6-m Ningbo Education Xinjiang Telescope show how the pseudo-nucleus of Comet ATLAS has elongated, indicating a possible fragmentation of its core. 
Quanzhi Ye and Qicheng Zhang 

No, no, no. Say it ain't so. In a recent Astronomical Telegram, astronomers Quanzhi Ye (University of Maryland) and Qicheng Zhang (Caltech) report that photographs taken on April 2nd and April 5th of the comet revealed a marked change in the appearance of its core or pseudo-nucleus from starlike and compact to elongated and fuzzy. A second team of astronomers led by I. A. Steele (Liverpool John Moores University) confirmed the discovery. This change in appearance is "consistent with a sudden decline or cessation of dust production, as would be expected from a major disruption of the nucleus," wrote Zhang and Ye.

In late March, Comet ATLAS displayed a bright, round pseudo-nucleus (left) which has since become elongated and lentil-shaped due to a possible breakup.
José Chambó Bris (left) and Gianluca Masi

An elongated nucleus is often a bad sign and could mean the comet's headed for disintegration much like what happened to Comet Elenin (C/2010 X1) prior to its September 2011 perihelion passage when its core crumbled and the object rapidly dissipated. Addition evidence of ATLAS's breakup comes from an unexpected shift in the direction of its orbital motion caused by "non-gravitational" forces. Fragmentation exposes fresh ice to sunlight which quickly vaporizes. The expanding gases act like a natural rocket engine and gently push the comet from its appointed path.

No cause has been assigned to the fragmentation but recent studies indicate that accelerating spin may play a significant role in nuclear breakups. Jets of gas blasting away from the comet can spin it up, stressing the icy body until it develops cracks that lead to a breakup.

Nick Haigh of Southampton, UK used a 12-inch Skywatcher 300p with an ASI1600MM camera and 682 10-second exposures on April 6th to make this amazing photo showing what appear to be three separate fragments in Comet ATLAS's formerly single nucleus.
Nick Haigh
This photo, compiled from images taken on April 8-9 between 23:40 UT and 01:54 UT, shows additional changes in the comet's nucleus. Nick Haigh

In late March Comet ATLAS began to plateau in brightness; now it appears to be slowly fading. The latest estimates place the comet around magnitude 8.5–9. I strongly encourage you to observe it at every opportunity and share your observations in the comments area. Observers with larger instruments working at high magnification may be able to discern larger nuclear fragments. I spotted the comet with my 15-inch scope in bright moonlight on April 8.14 UT and observed that the brightness and density of the nuclear region had declined from an observation made 10 days ago.

While it's possible ATLAS has lost only a single small fragment and will soldier on to perihelion and naked-eye visibility, the optics aren't looking good at the moment. Full Moon occurs on April 7th but a dark-sky window returns as soon as the 9th. Seize the night to enjoy Comet ATLAS at every opportunity before it (possibly) is no more.


The original article, published March 27th, appears below:

Comet ATLAS (C/2019 Y4)
Comet ATLAS (C/2019 Y4) displays an 8.5-magnitude coma and a short, spiky tail on March 21, 2020. Discovered last December, the comet has brightened rapidly in recent weeks. North is up.
Chris Schur

Not since Comet 46P/Wirtanen passed near the Pleiades star cluster in December 2018 has a naked-eye comet graced the night sky. That may soon change. On December 28, 2019,  astronomers with the automated Asteroid Terrestrial-impact Last Alert System (ATLAS) survey discovered a 20th-magnitude comet in Ursa Major that was subsequently named Comet ATLAS (C/2019 Y4).

Comet ATLAS trajectory
Comet ATLAS’s orbit is tilted 45° with respect to the plane of the planets. Closest approach to the Earth occurs on May 23rd (116.7 million kilometers), prior to its May 31st perihelion.
NASA / JPL Horizons

Once a reasonable orbit was determined, Comet ATLAS proved a close match to the Great Comet of 1844 (C/1844 Y1). Both have periods around 4,000 years, approach within 0.25 astronomical unit (a.u.), or 37.4 million kilometers, of the Sun at perihelion, and are inclined 45° to the ecliptic. These and other orbital similarities were strong enough to conclude that both objects were fragments of a single, much larger comet that broke apart about 5,000 years ago. For all we know there may be additional fragments en route for future appearances.

Comet ATLAS (C/2019 Y4)
Glowing aqua from carbon and cyanogen emissions and sprouting a 15′ long tail, Comet ATLAS passes near Rho (ρ) Ursae Majoris on March 22nd. Its coma has ballooned in recent days to 15′ across, which at its current distance is equal to half the size of the Sun. South is up.
Gerald Rhemann

Because the Great Comet reached 2nd magnitude and grew a 10° tail in January 1845 many of us wondered if its sibling might be capable of doing the same. The answer is a qualified "yes." But one thing is certain — the comet is brightening exponentially.

