| Risultati della ricerca nelle immagini - "images" |
Asteroids-1992-CO.jpgAsteroid 1992 CO57 visitenessun commento
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Asteroids-Annefrank_Asteroid-PIA02885_modest.jpgAsteroid Annefrank from Stardust64 visiteAsteroid Annefrank is seen as irregularly shaped, cratered body in an image taken by NASA's Stardust spacecraft during a Nov. 2 flyby of the asteroid.
Stardust flew within about 3.300 Km (about 2.050 miles) of the asteroid as a rehearsal for the spacecraft's encounter with its primary target, comet Wild 2, in January 2004. The camera's resolution was sufficient to show that Annefrank is about 8 Km (5 miles) in length, twice the predicted size from Earth-based observations. The surface reflects about 0,1 to 0,2% of sunlight, slightly less than anticipated. A few craters that are hundreds of meters across can be seen. The straight edge in the right side of the image may be an artifact of processing.
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Asteroids-Hygiea.jpgAsteroid 10 Hygiea78 visiteGrazie al lavoro della "Two Micron All Sky Survey - 2MASS" siamo in grado di offrirvi le immagini di qualche asteroide del tutto sconosciuto (crediamo) a coloro che non siano - in qualche modo - direttamente "addetti ai lavori" nei Campi dell'Astronomia e/o dell'Astrofisica (Studenti delle due Discipline inclusi).
Si tratta di immagini che non ci dicono molto, dal punto di vista di un eventuale studio delle caratteristiche superficiali di questi oggetti (a dire il vero una cosa sembrano dirla: si tratta di oggetti davvero molto luminosi!), ma che, in ogni caso, rimangono molto suggestive e sono capaci di mostrarci dei "frammenti" di Cielo che contengono, oltre ai cosiddetti "corpi fissi" (cioè stelle e galassie), anche degli oggetti "mutevoli e transitori" (almeno dal punto di vista di chi li osserva).
Gli Asteroidi, appunto.
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Asteroids-Pallas.jpgAsteroid 2 Pallas54 visitenessun commento
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Comets-Borrelly_Comet-PIA03500_modest.jpgThe "Borrelly" Comet from Deep Space 154 visiteIn this highest resolution view of the icy, rocky nucleus of comet Borrelly, (about 45 meters or 150 feet per pixel) a variety of terrains and surface textures, mountains and fault structures, and darkened material are visible over the nucleus's surface. This was the final image of the nucleus of comet Borrelly, taken just 160 seconds before Deep Space1's closest approach to it. This image shows the 8-km (5-mile) long nucleus about 3417 kilometers (over 2,000 miles) away.
Smooth, rolling plains containing brighter regions are present in the middle of the nucleus and seem to be the source of dust jets seen in the coma. The rugged land found at both ends of the nucleus has many high ridges along the jagged line between day and night on the comet. This rough terrain contains very dark patches that appear to be elevated compared to surrounding areas. In some places the dark material accentuates grooves and apparent faults.
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Comets-Comet_Ikeya_Zhang_2.jpgComet Ikeya-Zhang (from Colorado)60 visiteThis lovely early evening view of the comet in Rocky Mountain skies looks northwest over ridges and low clouds. The time exposure was recorded on March 31st from an 8.000 foot elevation near Yampa, Colorado, USA. Sporting a sweeping yellowish dust tail and blue ion tail eight to ten degrees long, Ikeya-Zhang is nestled near the horizon in the northern constellation of Andromeda. To the comet's left is the bright star Mirach or Beta Andromedae while the stretched celestial fuzzball to the comet's right is M 31 or the Andromeda galaxy, the nearest bright spiral galaxy to our own Milky Way. As the days pass, Comet Ikeya-Zhang's apparent motion through the sky is towards the right in this image. Tonight, comet-watchers blessed with clear skies should find Ikeya-Zhang posing perfectly for binoculars and cameras just above M 31, less than two degrees from the center of the bright galaxy.
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Comets-Comet_Ikeya_Zhang_3.jpgComet Ikeya-Zhang - the "ion tail"66 visiteThis composite color image from March 3rd, 2002, captured with a wide-field telescope, shows this active comet's bright, condensed coma and a delightful array of subtle structures in its developing tail. The bluish tail stretches for 5 degrees or so against a background of stars in the constellation Pisces. Cataloged as comet C/2002 C1, improved orbit determinations now make it seem very likely that Comet Ikeya-Zhang has been around here before. Refined calculations indicate this comet's last trip through the inner Solar System was 344 years ago, in 1661, when it was recorded as a bright comet.
