Cassini: Moon Specks

[bystander]

NASA | JPL-Caltech | Cassini Solstice Mission | CICLOPS | 2012 Apr 30

Moon Specks

A pair of Saturn's many moons joins the planet in this Cassini spacecraft scene.

Tethys (660 miles, or 1,062 kilometers across) appears as a small white dot above the rings on the far left of the image. Enceladus (313 miles, or 504 kilometers across) appears as a smaller bright speck beside the planet as seen from this vantage point. The rings cast wide shadows on the planet's southern latitudes.

This view looks toward the southern, unilluminated side of the rings from about 1 degree below the ringplane.

The image was taken in visible green light with the Cassini spacecraft wide-angle camera on Jan. 19, 2012. The view was obtained at a distance of approximately 1.8 million miles (2.9 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 63 degrees. Image scale is 104 miles (167 kilometers) per pixel on Saturn.

Credit: NASA/JPL-Caltech/Space Science Institute

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[owlice]

I love these; thank you for posting this, bystander!

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--------------           Tethy          Enceladus
------------------------------------------------------
Apparent magnitude        10.2           11.7 
Albedo  (bond)            0.80           0.99
Discovered by          G. D. Cassini   William Herschel
Discovery date         March 21, 1684  August 28, 1789
Adjective               Tethyan        Enceladean
Semi-major axis         295,000 km     238,000 km
Eccentricity             0.0001         0.0047
Orbital period           1.89 d         1.37 d
Inclination               1.12°          0.019°
Mean radius              531.1 km       252.1 km
Mass (in earth moons)    0.0084         0.00147
Specific density         0.984          1.609
Surface gravity          0.147 m/s²     0.114 m/s²
Escape velocity           394 m/s        239 m/s
Rotation period          synchronous  synchronous
Axial tilt                 zero          zero
Temperature               86 K          75 K