A Brightening Comet

Back on February 16th, Comet Atlas was a 14th-magnitude wisp 30″ across and barely brighter than the sky background through my 15-inch telescope. Three weeks later on March 6th the coma had grown to about 5′ and become more compact with a magnitude of 11. By mid-March I snared it with a pair of 10×50 binoculars at magnitude 9 from a dark-sky site. Other observers have reported a similar rapid uptick.

To highlight Comet ATLAS's motion, 151 images taken on March 18th were combined to create this video.
Khalid Baheyeldin

How Bright Will Comet ATLAS Be?

While a hundredfold increase in brightness in a month makes a comet lover's heart palpitate, it could also mean that the comet's volatile ices are rapidly vaporizing as it nears the Sun. Once those materials are depleted some astronomers expect Comet ATLAS's brightness curve to flatten out, a common occurrence in comets that have rarely or never come close to the Sun before. Long-period comets that approach within 1 a.u. of our star have been known to split apart, disintegrate, and disappear. Comet ISON (C/2012 S1) offers a classic example. Shortly before its November 2013 perihelion, the comet crumbled into a cloud of dust and ice, dashing hopes for the spectacle so many of us had anticipated.

Comet ATLAS finder chart
The chart shows the position of Comet ATLAS (C/2019 Y4) through April 24th at 0h UT for the dates shown. Click the image for a zoom and here for a black-and-white PDF of the chart. As the comet approaches perihelion, we'll be providing updated charts.
Sky & Telescope

According to NASA’s JPL Horizons the comet could reach magnitude –5, exceeding Venus in brightness at perihelion on May 31st. Because it will lie 13° southwest of the Sun at that time, it might be possible to see the object in broad daylight with a properly shielded telescope.

That prediction may be overly optimistic however. In a March 19th notice from the Central Bureau for Astronomical Telegrams (CBAT), Director Daniel Green applied a formula based on the behavior of previous long-period, Sun-hugging comets and derived a more conservative peak magnitude of –0.3.

It's good news either way. In both predictions Comet ATLAS will reach naked-eye brightness in mid-May before it's lost in the solar glare. The JPL Horizons formula predicts a peak magnitude between 1 and 2, while Green anticipates that number to be between 2 and 3. During the first half of May the comet will appear low in the evening sky at dusk and early nightfall as it tracks through Perseus. Binoculars should reveal a bright, strongly condensed coma followed by dust and gas tails pointing away from the Sun. With a little luck we might even see the tail without optical aid.

After rounding the Sun, Comet ATLAS returns to view around June 15th at dawn in Orion for Southern Hemisphere skywatchers. Initially glowing at magnitude 3 or 4, the comet will fade quickly — assuming it survives a sizzling perihelic encounter!

How to See Comet ATLAS

Comet ATLAS (C/2019 Y4) sketch
On March 21.2 UT I observed Comet ATLAS in 10×50 binoculars . The sketch conveys its faint, diffuse appearance at the time. I estimated the comet's magnitude at 8.5 with a coma diameter of 12′ and DC (degree of condensation) of 2.
Bob King

For now, observers in the Northern Hemisphere can follow the comet from Ursa Major through Camelopardalis with a 6-inch or larger telescope. While visible in binoculars the comet is still quite diffuse and takes some effort to see. That should change soon.

In a telescope, Comet ATLAS shows a large, diffuse coma with a small, more compact knot at the center dotted with a faint, starlike nucleus. If you have a Swan band filter, which enhances carbon emissions from gas-rich comets, you'll find that Comet ATLAS responds well. I noted a distinct increase in the comet's contrast and visibility through the filter this month.

And what would comet-watching be without a picturesque "deep-sky drive-by" or two? Watch for Comet ATLAS to buzz within a degree of the galaxy NGC 2366 on April 3rd and pass directly in front of the pretty open cluster NGC 1545 in Perseus on May 14th.

Comet ATLAS (C/2019 Y4) trajectory
Comet ATLAS's trajectory is shown here starting several years before discovery (nested loops, left), and during the current apparition with markers every seven days, going several years into the future (nested loops, right).
Tom Ruen

The comet remains a circumpolar object for much of the U.S. and Europe until about two weeks before perihelion, when best viewing will be during the early evening hours. If the comet is especially dusty, we'll likely see a more spectacular tail instead of a bright, spiked fuzz ball. Be hopeful, but as always when it comes to these fragile objects, temper your expectations.

As Comet ATLAS approaches perihelion, I'll update with new maps and information. I'd love to hear what you're seeing and encourage you to share your observations and thoughts in the comments section. We all need some good news right now given the havoc wrought by the coronavirus. Comets have traditionally been viewed as bearers of malevolence throughout much of human history. In a twist of irony this latest emissary from the remote depths of the solar system may offer a needed dose of wonder.

