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Comet McNaught plunges toward the Sun


frogfish

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Comet McNaught (C/2006 P1) is plunging toward the Sun. It won't hit, but at closest approach on Jan. 13th it will be only 0.17 AU away--much closer than Mercury (0.38 AU). When the hot comet emerges later this month it could be brighter than a 1st-magnitude star. Or not. No one knows what will happen.

At sunrise this morning in Vallentuna, Sweden, P-M Heden was able to photograph the comet through a break in the clouds:

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Details: Canon Digital Rebel XT, f/5.6, iso 100, 2s exp

"I had a beautiful view," he says. "I saw the comet with my naked eyes just before the sun made the sky too bright."

"The tail was a beautiful sight in binoculars," adds Haakon Dahle of Fjellhamar, Norway, who took this picture, a 1 second exposure at 800 ASA. "I also saw the comet with the naked eye," he confirms.

Soon, the comet will be too close to the Sun to see--unless you're SOHO. From Jan. 11th to 15th, the Solar and Heliospheric Observatory will monitor the comet-Sun encounter using its onboard coronagraph. A date of note is Jan. 14th when Comet McNaught passes less than a degree from the planet Mercury. Join SOHO for a ringside seat.

http://www.spaceweather.com

----------------

It's been raining here...Hopefully i'll be able to catch it before it dissappears, or after it reappeares later this month...

Edited by frogfish
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For some reason i always assumed comets contained a lot of ice, so i would have also assumed that ice to melt when passing very close to the sun...

Perhaps the comet will be smaller when it re-appears? :)

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Comet are essentially a dirty snowball. But they are so massive that changes in size would be very small...almost not apparent to scientists. Comets do lose A LOT of material because of the sun. Tons ans tons of debris.

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A Bright Comet Is Coming

Comet McNaught from Hammerfest, Norway Jan. 6, 2007. If you watch the morning or evening sky these days and have a clear view of the horizon, you will be able to spot a bright object with a prominent tail.

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Image above: Comet McNaught from Hammerfest, Norway

Jan. 6, 2007.

Credit: Roger Johansen.

Instructions for viewing the comet in the morning from Spaceweather.com:

1. At dawn, go outside and face east

2. Using binoculars, scan the horizon

3. The comet is located just south of due east

Instructions for viewing the comet in the evening from Spaceweather.com:

1. At sunset, go outside and face west

2. Using binoculars, scan the horizon

3. The comet is located low and to the right of Venus

4. A clear view of the horizon is essential

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Click image to enlarge.

That object is comet C/2006 P1 (Comet McNaught). It was discovered on August 7th, 2006 by the hugely successful comet discoverer Rob McNaught. At time of discovery, the comet was a very faint object, but the predicted perihelion distance (closest distance to the sun) of just 0.17 astronomical units (the average distance between the Earth and sun, about 150 million kilometers) indicated that the object has the potential to become very bright indeed. Nobody really knows just what this comet will look like at its closest point to the sun and that is where SOHO comes in! The LASCO instrument aboard SOHO has the ability to watch comets as they get extremely close to the sun. Fortunately for us, C/2006 P1 is going to pass right through the LASCO C3 field of view in less than a weeks' time! As soon as SOHO's cameras capture the comet, we will post images and further information to the SOHO website. In the meantime, you may enjoy looking at some photographs and checking out the links below for further information.

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Image above: The image shows the expected track of

the comet through SOHO's coronagraph LASCO C3.

Credit: NASA/ESA

The image above shows the expected track of the comet through SOHO's coronagraph LASCO C3. The comet will appear in the field of view of C3 at around 10:00 UT (05:00 EDT) on January 12th (a few hours before perihelion) in the upper-left of the images and travel almost vertically down, exiting C3's field of view in the lower left at roughly 03:00 UT on January 16th.

Recent estimates of the comet's maximal brightness have ranged widely from magnitude +2.1 (about as bright as Polaris, the North Star) to a super-bright -8.8 (about 40 times brighter than Venus)! The lower the magnitude number, the brighter the object. The brightest stars in the sky are categorized as zero or first magnitude. Negative magnitudes are reserved for the most brilliant objects: the brightest star is Sirius (-1.4); the full Moon is -12.7; the Sun is -26.7.

Current estimates put comet McNaught at magnitude 0 to -1, and it is still brightening. It could be -2 or -3 by the time it reaches LASCO's field of view. This means it will be brighter than comet NEAT or comet 96P/Machholz. In other words, this could be the brightest and most spectacular comet that SOHO has ever seen!

