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w-Phobos_Shadow_-_1.jpgPhobos' penumbral shadow83 visitenessun commentoMareKromium
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z-Phobos-20130301_gusev2_f840.jpgPhobos' shadow over Gusev Crater83 visitenessun commentoMareKromium
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w-Phobos_shadow-233-150206-2345-4-nd-01-PhobosShadow.JPGPhobos' shadow80 visitenessun commentoMareKromium
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w-Phobos_Shadow_-_2.JPGPhobos' shadow...again!80 visitenessun commentoMareKromium
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w-Phobos_shadow-7507188_Mariner_9.jpgWhat a shadow!78 visitenessun commentoMareKromium
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x-Viking_Orbiter_1_Phobos_shadow_p101a_(1).jpgPhobos' shadow from Viking Orbiter 178 visiteTutte ombre "molto" simili (ellissoidi), eppure tutte molto diverse. Certo, le variabili in gioco sono tante, a cominciare dalla qualità intrinseca dei frame, però...MareKromium
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PSP_007769_9010-Stickney-1.jpgStickney Crater (Natural Colors + MULTISPECTRUM; credits: NASA & Lunexit)61 visitenessun commentoMareKromium
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PHOBOS-Image024-417-20081008-5889-6-src-03-PhobosSeries_H1.jpgThe Surface of Phobos: the "Striations"61 visiteThis image of Phobos’s surface was obtained by the Super Resolution Channel (or SRC, a part of the High Resolution Stereo Camera experiment) on board ESA’s Mars Express on 3 August 2008 (orbit 5889).
The distance from the moon’s centre was approx. 656 Km, and the image resolution is 6 mt/pixel. The original image has been corrected for mirror distortion.MareKromium
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Phobos-PIA01336.jpgHigh-Resolution MOC Image of Phobos' Face60 visiteThis image of Phobos, the inner and larger of the two moons of Mars, was taken by the Mars Global Surveyor on August 19, 1998. The minimum distance between the Spacecraft and Phobos was 1080 Km (about 671 miles).
Phobos was observed by both the Mars Orbiter Camera (MOC) and Thermal Emission Spectrometer (TES). This image is one of the highest resolution images (4 meters or 13 feet per picture element or pixel) ever obtained of the Martian satellite.
The image shows several new features of this lumpy moon -- features that are associated with the prominent crater seen in the upper left quarter of the image. This is the largest crater on Phobos, Stickney, 10 Km (about 6 miles) in diameter. Individual boulders are visible on the near rim of the crater (D), and are presumed to be ejecta blocks from the impact that formed Stickney. Some of these boulders are enormous - more than 50 meters (160 feet) across.
Also crossing at and near the rim of Stickney are shallow, elongated depressions called grooves. This crater is nearly half the size of Phobos and these grooves may be fractures caused by its formation. The far wall of the crater shows lighter and darker streaks going down the slopes (C). The presence of material of different brightness on the far crater slopes and in some of the grooves shows that the satellite is heterogeneous (that is, it is made of a mixture of different types of materials). The motion of debris down slopes is guided by gravity, which is only about 1/1000th that of the Earth -- e.g., a 68-Kg (150- pound) person would weigh only about 57 gr (2 ounces) on Phobos.
Previous images from the Viking Spacecraft in the 1970's were not of sufficient resolution to show the effectiveness of gravity on Phobos in moving material down slopes.MareKromium
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PHOBOS-Image002-415-20081008-5861-6-src-01-PhobosSeries_H1.jpgPhobos: close-up, from Mars Express58 visiteThis striking close-up image of Phobos was obtained by the Super Resolution Channel (or SRC, a part of the High Resolution Stereo Camera experiment) on board ESA’s Mars Express on 26 July 2008 (orbit 5861). The distance from the moon’s centre was 2295 Km, and the image resolution is 20 mt/pixel.
The Super Resolution Channel (SRC), is an additional camera sharing HRSC’s processing electronics. Unlike HRSC, SRC is a framing camera, taking a complete image during a single exposure like a conventional pocket camera. Its 975 mm Maksutov-Cassegrain telescope gives it a pixel-resolution about four times higher than that of HRSC.
Early in the mission, the thermal conditions of the instrument in space caused a distortion in its precision optics. This resulted in a performance lower than expected, with some blur and ghosting visible in the raw images.
However, a significant part of the degradation has now been compensated for by analysing the effect of the distortion on test images (with point-like stars as target) and applying a corrective processing.MareKromium
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PHOBOS-Image000-409-20081008-5870-6-nd3-02-PhobosSeries_H1.jpgGeometry of the Phobos fly-by58 visitenessun commentoMareKromium
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