Comments


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Tom-Reiland

March 26, 2020 at 4:47 am

I got my second observation of Comet Atlas 2019/Y4 in both the 21" Newtonian and the 5" Refractor last night at Wagman Observatory. The coma was more concentrated towards the center with a star-like nucleus. Later, I was able to spot it through my 10 X 50 binocs, just barely. I made a second binocular observation 90 minutes later to confirm my first one. My rough estimate of the magnitude is between 8.5 to 8.0 magnitude. My observation on March 1 put it at 11.5 to 12.0 magnitude and it was a much smaller, diffuse, round patch. The sky contrast was not exceptional, but it was better than the previous week. I would love to see it turn into a great morning comet similar to Comet West in 1976. The was the first spectacular comet that I observed. Later, I was able to view 3 of the 4 pieces of the nucleus after it broke up.

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Bob King

March 27, 2020 at 2:16 pm

Hi Tom,
I concur with your binocular estimate. I got 8.3 last night (March 26-27) in my 10x50s. West was my second spectacular comet. First was Bennett in 1969. Spring seems to be a happy time historically for bright comets for northern hemisphere observers. Just coincidentally of course.

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Tom-Reiland

March 30, 2020 at 3:59 am

I did not want to go to Wagman Obs tonight because of the late Moonset and the wind. I decided to set up my 5" f/5 Jaegar's Refractor in my backyard to see if I could locate Comet ATLAS c/2019 Y4. I went outside after 2:30 AM and started to hunt it in Camelopardalis near the border with Ursa Major and not far from M81 and M82.
I used 20mm and 18mm eyepieces (31X & 35X). I located it about 2:45 AM, but it was not easy to see because of the LP in Shaler. What a difference 11 driving miles make. It's still around 8 to 8.5 magnitude. There was no way that I could see the comet through my 10 X 50 binocs, though I tried.

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Bob King

March 30, 2020 at 10:10 am

Hi Tom,
Thanks for posting your observation. Like Doug's (below) it's good news for small telescope owners.

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Tom-Reiland

April 2, 2020 at 2:59 pm

I was able to see Comet ATLAS again in the 5" Refractor as well as the 21" Reflector last night, just after 4 AM this morning. I estimate it at 8 mag +/- , but the conditions were not as good as six nights ago, making it difficult to estimate its brightness. The sky was a little brighter (light pollution) and not as dark as the last time I was at Wagman Observatory. The magnification I used was 25X on the 5" and 127X on the 21". It might be another 10 nights to two weeks before I'll try again, because of interference
from the Moon and pending on the weather.

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cyrtonyx

April 3, 2020 at 4:12 pm

I remember Bennett. I was 8 years old. Saw it just before dawn due east right around Easter, as I recall. Although my memory is fuzzy, I do remember it had a nice long tail.

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Bob King

April 4, 2020 at 10:18 am

Crytonyx,

Comets are like old memories — a little fuzzy 🙂

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FifthWheelFollies

March 27, 2020 at 4:45 pm

I saw Bennett. Luckily, I had an early morning newspaper route at the time. I looked up and there it was. Very big and looking like it was going somewhere. Ranks up there with total solar eclipses on my must see list.

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Bob King

March 29, 2020 at 8:33 pm

Totally agree, Fifthwheel. Gorgeous spring sight!

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smarti

March 30, 2020 at 12:51 pm

West must have been a sight from what I hear.

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Bob King

March 30, 2020 at 1:31 pm

Smarti,

Indeed it was. I remember seeing the tail rise long before the head. It looked like smoke coming out of a chimney.

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OwlEye

March 30, 2020 at 11:03 pm

Bob,

Bennett was my first comet as well, seen in early April of 1970 from Woodland Hills, CA, and was spellbinding to a 13-year-old! West, nearly six years later, was the BEST - particularly due to the way I first saw it. I set my alarm every night starting just after the 1st of March that year, only to be thwarted by overcast each morning. Finally, I rose before the beginning of astronomical twilight on the 7th and it was clear, but by the time I reached my observing and shooting site eight miles SW of Delphos, Ohio, it had completely clouded over! However, as quickly as the clouds had come from the west, they rolled to the east, and I was treated to a singularly mind-blowing unveiling of the broad, curving dust and narrow ion tails! I about yelled myself hoarse, and could still see the inner tail and brilliant head at sunrise. The next morning was clear again, and this time I remembered to get some images.

