We warned you it was going to happen, and here’s visual proof! In this comet encounter of the extragalactic kind, Comet PanSTARRS and the Andromeda Galaxy met each other in the skies above Earth. This great image by Brendan Alexander in Ireland shows the spectacular view. He said it was “a difficult image to capture due to low cloud, the low altitude of the target and tracking issue. I hope to get the chance to improve on this!”
Here’s another image from UT reader Anna Morris:
Want to see this meetup for yourself? Tonight might be even better:
As Comet 2011 L4 PanSTARRS moves out of the inner solar system, we’ve got another comet coming into view this month for northern hemisphere observers.
Comet C/2012 F6 Lemmon is set to become a binocular object low to the southeast at dawn for low northern latitudes in the first week of April. And no, this isn’t an April Fools’ Day hoax, despite the comet’s name. Comet Lemmon (with two m’s) was discovered by the Mount Lemmon Sky Survey (MLSS) based outside of Tucson, Arizona on March 23, 2012. MLSS is part of the Catalina Sky Survey which searches for Near Earth Asteroids. We’ve got another comet coming into view this month for northern hemisphere observers as Comet 2011 L4 PanSTARRS moves out of the inner solar system.
The comet is on an extremely long elliptical orbit, with a period of over 11,000 years. Comet Lemmon just passed perihelion at 0.74 astronomical units from the Sun on March 24th.
Southern hemisphere observers have been getting some great views of Comet Lemmon since the beginning of this year. It passed only three degrees from the south celestial pole on February 5th, and since that time has been racing up the “0 Hour” line in right ascension. If that location sounds familiar, that’s because another notable comet, 2011 L4 PanSTARRS has been doing the same. In fact, astrophotographers in the southern hemisphere were able to catch both comets in the same field of view last month.
Another celestial body occupies 0 Hour neighborhood this time of year. The Sun just passed the vernal equinox marking the start of Spring in the northern hemisphere and Fall in the southern on March 19th.
And like PanSTARRS, Comet Lemmon has a very steep orbit inclined 82.6° relative to the ecliptic.
Comet Lemmon broke naked-eye visibility reaching +6th magnitude in late February and has thus far closely matched expectations. Current reports place it at magnitude +4 to +5 as it crosses northward through the constellation Cetus. Predictions place the maximum post-perihelion brightness between magnitudes +3 and +5 in early April, and thus far, Comet Lemmon seems to be performing right down the middle of this range.
Southern observers have caught a diffuse greenish 30” in diameter nucleus on time exposures accompanied by a short, spikey tail. Keep in mind, the quoted brightness of a comet is extended over its entire surface area. Thus, while a +4th magnitude star may be easily visible in the dawn, a 3rd or even 2nd magnitude comet may be invisible to the unaided eye. Anyone who attempted to spot Comet PanSTARRS in the dusk last month knows how notoriously fickle it actually was. Binoculars are your friend in this endeavor. Begin slowly sweeping the southeast horizon about an hour before local sunrise looking for a fuzzy “star” that refuses to reach focus. Comet Lemmon will get progressively easier in the dawn sky for latitudes successively farther north as the month of April progresses.
Comet Lemmon will continue to gain elevation as it crosses from Cetus into the constellation Pisces on April 13th. An interesting grouping occurs as the planet Mercury passes only a few degrees from the comet from April 15th to April 17th. Having just past greatest elongation on March 31st, Mercury will shine at magnitude -0.1 and make a good guide to locate the comet in brightening dawn skies. The pair is joined by the waning crescent Moon on the mornings of April 7th and 8th which may also provide for the first sighting opportunities from low north latitudes around these dates.
The Moon reaches New phase on Wednesday, April 10th at 5:35AM EDT/9:35 UT. It will be out of the morning sky for the next couple of weeks until it reaches Full on April 25th, at which point it will undergo the first eclipse of 2013, a very shallow partial. (More on that later this month!)