Related Links:

+ McNaught gallery on Spaceweather.com

Steele Hill

Goddard Space Flight Center

Bernard Fleck

ESA

Source: NASA - Exploring the Universe - Our Solar System

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SOHO prepares for comet McNaught


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The image shows the expected track of comet McNaught through SOHO's coronagraph LASCO C3. The comet will appear in the field of view of C3 at around 11:00 CET (10:00 UT) on 12 January 2007 (a few hours before perihelion) in the upper-left of the images and travel almost vertically down, exiting C3's field of view in the lower left at roughly 03:00UT on January 16th.

Recent estimates of the comet's maximal brightness have ranged widely from magnitude +2.1 (about as bright as Polaris, the North Star) to a super-bright -8.8 (about 40 times brighter than Venus)! The lower the magnitude number, the brighter the object. The brightest stars in the sky are categorized as zero or first magnitude. Negative magnitudes are reserved for the most brilliant objects: the brightest star is Sirius (-1.4); the full Moon is -12.7; the Sun is -26.7.

Current estimates put comet McNaught at magnitude 0 to -1, and it is still brightening. It could be -2 or -3 by the time it reaches LASCO's field of view. This means it will be brighter than comet NEAT or comet 96P/Machholz. In other words, this could be the brightest and most spectacular comet that SOHO has ever seen!

Credits: ESA, NASA SOHO/LASCO team


11 January 2007
Recently, sky watchers in the Northern Hemisphere have been enjoying the sight of Comet McNaught in the twilight sky. Now, solar physicists using the ESA-NASA SOHO spacecraft are getting ready for their view. For four days in January, the comet will pass through SOHO's line of sight and could be the brightest comet SOHO has ever seen.

As Comet McNaught heads towards its closest approach to the Sun on 12 January 2007, it will disappear from view for earthbound observers, becoming lost in the Sun's glare. That's where SOHO comes in. Poised in space between the Earth and Sun, SOHO ceaselessly watches the Sun and objects that pass nearby.

Comet McNaught will pass within a fifth of the distance between the Earth and the Sun. As the comet approaches the Sun, the amount of dust and gas it releases will increase dramatically, causing the comet to become extremely bright. "This might become the brightest comet SOHO has ever seen," says Bernhard Fleck, SOHO Project Scientist.


The material ejected from the comet forms the tails. There are two tails, the dust tail and the gas – or ion – tail. The dust tail is the brighter and is formed by the intense sunlight forcing dust particles away from the comet. The solar wind, a constant stream of material flowing from the Sun, drags ionized gas from the comet to create the ion-tail.

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Comet McNaught is plunging toward the Sun and brightening dramatically. The image was taken by Roger Johansen, Hammerfest, Norway, on 6 January 2007.

Credits: Roger Johansen


Researchers Karl Battams and Jeff Morrill at the Naval Research Laboratory in Washington, DC are planning colour filter observations of these two comet tails. "Close to the Sun the ion and dust tails move apart, a phenomenon that is often difficult to observe from the Earth. By measuring the ion-tail angle we can get information about the solar wind speed very close to the Sun," says Morrill.

Comet McNaught is moving through space on an inclined orbit. This will carry it above the Sun’s north pole and across the Sun’s equator, a place where there is a reversal of the magnetic properties of the solar wind. Crossing this boundary could cause the comet’s ion-tail to fragment. Observations of such events are generally very rare, so SOHO's images of comet McNaught constitute an exciting opportunity for scientists.

After SOHO's work is finished, the comet will emerge from the Sun’s glare and become visible again to earthbound sky watchers in the Southern Hemisphere. "It could become a really bright object in the twilight sky," says Fleck. The ghostly veils of a bright comet are amongst the most spectacular of sights that can be seen in the night sky.

Between 12 and 15 January, Comet McNaught will not be visible from Earth but everyone can still track the comet's passage near the Sun by looking at the SOHO images at http://soho.esac.esa.int/hotshots/.


Source: ESA - News
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Why doesnt this suprise me and why do us humans alawys in general take it for granted nothing will happen? Do we realy know ? what if ? it could happen? what could happen ? me talking to myself .?

It s happened before.

Oh.... see anything can change in an instant and always catch us off guard,lol

Lets hope this is just another bad Mc Donaldland story,.. Naught. wheww, im outta here.

Actually great find my as always, thanks frogfish and waspie, always good stuff

Abecrombie :tu:

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I've been trying to get a shot of this thing! its been so overcast here! if i get one, i'll post it!