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mark seibold

March 31, 2020 at 6:08 am

Thanks for posting the great article Bob. It's so encouraging to see others remembrances of past bright comets.
Although I vaguely remember my first comet sighting, as either Comet Arrend-Roland or Mrkos, in 1957, as I was a little over 3 years of age then, when my father pointed it out in the evening sky.
I'm not sure why I missed Comet Ikeya-Seki in 1965, as it was reported as a spectacular Kreutz-sungrazer.
Finally our Father awoke as early before school in my sophomore year of highschool in March of 1970, as he told us to walk outside and look East. It is still today the most spectacular thing I've ever observed in the sky in my life, to see the bright Bennett Comet hanging there at 4:30 a.m. not only with a bright tell but an obvious spiked front of the nucleus anti-tail, and in completely dark skies at an altitude of about 40 degrees. We lived seven miles east of our downtown city of Portland Oregon, in that era, so our city skies were relatively dark if you lived in the suburbs. The comet shone like a bright neon sign for several mornings. I'm not sure why I didn't at least try to use my parents Kodak box camera and strap it to the top of my 60mm Tasco refractor telescope to take a hand guided exposure. I had already tested myself in doing this by taking a 5 minute exposure of the Great Orion Nebula by manually guiding through the eyepiece, on one of Orion's Belt Stars, with the same crude box camera a few years before, when I bought the scope at age 13 and a half.
I was envious when one of my friends in high school brought a photo in the Comet Bennett to class. He used his father's 35mm antique camera, and exposed, I believe, high-speed Kodak Tri-X black and white film, a little past the limit for the focal length of the lens, possibly over 30 or 40 seconds on a tripod, as the stars trailed a slight bit in the picture, as did the comets nucleus. I wish I could locate him today and ask if he still has that photograph, and to post it somewhere.

Finally in 1976 I took my 1972 college days 35mm camera with me while on a driving route as a data courier driver. I had it loaded with Kodak high-speed ektachrome transparency film and I was prepared to photograph Comet West early that morning. I took several successful photos at varied exposure rates. Since that comment I have observed several more including the disappointments such as Comet Kohoutek.
after the brilliant display of Comets Bennett and West, I was disappointed in 1985~1986 by Halley's Comet, and didn't even bother trying to photograph it.
But since then I've photographed several others quite successfully in 1996, Comet Hyakutake, and then in '97 Comet Hale-Bopp. Since then with the acquisition of my first digital camera, only a Sony pocket camera in hand, I successfully captured Comet McNaught in January 2005 on the Southwest horizon in an orange twilight sunset sky from a hilltop near the home I designed and built in Troutdale Oregon for my wife and daughter and I.
Then there was a long pause again of un-photographible comets, until Comet Lovejoy in the winter of 2014 to 2015. Although I had a Celestron NextStar 5i Cassegrain since Celestron gave it to me to teach astronomy overseas in the Fiji islands in 2004, I've never used it for Equatorially well tracked astrophotography, and wondered why. So the next opportunity, a few comets that became within reach of longer time exposures, utilizing the telescopes equatorial tracking, was easy. I have an 8 photo compilation of several bright comets put together, which spans over 40 years starting with common West an ending with some unusual comets in the past few years, that I display often in my Facebook, but I thought there'd be an option to add a photo here in the comments. I'm not sure if I can see that option, but you can easily access my Facebook albums on the comets.

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Bob King

March 31, 2020 at 3:51 pm

Hi Mark,
I thoroughly enjoyed reading your account of the bright comets you've seen. We've shared many of the same. Like you I missed Ikeya-Seki in 1965 when it was at its best. I remember getting up one morning and looking out the window for it but it was cloudy. Much later I managed to see it in my telescope. Did you happen to catch Comet Bradfield in spring 2004 at dawn? It was also a beautiful but more subtle naked-eye comet.

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Zubenelgenubi 61

April 6, 2020 at 9:33 am

Although not in the great comet class due to perihelion taking place on the far side of the Sun, Halley in 1986 was visible for a long time, ranged over much of the sky, and presenting many different aspects. Based on overall impression, I would rank it third or fourth of the fifty-we comets I have seen. I was too young for Ikeya-Seki and Bennett, too inexperienced to pick up Kohoutek, and only saw West through my window a couple of times.

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Bob King

April 6, 2020 at 7:48 pm

Zuben,
I like Halley the same reasons — its constantly changing morphology.

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Rich5555

April 1, 2020 at 3:55 pm

Doesn't really seem to have brightened appreciably in 9 days since the first magnitude estimate I saw.

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Rod

March 26, 2020 at 9:49 am

In Maryland, I may get a view next Monday night when the skies are mostly clear. I plan to view using my 10-inch telescope and perhaps, near 0600 EDT on Tuesday morning, see Mars and Saturn close conjunction in Capricornus too 🙂

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Bob King

March 27, 2020 at 2:16 pm

Good luck and clear skies, Rod!

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John Rombi

March 27, 2020 at 5:21 pm

It's a shame that we won't see it in the SH....Many comments are made about "other" bright comets. Not much is said about Comet McNaught 2007. This was a daytime object.