Comet Lemmon will then slide across the celestial equator on April 20th and cross the plane of the ecliptic on April 22nd as it heads up into the constellation Andromeda in mid-May. We’re expecting Comet Lemmon to be a fine binocular object for late April, but perhaps not as widely observed due to its morning position as PanSTARRS was in the dusk.
By mid-May, Comet Lemmon will have dipped back down below +6th magnitude and faded out of interest to all but a few deep sky enthusiasts. Comet Lemmon will pass within 10° of the north celestial pole on August 9th, headed back out into the icy depths of the solar system not to return for another 11,000-odd years.
It’s interesting to see how these two springtime comets will effect observers expectations for the passage of Comet C/2012 S1 ISON. Will this in fact be the touted “Comet of the Century?” Much hinges on whether ISON survives its November 28th perihelion only 1,166,000 kilometers from the center of our Sun (that’s 0.68 solar-radii or about 3 times the Earth-Moon distance from the surface of the Sun). If so, we could be in for a fine “Christmas Comet” rivaling the passage of Comet Lovejoy in late 2011. On the other hand, a disintegration of Comet ISON would be more akin to the fizzle of Comet Elenin earlier in 2011.
In the meantime, enjoy Comet Lemmon as an Act 2 in the 2013 Three Act “Year of the Comet!”
I’m completely envious of this view! Not only is there a stunning winter vista of mountains and a fjord near Tromso, Norway, but in the peaceful evening twilight, Comet PanSTARRS (C/2011 L4) shows up. To top off the view, a sudden burst of aurora borealis makes an appearance! This view was captured by Babak Tafreshi on March 20, 2013.
See some of his stunning images below:
Click on each of the images for a larger view at Tafreshi’s website.
Will the comet that’s been billed as the “the comet of the century” live up to expectations? Astronomers are getting a better idea of the makeup of Comet C/2012 S1 (ISON), and have now taken a look at it with the Swift satellite. They’ve been able to make initial estimates of the size of the comet’s nucleus.
“Comet ISON has the potential to be among the brightest comets of the last 50 years, which gives us a rare opportunity to observe its changes in great detail and over an extended period,” said Lead Investigator Dennis Bodewits, an astronomer at the University of Maryland College Park (UMCP.)
Bodewits and his team used Swift’s Ultraviolet/Optical Telescope (UVOT) to make initial estimates of the comet’s water and dust production, and then infer the size of its icy nucleus. They observed the comet on January 30 and then again late in February.
The January observations revealed that ISON was shedding about 112,000 pounds (51,000 kg) of dust, or about two-thirds the mass of an unfueled space shuttle, every minute. By contrast, the comet was producing only about 130 pounds (60 kg) of water every minute, or about four times the amount flowing out of a residential sprinkler system.
Similar levels of activity were observed in February, and the team plans additional UVOT observations.
Using the water and dust production, the astronomers estimated the size of ISON’s icy nucleus as roughly 3 miles (5 km) across, a typical size for a comet. This assumes that only the fraction of the surface most directly exposed to the Sun, about 10 percent of the total, is actively producing jets. The astronomers noted that these rates of water and dust production are relatively uncertain because of the comet’s faintness.
“The mismatch we detect between the amount of dust and water produced tells us that ISON’s water sublimation is not yet powering its jets because the comet is still too far from the Sun,” Bodewits said. “Other more volatile materials, such as carbon dioxide or carbon monoxide ice, evaporate at greater distances and are now fueling ISON’s activity.”
At the time, the comet was 375 million miles (604 million km) from Earth and 460 million miles (740 million km) from the Sun. ISON was at magnitude 15.7 on the astronomical brightness scale, or about 5,000 times fainter than the threshold of human vision.
Like all comets, ISON is a clump of frozen gases mixed with dust. Often described as “dirty snowballs,” comets emit gas and dust whenever they venture near enough to the Sun that the icy material transforms from a solid to gas, a process called sublimation. Jets powered by sublimating ice also release dust, which reflects sunlight and brightens the comet.