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Why doesnt this suprise me and why do us humans alawys in general take it for granted nothing will happen?

Why doesn't what surprise you and because we understand the Laws Of Planetary Motion maybe? (In that order).

Do we realy know ?

We have a good idea.

what if ?

What if what?

it could happen?

What could happen?

what could happen ?

That's exactly what I said.

me talking to myself .?

Well that could be a bit of a problem I admit.

It s happened before.

Talking to yourself?

Oh.... see anything can change in an instant and always catch us off guard,lol

Not really. 'cos we understand the Laws Of Planetary Motion.

Lets hope this is just another bad Mc Donaldland story,.. Naught. wheww, im outta here.

You've lost me here. Something to do with a Big Mac and fries maybe?

Actually great find my as always, thanks frogfish and waspie, always good stuff

Abecrombie :tu:

It is, as always, a pleasure.

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Comet McNaught - A First Light Present for STEREO

01.12.07

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Click image to enlarge

This image of Comet McNaught comes from the Heliospheric Imager on one of the STEREO spacecraft, taken Jan. 11, 2007. To the right is the comet nucleus, so bright it saturates the detector creating a bright vertical band in the image. The comet's dynamic tails extend up and to the left.

The lowest of the tails is the ion tail, which points along the direction of the solar wind. Above that is the comet's dust tail pushed out by radiation pressure from the sun. The tail is highly structured, probably the result of dynamic activity in the comet itself.

Although the two STEREO observatories have been turning on their instruments since mid-December, the Heliospheric Imagers on this spacecraft turned on for the first time on Jan. 11 - just in time to see the spectacular Comet McNaught.

The Heliospheric Imagers are designed to observe the space between the Sun and the Earth in order to watch solar storms as they head our way. But here the Heliospheric Imagers are also able to observe Comet McNaught as it heads towards the sun.

STEREO's SECCHI/HI instrument was built by a consortium led by the Naval Research Laboratory (USA), and includes the University of Birmingham (UK), Rutherford Appleton Laboratory (UK) and Centre Spatiale de Liege (Belgium). Image credit: NASA

Related Links:

+ STEREO

+ First Light web feature

+ Comet McNaught

Rani Gran

Goddard Space Flight Center

Source: NASA - STEREO - News

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Been watching this every night for the last few days, sadly just went behind cloud tonight :(

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Been watching this every night for the last few days, sadly just went behind cloud tonight :(

Probably hiding from China.

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The Great Cometary Show


The European Southern Observatory (ESO) press release 05-07 is reproduced below:

ESO 05/07 - Science Release

19 January 2007
For Immediate Release

The Great Cometary Show

Comet McNaught Over Parana


Comet McNaught, the Great Comet of 2007, is no more visible for observers in the Northern Hemisphere. It does put an impressive show in the South, however, and observers in Chile, in particular at the Paranal Observatory, were able to capture amazing images, including a display reminiscent of an aurora!

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Comet McNaught and ATs

The Comet McNaught observed in the evening of 16 January 2007 from Paranal. Two of the four VLTI Auxiliary Telescopes are seen in the foreground.


Comet C/2006 P1 was discovered in August 2006 by Robert McNaught on images taken by D. M. Burton with the 0.5-m Uppsala Schmidt telescope in the course of the Siding Spring Survey (Australia). It is one of 29 comets discovered by this telescope since early 2004 in a project to systematically search the southern skies for asteroids, or comets, that can pass close to the Earth. At that time, the comet was only a very faint, barely diffuse object, about 50 000 times fainter than what the unaided eye can see.

However, as the comet came closer to the Sun, it brightened rapidly, in such a way as to become easily visible with the unaided eye in early January 2007, becoming brighter than Comet Hale-Bopp and Comet West, thereby earning its title of Great Comet of 2007. It even became the brightest comet in more than 40 years.

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'Old Tails'

The extended tail of Comet McNaught, seen from Paranal, observed in the evening of 18 January 2007, when the comet was setting behind the Pacific Ocean. The planet Venus is visible in the lower right of the image.



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The Comet and the Telescopes

The extended tail of Comet McNaught, seen from Paranal, observed in the evening of 18 January 2007, when the comet was setting behind the Pacific Ocean. In the foreground: one of the VLT Unit Telescope and two Auxiliary Telescopes.


Comet McNaught had its closest approach to the Sun on 12 January, being well inside the orbit of Mercury, with a minimum distance of only 17% the mean Earth-Sun distance. On January 13, it reached its maximum brightness when it was possibly brighter than Venus.