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Comets-Comet_Ikeya_Zhang_4.jpgComet Ikeya-Zhang - the "ion tail"64 visiteAs Comet Ikeya-Zhang approached the Sun, it developed a complex blue "ion tail". The "ion tail" is composed of ions that boiled off the nucleus and were pushed away from the Sun by the out-flowing fast-moving particles of the solar wind. Complexity in the tail is created by comet nucleus rotation, variability in the comet surface evaporation rate and variability of the Sun's magnetic field and solar wind.
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Comets-Comet_Mach_Holz.jpgThe C/2004 Q2 Comet97 visiteScoperta solo pochi mesi fa, la Cometa C/2004 Q2 (Machholz) è già chiaramente visibile (a magn. 5 o superiore) nei Cieli del Sud. Ma nessuna paura, non occorrerà viaggiare per vederla: essa si sta rapidamente portando verso i nostri Cieli e, nel frattempo, continuerà ad aumentare il suo splendore (probabilmente sino alla prima metà di Gennaio 2005). La luminosità massima che C/2004 Q2 potrà raggiungere non ci è ancora nota; ciò che sappiamo, invece, è che essa resterà nei "nostri" Cieli per buona parte del 2005 e la potremo anche vedere in prossimità della Stella Polare nei primi giorni di Marzo. L'immagine che Vi proponiamo (da "NASA - Picture of the Day" del 13.12.2004) è stata ripresa ai primi di Dicembre e, come potete vedere, la cometa già ci mostra una consistente "chioma", un'abbondante coda di polveri e detriti (di colore bianco e verde) ed un'abbastanza intricata "coda ionica" (andante verso la Dx dell'Osservatore), che presenta delle increspature verso la fine.
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Comets-Comet_Machholz-Pleiades.jpgComet Machholz and M 4572 visiteRipresa amatoriale (ma di grande effetto scenico) effettuata il giorno 9 Gennaio 2005 dalla Germania - Baviera (località Oberjoch) dal Sig. Stefan Seip. Perfetta la visione della chioma - color verde/acqua - della Cometa (le dimensioni stimate della chioma stessa si aggirano intorno ai 500.000 Km mentre il suo nucleo roccioso dovrebbe avere un diametro compreso fra i 5/7 Km) e molto suggestiva la combinazione (ma si tratta, come ovvio, di un semplice effetto prospettico) fra l'alone blu proprio di M 45 e la coda ionica (anch'essa vagamente bluastra) della Cometa Machholz. Da notarsi che le dimensioni ridotte (ma solo in apparenza) della coda di Machholz (la quale si estende per svariati milioni di Km - 8/10) dipendono anch'esse da un semplice effetto prospettico il quale sfavorisce la nostra osservazione.
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Comets-Comet_Machholz.jpgComet Machholz67 visiteDa "NASA - Picture of the Day" del 5 Gennaio 2005:"Good views of Comet Machholz are in store for northern hemisphere comet watchers in January. Now making its closest approach to planet Earth, the comet will pass near the lovely Pleiades star cluster on January 7th and the double star cluster in Perseus on January 27th as Machholz moves relatively quickly through the evening sky. Currently just visible to the unaided eye from dark locations, the comet should be an easy target in binoculars or a small telescope. In fact, this telephoto time exposure from January 1, shows Comet Machholz sporting two lovely tails in skies over Colorado, USA. Extending to the left, strands of the comet's ion or gas tail are readily affected by the solar breeze and point away from the Sun. Dust, which tends to trail along the comet's orbit, forms the tail jutting down and to the right".
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Comets-Halley-30155.jpgThe Halley Comet, from Giotto53 visiteCaption ESA originale:"A composite image of the nucleus of comet Halley. This image is composed of 68 images of varying resolution. The data at the brightest point on the nucleus is at the highest resolution (50 m).
The Sun comes from 30° above the horizontal to the left and is 17° behind the image plane (observation phase angle of 107°). The night side of the nucleus can be seen silhouetted against a background of bright dust in the far-field. Jets can be seen originating from 2 regions on the nucleus. Structure can be seen within the jets. A bright area is seen within the night side of the nucleus. We believe this to be a hill or mountain approximately 500 mt high. Other surface details can be seen in the illuminated region".
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