Typically, a comet’s water content remains frozen until it comes within about three times Earth’s distance to the Sun. While Swift’s UVOT cannot detect water directly, the molecule quickly breaks into hydrogen atoms and hydroxyl (OH) molecules when exposed to ultraviolet sunlight. The UVOT detects light emitted by hydroxyl and other important molecular fragments as well as sunlight reflected from dust.
The Deep Impact spacecraft also imaged Comet ISON in mid-January, and NASA and ESA are planning an observing campaign with the rovers and orbiters at Mars around October 1 when the inbound comet passes about 6.7 million miles (10.8 million km) from Mars.
“During this close encounter, comet ISON may be observable to NASA and ESA spacecraft now working at Mars,” said Michael Kelley, an astronomer at UMCP and also a Swift and CIOC team member. “Personally, I’m hoping we’ll see a dramatic postcard image taken by NASA’s latest Mars explorer, the Curiosity rover.”
Fifty-eight days later, on Nov. 28, ISON will make a sweltering passage around the Sun. The comet will approach within about 730,000 miles (1.2 million km) of its visible surface, which classifies ISON as a sungrazing comet. In late November, its icy material will furiously sublimate and release torrents of dust as the surface erodes under the sun’s fierce heat, all as sun-monitoring satellites look on. Around this time, the comet may become bright enough to glimpse just by holding up a hand to block the sun’s glare.
An important question is whether ISON will continue to brighten at the same pace once water evaporation becomes the dominant source for its jets. Will the comet sizzle or fizzle?
“It looks promising, but that’s all we can say for sure now,” said Matthew Knight, an astronomer at Lowell Observatory in Flagstaff, Arizona, and a member of the Swift and CIOC teams. “Past comets have failed to live up to expectations once they reached the inner solar system, and only observations over the next few months will improve our knowledge of how ISON will perform.”
Based on ISON’s orbit, astronomers think the comet is making its first-ever trip through the inner solar system. Before beginning its long fall toward the Sun, the comet resided in the Oort comet cloud, a vast shell of perhaps a trillion icy bodies that extends from the outer reaches of the planetary system to about a third of the distance to the star nearest the Sun.
Formally designated C/2012 S1 (ISON), the comet was discovered on Sept. 21, 2012, by Russian astronomers Vitali Nevski and Artyom Novichonok using a telescope of the International Scientific Optical Network located near Kislovodsk.
Sungrazing comets often shed large fragments or even completely disrupt following close encounters with the Sun, but for ISON neither fate is a forgone conclusion.
“We estimate that as much as 10 percent of the comet’s diameter may erode away, but this probably won’t devastate it,” explained Knight. Nearly all of the energy reaching the comet acts to sublimate its ice, an evaporative process that cools the comet’s surface and keeps it from reaching extreme temperatures despite its proximity to the sun.
Following ISON’s solar encounter, the comet will depart the sun and move toward Earth, appearing in evening twilight through December. It will swing past Earth on Dec. 26, approaching within 39.9 million miles (64.2 million km) or about 167 times farther than the Moon.
There is a small but non-negligible chance that Comet 2013 A1 will hit Mars October of 2014. According the latest calculations from JPL, the comet is estimated to come within 120,000 kilometers (74,000 miles). In this video, various NASA scientists discuss the potential impact, and invariably view such an impact as scientifically very intriguing.
“I think of it as a giant climate experiment,” said Michael Meyer, lead scientist for the Mars Exploration Program. “An impact would loft a lot of stuff into the Martian atmosphere–dust, sand, water and other debris. The result could be a warmer, wetter Mars than we’re accustomed to today.”
An impact would likely have consequences for the current rovers on Mars. Meyer said the solar-powered Opportunity might have a hard time surviving if the atmosphere became opaque. Nuclear-powered Curiosity, though, would carry on just fine. He also notes that Mars orbiters might have trouble seeing the surface, for a while at least, until the debris begins to clear.
The trajectory for comet Siding Spring is being refined as more observations are made. Rob McNaught discovered this comet on Jan. 3, 2013, at Siding Spring Observatory in Australia, and looking back at archival observations has unearthed more images of the comet, extending the observation interval back to Oct. 4, 2012. Further refinement to its orbit is expected as more observational data is obtained.
