Saturn: the "Ringed Beauty" and His Moons
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Daphnis-N00156646-48-EB-LXTT.jpgGravitational Pulls from Daphnis (an Image-Mosaic in Natural Colors by Elisabetta Bonora - Lunexit Team)55 visitenessun commentoMareKromium
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Daphnis-PIA07809-1.jpgDaphnis and Keeler (context image)55 visiteCaption NASA originale:"Daphnis, the tiny moon that inhabits the Keeler Gap in the outer edge of Saturn's A-Ring, is captured here in remarkable detail with its entourage of waves.
The edge waves are especially bright in places where Ring material piles up, a characteristic that has been seen in computer simulations of the interactions between gap-embedded moons and the surrounding ring particles.
The 7 Km-wide (about 4,3 mile) moon appears to have an unusual shape in this image. It is not simply a bright dot, but instead exhibits a dimmer component immediately to its left. Though it is far from certain, this component may be Ring material caught in the act of accreting onto Daphnis, a process currently being studied by imaging scientists.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 9, 2006, at a distance of approx. 422.000 Km (such as about 262.000 miles) from Saturn. Image scale is roughly 2 Km (a little more than 1 mile) per pixel".
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Daphnis-PIA07809-2.jpgDaphnis and Keeler (detail mgnf)112 visitenessun commento
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Daphnis-PIA08171.jpgDaphnis54 visiteThis splendid view offers a detailed look at the faint Rings within the Cassini Division as well as a rare glimpse of the "Keeler Gap Moon", Daphnis. The small, ring embedded moon is a bright unresolved speck above center, near the outer edge of the A ring.
Discovered in Cassini images in 2005, Daphnis is a mere 7 Km (a little less than 4 miles) across.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 20, 2006, at a distance of approx. 483.000 Km (such as about 300.000 miles) from Saturn. The image scale on the sky at the distance of Daphnis is about 2 Km (a little more than 1 mile) per pixel.
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Daphnis-PIA08924.jpgDaphnis is there...somewhere!55 visiteCaption NASA:"The presence of the tiny ring moon Daphnis is betrayed by the edge waves it creates in the Keeler Gap.
The Gap is a narrow lane, about 42 Km (26 miles) wide, in Saturn's outer A-Ring. Daphnis (7 Km, or 4,3 miles across) was discovered in Cassini spacecraft images at the same time that scientists spotted the edge waves. Researchers had suspected the presence of a moon in this gap after Pan was discovered in Voyager spacecraft images taken 25 years earlier.
This view looks toward the unilluminated side of the Rings from about 54° above the Ring-Plane.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 17, 2007 at a distance of approx.y 1,8 MKM (1,1 MMs) from Saturn.
Image scale is roughly 10 Km (about 6 miles) per pixel".MareKromium
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Daphnis-PIA09902.jpgDaphnis and a Little Star...57 visiteCaption NASA:"The Cassini Spacecraft captures a view showing two of Saturn's moons and their gravitational effects on nearby Rings.
At top, Daphnis (about 8 Km, or 5 miles across at its widest point) streaks through the Keeler Gap, with its ever-present edge waves. At center, Prometheus (about 86 Km, or 53 miles across at its widest point) pulls away from a recent encounter with the F-Rring. A bright background star is visible below the F-Ring.
This view looks toward the unilluminated side of the Rings from about 41° above the Ring-Plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 8, 2008. The view was acquired at a distance of approx. 1,3 MKM (such as about 788.000 miles) from Prometheus and at a Sun-Prometheus-Spacecraft, or phase, angle of 53°.
Image scale is roughly 8 Km (about 5 miles) per pixel".
Nota Lunexit: noi vediamo Daphnis, la "Piccola Stella" in basso rispetto all'Anello "F" e la scia lasciata da Prometheus (sull'estrema Sx del frame) a seguito del suo transito ma, di Prometheus...nessuna traccia! E Voi? Lo vedete Prometheus?MareKromium
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Daphnis-PIA11637.jpgHeavy Disturbances55 visiteCaption NASA:"This Cassini image, which at first appears to show a serene scene, in fact reveals dramatic disturbances created in Saturn's A-Ring by its moon Daphnis.