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Bob King

March 28, 2020 at 8:51 pm

Hi John,
It was even beautiful here in the NH before it came to you. Fantastic comet equal to Hale-Bopp for southern hemisphere observers.

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Zubenelgenubi 61

March 26, 2020 at 6:43 pm

I really hope this is not confirmed to be the case, but the date of brightening appears to have slowed down in the last week or so. The supposed surge may have been due to the comet becoming bright enough for observers to include the outer parts of the coma in their estimates. Now that this has been factored in, the brightness curve is flattening out.

Since the comet is already eighth magnitude, it is likely to attain marginal naked eye visibility- perhaps a fuzzy spot like Wirtanen. I would be happy if the comet could attain even the CBAT level of brightness. It could be an interesting sight to the right of Venus in the mid-May western skies, but I don't expect greatness. I hope I am wrong, though.

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Bob King

March 27, 2020 at 2:19 pm

Hi Doug,
I am trying to keep that attitude too about this comet, the reason I choose not to overplay bright expectations in the article. Already however ATLAS is brighter than C/2017 T2. Last night I used the Swan filter again and the contrast gain and coma expansion were considerable.

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Joe Stieber

March 29, 2020 at 12:58 am

I finally got my first view on Friday evening, 27-March-2020. I picked it up with 15x56 binoculars at 8:55 pm EDT in the New Jersey Pines. That was five minutes after the end of astronomical twilight when there was still a 12% illuminated moon low in the west. Transparency was good, but not great, between passing cirrus clouds.

As I usually try to do, I found it without a looking at a finder chart. I just remembered from that afternoon when I was preparing charts that it would be about a binocular field left of the compact triangle formed by Rho, Sigma¹ and Sigma² UMa. Indeed, that's where I spotted a vague patch of haze, which I then confirmed as C/2019 Y4 with my charts.

I can see where those who don't follow comets too closely and are now looking at Y4 because of all the press about it might be a little disappointed. Fingers crossed that its appearance will change dramatically for the better in May, but in the meantime, I'm keeping my expectations in check.

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Bob King

March 29, 2020 at 12:10 pm

Hi Joe,
Thanks for sharing your report. For regular comet watchers ATLAS is coming along nicely, but for a typical skywatcher with compromised skies and a small telescope it's still a "faint, fuzzy patch". I was heartened to see how much more compact its core has become in recent days. I also spotted the tail spike projected across the coma.

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Dave Mitsky

March 29, 2020 at 2:00 pm

I brought my 15x70s with me to the orange-zone Naylor Observatory on the night of March 15th hoping to see Comet C/2019 Y4 (ATLAS) but the sky was just not dark enough. However, I was able to locate the comet with the observatory's 17" f/15 classical Cassegrain at 170x but it wasn't more than a faint fuzzball. I also viewed the comet at 116x and 216x, with the latter providing the best view. I was unable to detect it with the 5" f/5 finder scope

https://www.heavens-above.com/comet.aspx?cid=C%2F2019%20Y4&lat=40.1469&lng=-76.8989&loc=Edward+L.+Naylor+Astronomical+Center+%26+Observatory&alt=170.0&tz=EST

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Bob King

March 29, 2020 at 5:59 pm

Dave,
Sounds like bad light pollution but it's a good check on expectations because so many observers live under similar skies. Thank you!

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OwlEye

March 29, 2020 at 11:26 pm

Hi Bob,

I finally got some reasonably clear sky this evening, and even with some light cirrus and the moon over 5.5 days old, comet ATLAS had gotten a bit brighter than my first observation on the evening of March 20th. I, too, noticed the inner coma had gotten more compact and at times, using fixed averted vision, I believe I caught a fleeting twinkle of the nearly-stellar false nucleus. Again, as on the 20th of March, my best view was at 76 X in the 6-inch reflector. The coma was ~ 6' in diameter (not bad in the moonlight and thin cirrus!).

Regards,
Doug Z

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Bob King

March 30, 2020 at 10:09 am

Hi (real) Doug,
You saw a lot in a 6-inch given the increasing moonlight. Your observation will be heartening to owners of small telescopes. I'm going to look at the comet after moonset tomorrow morning and then check out the nice conjunction of Mars and Saturn.

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OwlEye

March 30, 2020 at 11:11 am

Weather permitting, I plan to follow the comet every evening as the moonlight increases, to see how long it remains visible in a 6-inch at 76 X. Should be challenging! DZ

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Bob King

March 30, 2020 at 1:30 pm

Doug,
Yes, it will but hopefully the comet will compensate by continuing to brighten.

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OwlEye

March 30, 2020 at 10:23 pm

Bob,
I was thinking the same thing - may it prove to be so!!

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Tom Hoffelder

April 14, 2020 at 10:04 am

Yes, Y1! Forecast is clear for tomorrow evening, but that is long range for Maine!