Scientists estimate the nucleus of the comet is about 1 to 3 km in diameter. If it gets close to Mars and is grabbed by its gravity,and IF there was an impact it would be a substantial hit. “If it does hit Mars, it would deliver as much energy as 35 million megatons of TNT,” said Don Yeomans of NASA’s Near-Earth Object Program at JPL. According to what Yeomans says in this video, the current odds of it hitting Mars is about 1 in 2,000, but according to the parameters at JPL’s website, it appears the odds are about 1 in 10,000.
Get ready for an comet encounter of the extragalactic kind. In less than a week, Comet PANSTARRS will slide by the Andromeda Galaxy, the brightest galaxy visible in northern hemisphere skies. On and around that date, you’ll be able to see them both glowing softly together in late evening and early morning twilight.
Their apparent proximity if of course pure sleight of hand; the comet will be a mere 121 million miles (195 million km) from Earth on that date compared to Andromeda’s 2.5 billion light years. For what it’s worth, 121 million miles (195 million km) equates to 0.00002 light years. Let’s just say they’re WAY far apart in reality. Their juxtaposition will make for enjoyable binocular viewing as well as offer astrophotographers an opportunity to create a classic image.
Last night under the clearest of skies I easily found Comet C/2011 L4 PANSTARRS in the constellation Andromeda about 15 degrees above the horizon an hour after sunset. Twilight was still a factor as was the rising full moon. That’s probably why the comet remained at the very limit of naked eye vision. Binoculars – I use 10x50s – clearly showed the comet’s bright parabolic head and two degrees (four full diameters) of tail streaming up and to the right.
The comet has faded considerably since it first emerged into the evening twilight three weeks ago. Its head now shines around magnitude 3.5 and is noticeably fainter than the stars of the Big Dipper. As compensation, PANSTARRS is now easier to find, since it’s both higher up in the sky and near a string of moderately bright stars in the constellation Andromeda.
PANSTARRS treks northward through Andromeda en route to the W of Cassiopeia in the next two weeks. It won’t be long before the comet becomes circumpolar and remains visible all night long. The term refers to celestial objects that circle around the pole star without setting. The Big Dipper is the most familiar circumpolar constellation for much of the U.S. and Canada.
On its journey to all-night visibility, PANSTARRS started pulling a double-shift this week. You can now see it both at dusk and at dawn. Although a bright moon will compromise the dawn view for a few days, you can watch for the comet low in the northeastern sky starting about hour and 15 minutes before sunrise. For the moment, it’s about the same altitude above the horizon during both morning and evening hours. Evening is still preferred only because the bright moon has finally departed the sky during the hour or so the comet is visible.
Through my 15-inch telescope last night, PANSTARRS’ head held a brilliant topaz gem – the false nucleus. This tiny ball of bright, fuzzy light contains the icy comet itself, hidden behind a fury of its own dust and vapor boiled off by the sun’s heat.
Here’s some additional images and videos of PANSTARRS that Universe Today has received from readers:
Zlatan Merakov created this timelapse from images he took on March 20 from Smolyan, Bulgaria.
Wow – what an image! Michael Jaeger’s photo of Comet C/2011 L4 PANSTARRS on March 19 resembles those taken by the orbiting Stereo-B spacecraft. Check out this video (and the one below) to see what I mean. Most observers using binoculars and telescopes are seeing the comet’s head, bright false nucleus and a single plume-like tail.
Careful photography like Jaeger’s reveals so much more – two bright, broad dust tails and three shorter spikes. One of the dust tails peels off to the left of the comet’s head, the other extends upward feather-like before splitting into two separate streamers. There are also several narrow, spike-like tails due to various excited elements and gas emissions from the comet’s icy nucleus.
Video of Comet PANSTARRS made from pictures taken by NASA’s STEREO-B spacecraft on March 13, one of two spacecraft that orbit ahead and behind Earth monitoring solar activity on the sun’s farside.
