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The Trojan Moons: Helene, from 760.000 Km
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Caption NASA originale:"Saturn's moons Helene and tiny Polydeuces (not seen here) are Trojan moons of Dione, orbiting about 60° ahead of and behind, the much larger moon. Trojan moons are usually found near gravitationally stable points ahead or behind a larger moon. Polydeuces (or S/2004 S5) was discovered by the Cassini imaging team. Helene is 32 Km (20 miles) across, while Dione is 1.118 Km (695 miles) across.
Tethys also has two of its own Trojan moons.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2005, at a distance of approx. 760.000 Km (such as about 472.000 miles) from Helene. The image scale is 5 Km (about 3 miles) per pixel. This view of Helene has been magnified by a factor of three and sharpened to aid visibility".
Nota: raffrontate questa immagine di Helene con quella ottenuta dalla Sonda Voyager 2. Ma secondo Voi stiamo guardando sempre lo stesso oggetto?!?
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(Dettagli)