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Zubenelgenubi 61

March 30, 2020 at 1:15 pm

I would like to see a larger area finder chart accompanying the close up one that is published.

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Bob King

March 30, 2020 at 1:27 pm

Zuben,
A good idea! The reason the chart was kept to a month was to avoid clutter due to the comet's relatively faint (~8.5) magnitude at the time. The next chart will include the remainder of its pre-perihelion path — I promise!

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Rod

March 30, 2020 at 12:59 pm

Looks like folks are seeing the comet 🙂 Last night I got my first view near 2100 EDT using 10x50 binoculars. It was small, faint fuzzy near (21') HIP40215 star, mv+5.31. Today I updated Stellarium 0.20.0, updated Atlas C/2019 Y4 comet ephemeris. Starry Night is current. I will try and view again tonight using my telescopes near 2100 EDT. It is in a good position to see from my backyard sidewalk. Last night, clouds rolled in and covered up the waxing crescent Moon and the comet. This has been the viewing story at my location for a while. Today is clear, sunny and perhaps, a better evening. This morning I tried to view Mars getting closer to Saturn, however ground fog and overcast skies greeted me 🙂

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Bob King

March 30, 2020 at 1:29 pm

Rod,
Loved your report. A classic tete-a-tete with the elements. I've been there many times. Your persistence will pay off.

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Rod

March 30, 2020 at 11:33 pm

Bob King, *persistence will pay off* Yes! It was a great outdoors evening from 2000-2200 EDT tonight at my location in Maryland (stayed at home). The waxing crescent Moon, Venus below the Pleiades, Orion, Auriga, Leo and the comet. I viewed using my 10-inch telescope. Distinct fuzzy coma but not a bright comet. At 86x the core was brighter. Most of my viewing was at lower power 34/35x with wide field, about 1.8-degrees across, plenty of stars visible in the FOV too. Clear, cool skies with temp near 10C. I was bathed in moonlight while observing from my east pasture, ethereal experience. The waxing crescent Moon with earthshine was lovely. Early in the evening I placed the 10-inch telescope on Venus, punched me right in the eye I used the 2-inch eyepiece, I do not have planetary filters for the 2-inch piece. Three polar orbiting satellites passed by, one across the eyepiece view of the comet in Camelopardalis. Another passed through Auriga, about as bright as Capella. A good 2 hours plus, time well spent vs. watching the news --Rod

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Tom Hoffelder

April 5, 2020 at 10:30 pm

Hello Bob, another excellent article! And one with so much promise in one of my favorite realms of observing! I have logged 149 comets (I should say comet apparitions, since I include periodic comet returns on my spreadsheet), 19Y4 being the most recent. I have seen around 20 naked eye comets, but these are the ones that I remember as “gracing” the sky visually, in order of appearance: Mrkos, Kohoutek, West, Halley, Hyakutake and Hale-Bopp. As it happened, I didn’t remember the first one until somewhere between West and Halley, when I suddenly had a clear vision of my maternal grandfather showing me a comet while standing just outside the back door and looking to the west over his farm house with the big windmill beside us to the south. I had no idea exactly what year it was, but I knew it had to be when I was in grade school, so I checked to see what naked eye comets appeared 1953 to 59, and per Mark Seibold above, there were two in 1957 when I was 10 years old. I also remembered that it was a very warm evening and since this was in northern Indiana, it had to be summer. That and the direction we were looking tells me I saw Mrkos. Ever since remembering that, I’ve “blamed” my grandfather for my observing obsession. The good news with Atlas in May is that the moon won’t be a problem and it will be in the evening sky. The not so good news, for me in Maine anyway, is that it will be rather low: 11 degrees high at the end of nautical twilight and only 6.5 degrees at the end of astronomical twilight on the 18th, and losing 2 deg/day after that. Hopefully even then it will be bright enough that I can finally add another to my list of memorable naked eye comets. We will know soon!

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Zubenelgenubi 61

April 6, 2020 at 9:25 am

Most reports have Comet ATLAS stuck at 8th magnitude for the last couple of weeks, a bad sign. However, there has been moonlight, and some have been viewing the comet with too large an aperture. Starting on Thursday night, there will be a window of darker skies before the Moon rises. We will get a more meaningful clue then.

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OwlEye

April 6, 2020 at 3:33 pm

Hi Zube (and Bob),

I had mentioned above to Bob that I planned to observe the comet every clear evening as the moon waxed, just to see how long it would remain visible in a 6-inch scope until (or if) it was overwhelmed by the brightening moonlight. The last clear night was the 29th, and I reported that information above. Not until last night (4/5) did I have a clear evening to check in on it. My best magnification for ATLAS Y4 has been 76 X, and it was completely undetectable, not even the inner coma showed. I even tried other magnifications ranging from 30.5 X to 94 X - no joy. All my observations began after the end of astronomical twilight. I think the reports of it not getting any brighter (or possibly even fading a bit?) may be correct, because it seems that I should have possibly been able to see the inner coma (at least). Cannot wait for that window starting on Thursday!