Michael Jaeger of Austria has been shooting pictures of comets since 1982. His images always reveal details that entice visual observers to go out and look for more than what first meets the eye. Last night I got my first look at the comet through a telescope and was delighted at the sight of its smooth, luminous tail and brilliant yellow false-nucleus. The false nucleus is the bright spot visible in the center of the PANSTARRS’ head; in 10×50 binoculars it looks like a star. Through a telescope it’s a fuzzy, yellow pea. Buried deep within the false nucleus is the icy comet nucleus itself, vaporizing in the sun’s heat and shrouded by its own dust.
The comet has faded in the past week or two from 1st magnitude – equal to some of the brightest stars – to about magnitude 2.5 or somewhat fainter than the stars of the Big Dipper. In very clear skies, it was still dimly visible with the naked eye about 40 minutes after sunset low in the northwestern sky. I only knew where to look after first finding the comet in 10×50 binoculars. The tail points straight up and stretches nearly 2 degrees in length once the sky gets dark enough to increase contrast and before PANSTARRS sinks too low. I kept it in view for nearly an hour from a wind-whipped location north of Duluth, Minn.
Through the telescope the nucleus blazed yellow from sunlit dust. Set inside the comet’s sleek, smooth head it reminded me of a lighthouse beacon shining through the mist. Gorgeous! The tail trailed bent back to the northeast with a slight arc. I highly recommend setting up your telescope for a look at PANSTARRS, if for no other reason than to see the beauty of the false-nucleus within the finger-like tail.
You can use the chart to help you find the comet for the remainder of the month. It shows the comet’s position every 3 days now through March 31 from mid-northern latitudes, specially 42 degrees north (Chicago, Ill.). If you live in the northern U.S., the comet will be in approximately the same positions but slightly higher in the sky; in the southern U.S. it will be a little lower. Notice the “15 degree” altitude line. If you set the bottom of your fist flat on the horizon, the 15 degree line is a fist and a half above that level.
Time lapse video made by Patrick Cullis showing Comet PANSTARRS setting behind the Flatirons of Boulder, Col. on March 19. As you watch, notice how the comet appears against the sky background and the direction it moves toward the horizon – both clues to help you find it.
The map compensates for the sun rising later each night and shows the comet’s height above the horizon when the sun is 7.5 degrees below the horizon. 7.5 degrees corresponds to about 30 minutes after sunset. Notice that the sun moves northward (to the right) just like the comet does over the next couple weeks but more slowly.
See those yellow numbers along the map’s horizon? Those are compass bearings called azimuths. If you have a compass, dig it out and give it a look. Every compass is marked in degrees of azimuth. 270 degrees is due west, 285 degrees is a fist and a half to the right of due west, 315 degrees is exactly halfway between due west and due north. North can be either 360 degrees or 0 degrees. Azimuths are simple way to subdivide directions to make them more precise.
The next time it’s clear, bring your binoculars and a compass (if needed) and find a location with a great view of the western sky preferably down to the horizon. Use the map along with the compass bearings to guide your eyes in the right direction. You can also use the sun’s position below the horizon to point you to the comet by angling up from the lingering glow at the sunset point. Remember to first focus your binoculars on the moon, cloud bank or star before attempting to find PANSTARRS. There’s nothing more frustrating than sweeping for a fuzzy comet with an out-of-focus instrument.
Comet C/2011 L4 (PanSTARRS) keeps getting easier to see, and over the weekend, we were inundated with images and videos from astrophotographers around the world. NASA says that solar heating from the comet’s close pass of the Sun last week has caused the comet to glow brighter than a first magnitude star. Bright twilight sharply reduces visibility, but it is still an easy target for binoculars and small telescopes 1 and 2 hours after sunset. And as of March 15th, people reported they can see the comet with the unaided eye.
