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Comets-Comet_Hartley_2-EB-LXTT4.jpgComet "Hartley 2" (credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)67 visitenessun commentoMareKromium
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Comets-Comet_Hartley_2-EB-LXTT5.jpgComet "Hartley 2" (credits for the additional process. and color.: Elisabetta Bonora - Lunexit Team)58 visitenessun commentoMareKromium
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Comets-Comet_Hartley_2-MF-LXTT3.jpgComet "Hartley 2" (possible Natural Colors; credits for the additional process. and color.: Dr Marco Faccin - Lunexit Team)118 visitenessun commentoMareKromium
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Comets-Comet_Hartley_2-MF-LXTT4.jpgComet "Hartley 2" (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)169 visite...Come da richiesta del nostro Amico e Socio, "AndreaGG"...MareKromium
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Comets-Comet_Hartley_2-NASA-0.jpgComet "Hartley 2" (an Image-Mosaic by NASA, JPL-Caltech, UMD, EPOXI Mission)87 visiteDa "NASA - Picture of the Day" del giorno 5 Novembre 2010:"Follow these 5 frames clockwise starting from the top left to track the view from the EPOXI Mission Spacecraft as it approached, passed under, and then looked back at the nucleus of comet Hartley 2 on November 4.
Its closest approach distance was about 700 Km. In fact, this encounter was the 5th time a spacecraft from planet Earth has imaged a comet close-up. But Hartley 2's Nucleus is definitely the smallest one so far, its long axis spanning only about 2 Km (such as approx. 1,2 miles).
Though Hartley 2 is small, these stunning images showing Jets of Dust and Gas indicate an impressively active surface. The Jets are seen originating from the rough surface areas, with Sunlight illuminating the Nucleus from the right. Remarkably, rough areas at both ends of the elongated Nucleus are joined by a narrower, smooth waist.
The EPOXI mission reuses the Deep Impact Spacecraft that launched a probe impacting the Nucleus of comet Tempel 1 in 2005".MareKromium
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Comets-Comet_Hartley_2-NASA-1.jpgComet "Hartley 2" (Dimensions)93 visitenessun commentoMareKromium
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Comets-Comet_Hartley_2-NASA-2.jpgComet "Hartley 2" (Close-up and Dimensions)86 visitenessun commentoMareKromium
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Comets-Comet_Holmes-0.jpgA "Light Arrow" is heading towards "Heart & Soul"...64 visiteCaption NASA:"Two spectacular comets graced Earth's skies during 2007.
Both comets became bright enough to be seen by the unaided eye of the casual sky enthusiast. Early in 2007, Comet McNaught grew brighter than any comet in 40 years, displaying a beautiful dust tail that flowed across the sky.
Comet McNaught (a.k.a. c/2006 P1) became known as the "Great Comet" of 2007, sported unusual striations in its expansive dust tail, and showed unexpectedly complex chemistry in its ion tail.
Toward the year's end, normally docile and faint Comet Holmes brightened suddenly and unexpectedly to naked eye visibility. Remarkably, Comet 17P/Holmes stayed bright for weeks even though it lies beyond the orbit of Mars.
No distant comet in recent history has remained so bright for so long.
In this view, a white Comet Holmes was photographed in early December posing with the Heart and Soul Nebulae".MareKromium
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Comets-Comet_Holmes-TView.jpgTelescopic View of the Comet Holmes56 visiteCaption NASA, da "NASA - Picture of the Day" del 29 Ottobre 2007:"What's happened to Comet Holmes? A normally docile comet discovered over 100 years ago, Comet 17P/Holmes suddenly became nearly one million times brighter last week, possibly over just a few hours. In astronomical terms, the comet brightened from magnitude 17, only visible through a good telescope, to magnitude 3, becoming visible with the unaided eye. Comet Holmes had already passed its closest to the Sun in 2007 May outside the orbit of Mars and was heading back out near Jupiter's orbit when the outburst occurred. The comet's sudden brightening is likely due to some sort of sunlight-reflecting outgassing event, possibly related to ice melting over a gas-filled cavern, or possibly even a partial breakup of the comet's nucleus. Pictured above through a small telescope, Comet Holmes appeared as a fuzzy yellow spot, significantly larger in angular size than Earth-atmosphere blurred distant stars. Although Comet Holmes' orbit will place it in northern hemisphere skies for the next two years, whether it will best be viewed through a telescope or sunglasses remains unknown".MareKromium
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Comets-Comet_Holmes-TW-P17HolmesWeb3_goldman.jpgComet 17-P-Holmes and its Golden Coma55 visiteCaption NASA, da "NASA - Picture of the Day", del 3 Novembre 2007:"Surprising Comet Holmes remains easily visible as a round, fuzzy cloud in the Northern constellation Perseus. Skywatchers with telescopes, binoculars, or those that just decide to look up can enjoy the Solar System's latest prodigy as it glides about 150 MKM from Earth, beyond the orbit of Mars.
Still expanding, Holmes now appears to be about 1/3 the size of the Full Moon, and many observers report a yellowish tint to the dusty coma. A golden color does dominate this telescopic view recorded on November 1, showing variations across the coma's bright central region.
But where's the comet's tail? Like any good comet, Holmes' tail would tend to point away from the Sun. That direction is nearly along our line-of-sight behind the comet, making its tail very difficult to see". MareKromium
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Comets-Comet_Holmes-UV.gifComet 17-P-Holmes55 visiteCaption NASA, da "NASA - Picture of the Day" del 30 Ottobre 2007:"Go outside tonight and see Comet Holmes.
No binoculars or telescopes are needed -- just curiosity and a sky map.
Last week, Comet 17P/Holmes underwent an unusual outburst that vaulted it unexpectedly from obscurity into one of the brightest comets in recent years.
Sky enthusiasts from the Northern Hemisphere have been following the comet's progress closely. Pictured above Quebec, Canada, the coma of Comet Holmes has been noticeably expanding over the past few days. In the above picture, an image of Jupiter has been placed artificially nearby to allow for a comparison of angular sizes.
Jupiter has been scaled to the size it would appear at the current location of Comet Holmes. How Comet Holmes will further evolve is unknown, with one possibility being that the expanding gas cloud that started from its recent outburst will slowly disperse and fade".MareKromium
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Comets-Comet_Holmes-UW.jpgComet 17-P-Holmes is getting Bigger!60 visiteCaption NASA, da "NASA - Picture of the Day", del 5 Novembre 2007:"Comet Holmes continues to be an impressive sight to the unaided eye. The comet has diminished in brightness only slightly, and now clearly appears to have a larger angular extent than stars and planets.
Astrophotographers have also noted a distinctly green appearance to the comet's coma over the past week.
Pictured above over Spain in 3 digitally combined exposures, Comet 17P/Holmes now clearly sports a tail. The blue ion tail is created by the solar wind impacting ions in the coma of Comet Holmes and pushing them away from the Sun. Comet Holmes underwent an unexpected and dramatic increase in brightness starting only two weeks ago. The detail visible in Comet Holmes' tail indicates that the explosion of dust and gas that created this dramatic brightness increase is in an ongoing and complex event.
Comet Holmes will move only slightly on the sky over the next month (such as December 2007)".MareKromium
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