Regards,
Doug Z

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Bob King

April 6, 2020 at 7:50 pm

Hi Doug,
As you already know the comet's nucleus appears to be in the process of breaking up over the past few nights. Not only has it plateaued but it appears to be fading too. Darn!! If the disintegration is significant it will be exciting to watch the comet's appearance change quickly in the next week. The moon couldn't depart sooner!

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Happylimpet

April 7, 2020 at 6:44 am

I got some good high res images last night showing some fragments. The main two are consistet with whats been reported in the Astronomical telegrams - a third trailing one seems new. Sorry for the facebook link.

https://www.facebook.com/photo.php?fbid=10156777189920689&set=pcb.1112736765563451&type=3&theater&ifg=1

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Bob King

April 7, 2020 at 11:34 am

Fantastic image, Nick! Please check your e-mail.

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Tom Hoffelder

April 8, 2020 at 8:56 am

Another one bites the dust (pun intended); sad sad sad. You did say they are unpredictable, and I said they are as difficult to predict as it is to forecast Maine weather. Now I'm thinking Maine weather is slightly easier and less depressing.

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Bob King

April 8, 2020 at 12:48 pm

Hi Tom,
Don't bury this one just yet! We'll see what happens. I saw the comet last night (April 8.14 UT) in my 15-inch. The full moon cast a lot of light but I could make out a ~5 arc-minute coma dimly at 64x. Definitely a fainter and less condensed nuclear region but overall around magnitude 9.5. I dug into the pseudo nucleus with 357x but couldn't hold any detail steady. Will have to wait for darker skies.

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OwlEye

April 8, 2020 at 11:52 pm

Hi Bob,

Just got done putting the 12.5-inch away. Spent most of the day doing maintenance and cleaning on it, and late in the afternoon, following a record-breaking high temperature of 88 degrees F., the foretold cold front blasted through our area, dropping the temp 20 degrees in 2 hours. Much cleaner air behind it!

Spotted ATLAS Y4 just before the end of astronomical twilight at 79x. The best view was at 99x, revealing an ~ 3 arcminute coma, with similar condensation to what you reported. As the moon got higher and scattered more light, the comet became a bit harder to see.

It is forecast to be clear here tomorrow, so hopefully much higher magnification will be possible before moonrise.

Regards,
Doug Z

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Bob King

April 9, 2020 at 10:59 am

Thank you, Doug for your observation. I wasn't able to see it last night but excited for dark skies before moonrise tonight.

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Fabrice Morat

April 11, 2020 at 7:03 am

Hello Bob,

Like you, i've observed the comet a few days ago with full moon. At low power with the 600mm dobson, i've seen an elongated shape, not spherical like in marth and the comet band filter was this time absolutely ineffective. i didn't know then what happened on this comet and i thought : perhaps a possible fragmentation ! Now, i've the response in detail, thank you. Fabrice M.

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Mark-Spearman

April 11, 2020 at 5:55 pm

Hi Bob,

I was able to get some images last night despite high clouds. Using MaximDL and doing some rough aperture photometry, I estimated the magnitude of the elongated nucleus at around 12.6 so it is definitely dimming. 🙁

Mark S.

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Bob King

April 12, 2020 at 11:36 am

Thanks, Mark for your observation. I estimated an overall magnitude of about 9.4 two nights ago on April 8.1 UT. At the limit of visibility in my 10x50 binoculars. Comet PanSTARRS on the other hand was much easier and has a fine, broad tail about 9 arc minutes long.

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Bob King

April 12, 2020 at 11:38 am

Thank you, Fabrice! I'm puzzled though about the comet filter observation. I used the filter two nights ago on April 8.1 UT and found that it still boosted the comet's contrast and expanded the coma by about an arc minute.

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Tom Hoffelder

April 13, 2020 at 6:45 pm

Bob, OK, I'm standing by! Right now I'm just hoping for a 3 comet evening, with 2017 T2 and 2019 Y1 being in the same part of the sky. Not as good as the night of 11/3-4/13, when I saw five in one night (Brewington, Lovejoy, ISON, LINEAR and Encke), four of them in 40 minutes in my 8 inch f/6 Newtonian. That was here in Norway Maine, my second 5 comet night. The first was 1/9/99, near Tulsa OK; they were Giacobini-Zinner, two LINEARs, Harrington-Abell and Jager. I didn't note the scope, but since Harrington-Abell was 11.5 mag, it was probably the C14.

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Bob King

April 13, 2020 at 8:26 pm

Me too, Tom. Is your third comet Y1?