Near the center of the image, tiny Daphnis (about 8 Km across) appears as a bright dot in the Keeler Gap near the edge waves it has created in the A-Ring. The moon has an inclined orbit and its gravitational pull both perturbs the orbits of the particles of the A-Ring forming the Keeler Gap's edge and sculpts the edge into waves having both horizontal (radial) and out-of-plane components. Material on the inner edge of the gap orbits faster than the moon so that the waves there lead the moon in its orbit. Material on the outer edge moves slower than the moon, so waves there trail the moon.
Epimetheus (approx. 113 Km, or about 70 miles across) orbits beyond the F-Ring at the bottom of the image. Bright specks in the image are background stars.
This view looks toward the Northern, sunlit side of the Rings, from about 11° above the Ring-Plane.
The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on Sept. 24, 2009. The view was obtained at a distance of approx. 1,8 MKM (about 1,1 MMs) from Daphnis.
Image scale is roughly 11 Km (a little less than 7 miles) per pixel".MareKromium
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Daphnis_and_Rings-PIA11656-1.jpgWavy Shadows (ctx frame)55 visiteCaption NASA:"This image of shadows on the Rings and others like it (see also PIA11653 and PIA11655) are only possible around the time of Saturn's equinox which occurs every half-Saturn-year, equivalent to about 15 Earth years. The illumination geometry that accompanies equinox lowers the Sun's angle to the Ring-Plane and causes out-of-plane structures to cast long shadows across the Rings.
This view looks toward the unilluminated side of the Rings from about 49° above the Ring-Plane. The image was taken in visible light with the Cassini Spacecraft narrow-angle camera on April 13, 2009.
The view was obtained at a distance of approx. 1,2 MKM (about 746.000 miles) from Daphnis and at a Sun-Daphnis-Spacecraft, or phase, angle of 56°.
Image scale is roughly 7 Km (about 5 miles) per pixel".MareKromium
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Daphnis_and_Rings-PIA11656-2.JPGWavy Shadows (edm)55 visiteCaption NASA:"Never-before-seen tall vertical structures created by Saturn's moon Daphnis rise above the Planet's otherwise flat, thin disk of Rings to cast long shadows in this Cassini image.
Daphnis, approx. 8 Km (about 5 miles) across, occupies an inclined orbit within the about 42-Km (approx. 26-mile) wide Keeler Gap in Saturn's outer A-Ring. Recent analyses by imaging scientists published in the Astronomical Journal illustrate how the moon's gravitational pull perturbs the orbits of the particles forming the Gap's edge and sculpts the edge into waves having both vertical and horizontal components.
Measurements of the shadows in this and other images indicate that the vertical structures range between one-half to 1,5 Km tall (about 1/3rd to one mile), making them as much as 150 times as high as the Ring is thick. The main A, B and C-Rings are only about 10 meters (about 30 feet) thick. Daphnis itself can be seen casting a shadow onto the nearby Ring".MareKromium
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Dione & Rhea-PIA08261.jpgNight-lights, in the Saturnshine...55 visiteCaption NASA originale:"Soft light from Saturn lifts the veil of night from the moons Dione (lower left) and Rhea (upper right).
A scant crescent on each satellite marks the limit of the Sun's direct reach. The remaining light is reflected onto the moons by the Ringed Planet (Saturn-shine).
This view was acquired using an image compression scheme that results in minor artifacts being present - on Rhea in particular.
Rhea (approx. 1.528 Km, or 949 miles across - pictured above) is somewhat bland in appearance at this image scale, although Dione's spectacular fractures stand out marvelously. Dione is approx. 1.126 Km (about 700 miles) across.
North, on both moons, is rotated 45° to the right.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 11, 2006 at a distance of approx. 2,6 MKM (about 1,6 MMs) from Dione and 2.8 MKM (1,7 MMs) from Rhea. Image scale is about 15 Km (approx. 10 miles) per pixel on Dione and about 17 Km (approx. 11 miles) on Rhea".
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Dione from 6.200.000 Km.jpgDione from 6.200.000 Km55 visitenessun commento
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Dione from Voyager 1.jpgDione from Voyager 1107 visiteUna splendida immagine in "colori naturali" ma con i contrasti leggermente amplificati (amplificati---->enhanced), in maniera tale da favorire la visione dei piccoli dettagli della superficie.
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