Photographer Fred Kamphues took this timelapse from the Leiden Observatory in The Netherlands, the oldest astronomical observatory in the world still active today. Kamphues notes that astronomer Jan Hendrik Oort of Leiden Observatory discovered the origin of comets in 1950. The observatory is used today by student astronomers to learn observing.
This image is from Chris Schur in Arizona. He says, “Note the fan tail appearing! Also the tail is really starting to curve in the images. Very easy to see naked eye, and so was the yellow color in binoculars when it gets lower.”
Comet Pan-STARRS thrills Dutch observers of the Night Sky on March 14, 2013 shortly after sunset- note the rich hues. Shot with a Canon 60D camera and Canon 100/400 mm lens, exposure time 2 seconds, ISO 800. Credit: Rob van Mackelenbergh See viewing guide and sky maps below Update – see readers photo below[/caption]
Comet Pan-STARRS (C/2011 L4) is exciting amateur astronomers observing the night sky worldwide as it becomes visible in the northern latitudes after sunset. And now it’s wowing crowds in Europe and all over Holland – north to south.
Check out the beautiful, richly hued new photos of Comet Pan-STARRS captured on March 14, 2013 by Dutch astrophotographer Rob van Mackelenbergh.
“I took these photos in the southern part of the Netherlands on Thursday evening, March 14, at around 7:45 pm Dutch time with my Canon 60 D camera.”
“I was observing from the grounds of our astronomy club – “Sterrenwacht Halley” – named in honor of Halley’s Comet.”
Comet Pan-STARRS is a non-periodic comet from the Oort Cloud that was discovered in June 2011 by the Pan-STARRS telescope located near the summit of the Hawaiian Island of Maui.
The comet just reached perihelion – closest approach to the Sun – on March 10, 2013. It passed closest to Earth on March 5 and has an orbital period of 106,000 years.
“Over 30 people were watching with me and they were all very excited, looking with binoculars and cameras. People were cheering. They were so excited to see the comet. But it was very cold, about minus 2 C,” said Mackelenbergh.
The “Sterrenwacht Halley” Observatory was built in 1987 and houses a Planetarium and a Celestron C14 Schmidt-Cassegrain telescope. It’s located about 50 km from the border with Belgium, near Den Bosch – the capitol city of southern Holland.
“It was hard to see the comet with the naked eye. But we were able to watch it for about 45 minutes altogether in the west, after the sun set.”
“The sky was completely clear except for a few scattered clouds near the horizon. After the comet set, we went inside the observatory for a general lecture about Comets and especially Comets Pan-STARRS and ISON because most of the people were not aware about this year’s pair of bright comets.”
“So everyone was lucky to see Comet Pan-STARRS because suddenly the sky cleared of thick clouds!”
“In the past I also saw Comet Halley and Comet Hale-Bopp, but these are my first ever comet photos and I’m really excited !”
“I hope to see Comet Pan-STARRS again in the coming days when the sky is clear,” Mackelenbergh told me.
Over the next 2 weeks or so the sunset comet may grow in brightness even as it recedes from Earth into darker skies. Right now it’s about magnitude 0.2.
So keep looking with your binoculars; look west for up to 1 to 2 hours after sunset – and keep your eyes peeled.
You want images and videos of Comet C/2011 L4 (PANSTARRS)? We’ve got ’em! We’ll start with this stunning view from Japan, taken by Jason Hill. But there’s lots more below:
This timelapse comes from Andrew Takano, a graduate student at the University of Texas at Austin:
Photographer Chris Schur said last night’s views were “the best and brightest comet yet in the western Arizona Sunset sky!” Schur said via email. “I was able to go much deeper tonight using an 80mm Zeiss refractor and Canon Xti. The head shows more fan like protrusions, and the tail is now really shaping up. … The comet here at our elevation of 5150 feet was very easy to see the entire time it was up, and I would rate it at first magnitude for sure.”
Comet Panstarrs above Boulder, Colorado on the evening of March 13, 2013, courtesy of Patrick Cullis:
You can see more at our Flickr page, and we’ll keep adding and posting! Thanks to everyone who has been so generous with sharing their great photos and videos.
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