In early January, it was visible in the northern hemisphere but after passing the Sun, it only became visible from the southern hemisphere, entering the constellation Microscopium (The Microscope) on 18 January.

Astronomers in ESO's observatories in Chile are thus optimally placed to enjoy the show and certainly do not want to miss it. The comet displays a vivid coma and a lovely, sweeping tail.

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Comet McNaught

The Comet McNaught observed in the evening of 16 January 2007 from Paranal. The comet's image gets bent through the atmosphere and cloud layers.



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A Cometary 'Aurora'

The 'old tails' from Comet McNaught observed in the evening of 17 January 2007 from Paranal, when the comet had just set. The outcome resembles an aurora.


As the night deepens, and the comet had set, it revealed a sweeping fan that gives onlookers the impression they are witnessing an aurora, albeit the phenomenon is completely different. The structure in the tail is probably the fingerprint of past bursts of activity of the comet, releasing small dust particles whose paths are deflected by the solar light.

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Comet McNaught

The 'old tails' from Comet McNaught observed in the evening of 17 January 2007 from Paranal, when the comet had just set. The outcome resembles an aurora. In the foreground: one of the VLT Unit Telescope and three Auxiliary Telescopes



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Comet McNaught

The Comet McNaught observed in the evening of 17 January 2007 from Paranal.


The comet is now heading further south and should still be nicely visible for southern observers for several days.

More images of the comet are available at the McNaught ESO page.

Source: ESO Press Release pr-05-07
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  • 1 month later...
The Celestial Whirligig


The European Southern Observatory (ESO) press release 07-07 is reproduced below:

ESO 07/07 - Instrument Release

23 February 2007
For Immediate Release

The Celestial Whirligig

Unique Observations of Comet McNaught Reveal Sprinkling Nucleus


Comet McNaught, the Great Comet of 2007, has been delighting those who have seen it with the unaided eye as a spectacular display in the evening sky. Pushing ESO's New Technology Telescope to its limits, a team of European astronomers have obtained the first, and possibly unique, detailed observations of this object. Their images show spectacular jets of gas from the comet spiralling several thousands of kilometres into space, while the spectra reveal the presence of sodium in its atmosphere, something seen very rarely.

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Imaging of the central coma of Comet McNaught. Left: a raw image taken through a filter centred on the emission by CN gas.
Middle: the CN image processed using the Larson-Sekanina algorithm to reveal spiral jets of gas from the nucleus.
Right: A similarly processed image of the dust in the inner coma, showing a sunward plume and the dust being swept back into the tail. The
tail direction is roughly downwards in these images, which are orientated with North up and have a field of view of 2.4 arcmin on a side.


Comet C/2006 P1 (McNaught) has rightly earned the title of a 'Great Comet' - one so bright in the sky that such an occurrence could be expected just once in a generation (see ESO 05/07).

The problem for astronomers was that the comet stayed very close to the Sun and so was only visible very low on the horizon, making it impossible for most professional telescopes to study it in detail. One telescope, however, was up to the challenge: ESO's New Technology Telescope (NTT), at La Silla.

"We had previously pointed the NTT very low to observe the planet Mercury, which is very close to the Sun and is therefore only visible low in the sky just after sunset. I realised that we could take advantage of the same low pointing limit to observe the comet while it was near the Sun", said ESO astronomer Colin Snodgrass [1].

From the 29th January onwards, the comet was thus observed with the NTT, revealing in detail the heart of the comet. This was no easy feat as even with the NTT it was only observable for half an hour after sunset. Luckily, the NTT has another major advantage: it is equipped with the versatile ESO Multi Mode Instrument (EMMI), which can provide both imaging and spectroscopic observations across the visible wavelength range. This meant that the maximum amount of scientific data could be taken during the limited time available for observations.

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ESO's New Technology Telescope at La Silla is unique in that it can observe very low
on the horizon. The telescope is not housed in a traditional dome with a slot in the roof
to look at the sky, but in an innovative enclosure design with a sliding roof and wall that
open up to leave a view of the sky which goes all the way to the ground. The whole
building then rotates with the telescope to track objects on the sky. Inside the building
the telescope can swing up or down, and was built to be able to swing down far further
than normal telescopes: the NTT can point at objects only 10 degrees above the horizon


The unique images reveal three clear jets of gas, which are seen to spiral away from the nucleus as it rotates, like a Catherine Wheel firework.

"These jets are produced when sunlight heats ices on the surface of the comet, causing them to evaporate into space and create 'geyser' like jets of gas and small dust particles, which stretch over 13,000 km into space - greater than the diameter of the Earth - despite the fact that the nucleus of the comet is probably less than 25 km in diameter," explained Snodgrass.