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Chris-Dalla Piazza

April 11, 2020 at 10:56 pm

Looks about the same brightness as many sub visual comets that I've seen come and go but with the novelty of an elongated shape. It seems to drop off in brightness opposite its direction of travel. I'm not sure if this is a result of the fragmentation but most comets I've seen of this brightness have been spherical in shape and symmetrical in brightness.

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Bob King

April 12, 2020 at 11:35 am

Hi Chris,
I think that's what makes it fascinating to see — the elongated nucleus. I examined it at 357x the other night could just begin to tease out brightness variations along the length of the fragmented nucleus. It has faded overall however.

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Zubenelgenubi 61

April 13, 2020 at 9:38 am

According to the very detailed images on Spaceweather.com this morning, there still seems to be a small primary nucleus left, along with four or five fading fragments. Time will tell if this remnant can survive or itself will fragment, leaving nothing. If it did survive, is there enough left to amount to anything much?

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Bob King

April 13, 2020 at 11:40 am

Hi Zuben,
At least the comet's still with us. If we're lucky the fragments will be small and ATLAS will stick around for a while. I eagerly await every clear night in anticipation of new developments. That's why we like these fuzzy things so much.

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rcwelsh62

April 13, 2020 at 6:50 pm

I got this stack of 67 last night, and then dropped this moving of the apparent motion over 45 minutes. I was just super excited to get this far!

https://www.facebook.com/photo.php?fbid=10223083433296669&set=a.1130345741273&type=3&theater&notif_t=feedback_reaction_generic&notif_id=1586807970191336

https://www.youtube.com/watch?v=0heBtm5matw

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rcwelsh62

April 13, 2020 at 6:51 pm

movie*

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Bob King

April 14, 2020 at 3:22 pm

Congratulations, RC! Thank you for sharing your work with us.

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Mike T

April 13, 2020 at 8:33 pm

Last evening (April 12, 10-10:30pm MDT) was my best view of Y4 to date.  I had exceptionally clear and dark skies sans moon obviously. It was quite turbulent, however.  A cold-hard wind out of the north abbreviated my viewing session.  I might not have been fully dark-adapted before I retreated to a warm space.

I used 10x70 Fujinon binoculars, tripod mounted.  The overall presentation was, as one would expect, diffuse, but it was clearly "concentric" in brightness and undoubtedly elongated.  I thought that I could discern an extension (i.e. tail) "down and leftward"; but that would be sun-ward, not away.  Maybe that was real (i.e. our Earth-perspective) or maybe it was my "averted imagination."  Either way, it reminded me a lot of Bode's Galaxy, though larger and brighter.  Near it's core, it was m 8.5... conservatively.

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Bob King

April 13, 2020 at 8:58 pm

Mike,
Wow! You make me wish I didn't sell my 10x70 Fujinons. Great observation! I suspect like you do that what you saw was not the tail. The bright end of the coma faces west, and the comet is extended to the east.

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gtsviper

April 16, 2020 at 12:06 pm

Would I be able to capture Atlas the end of next week (no cloud cover then) with a DSLR and long expsoure in a dark site? I had lots of success capturing Wirtanen (sp?) on Dec 2018.

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Bob King

April 17, 2020 at 3:27 pm

gtsviper,
That depends on which ATLAS. Y4 is more extended and fainter, but with a modest telephoto, ISO 1600 and a couple minutes you should be able to capture it. Y1 is considerably brighter at them moment (small surge recently to mag. 7.4) and should look distinctly green. While small it will be obvious. You'll have no problem exposing for it.

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jimi-lowrey

April 16, 2020 at 3:18 pm

Last night I had a fantastic view of Y4 with my 48” reflector here at my home near Fort Davis Texas. I swept up the comet at 375X and was surprised at how well it showed. It had an elongated coma and fan shaped tail. I bumped up the power to 610X and at the very end of the coma a stellar knot was popping in and out with the seeing. I then went to 813X and I could see a second knot popping in and out. That is all the power the conditions would stand. This was my first view of this comet and i will keep at it I hope to see the different components as they are breaking up.

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Bob King

April 17, 2020 at 3:23 pm

Wow, Jimi! The perfect instrument for this comet. I'm jealous. Thanks for sharing what you saw.

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LeeH

April 29, 2020 at 11:46 pm

Tonight I saw a string of what looked like stars moving quickly across the sky. They were on the bright side of the moon, evenly spaced, and moving at the same speed. They appeared to come out of the darkness at the same spot and disappeared into the darkness at the same spot. There was a steady stream already in motion when I first saw it. I watched at least 30 pass by in less than a minute before it stopped. What did I see?

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Bob King

April 30, 2020 at 12:16 am

Hi Lee,
You saw the Starlink satellites. There are now 420 in orbit and they are approximately evenly spaced and follow one after the other. They were launched by SpaceX and will be used to provide worldwide Internet access. 12,000 are planned for orbit!

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