By comparing images like this taken at different times, astronomers should be able to calculate how fast the nucleus rotates from the changing pattern of jets.

Other images also reveal that while the gas forms spiral jets, the large dust particles released from the comet follow a different pattern, as they are thrown off the comet's surface on the brightly lit side towards the Sun, producing a bright fan, which is then blown back by the pressure of sunlight itself.

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Long slit medium resolution spectrum taken on 3 February 2007 and covering the spectral range 450-650nm (the spectral direction is along
the horizontal axis, blue side to the left and red to the right). The spatial direction is along the vertical axis and covers about 80,000 km
on the sky. The nucleus has been centred in the 1" (800 km) slit, and is located at the position of the solar continuum in the spectrum.
The Sun direction is up and the tail direction is toward the bottom of the image. The many emission lines from the gaseous coma are
spatially extended by several thousands kilometres and grouped in so-called molecular bands. The sodium (NaI D) emission is visible as
the sharp and very extended line. In fact the sodium doublet (NaI D1 and D2 lines) is just resolved. On 3 February the flux that this line
had in the inner coma dropped by a factor of 10 in only a few days. For sake of clarity only some of the most conspicuous features are
annotated.


As well as taking images, the astronomers were able to investigate which gases were present in the comet's atmosphere [2] using spectroscopy. The usual gaseous species have been detected, such as cyanide, carbon, and ammonia, whose analysis will help the astronomers to determine the activity level of the comet and its chemical type.

But already in the first high resolution spectrum obtained on 29 January, the astronomers noted something quite unusual.

"We detected two very bright lines - the brightest of the whole spectrum taken on this day as a matter of fact - close to 589 nm and quickly identified them as belonging to neutral sodium atoms," said Emmanuël Jehin (ESO). "Further measurements showed this sodium emission to be extending over more than 100,000 km in the tail direction and fading rapidly with time."

Such lines have only been detected in the greatest comets of the past century like C/Ikeya-Seki in 1965, C/West in 1976 and C/Hale-Bopp in 1997, for which a very narrow sodium tail was even photographed. This straight neutral tail appears in addition to the dust and ionised gas tails when the comet is close to the Sun.

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Photograph of the comet tail from Paranal, after the comet
itself had set, with the laser guide star system above Yepun
(Unit Telescope 4) in the foreground. The laser is used to
produce a fake 'star' on the sky to allow the changing
atmosphere to be corrected. It works by making sodium
atoms high in the atmosphere glow - these atoms may
have originally come from comets like McNaught.
Photo by Emmanuel Jehin, ESO


"Its origin lies most probably in the dissociation of the cometary dust grains," said Jehin. "In very active comets, which are also usually the ones which pass closer to the Sun, the dust grains are vaporised under the intense heat and start releasing sodium atoms which then react to the solar radiation and emit light—at the very same yellow-orange wavelength of the lamps on our streets."

Sodium has also been observed around Mercury and the Moon forming a very tenuous atmosphere. But closer to us, at 90 km altitude in our atmosphere, there is the so-called 'sodium layer'. The origin of that layer is not well known but might be coming from the ablation of meteoroids that are burning (due to their high entry speed in the atmosphere) at the same altitude. As most shooting stars (or meteors) originate from comets (annual showers like the Eta Aquarids and Orionids originate from comet P/Halley, the Leonids come from comet P/Tempel-Tuttle, and the Perseids from comet P/Swift-Tuttle), the sodium in those dust particles might just be the same. As a kind of gift to the astronomers that layer is used by observatories like Paranal to produce with a laser an artificial star that allows for the correction of atmospheric turbulence!

Notes

[1] The team is composed of Colin Snodgrass, Emmanuël Jehin, and Olivier Hainaut (ESO), Alan Fitzsimmons (Queen's University, Belfast, UK), and Jean Manfroid and Damien Hutsemékers (Université de Liège, Belgium). These results were presented in a Circular Telegram to the International Astronomical Union (IAU CBET 832).

[2] When a comet is approaching the Sun, the ices trapped in the small nucleus sublimate, sometimes in the form of very strong gaseous jets, dragging in the process a lot of dust particles into space and forming a dusty atmosphere - called the coma - of several thousands of kilometers around the nucleus. All those molecules and dust particles are then pushed in the direction opposite to the Sun (by the solar radiation pressure), creating the gaseous and dust tails of the comet.

Source: ESO Press Release pr-07-07
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