As NASA's Cassini spacecraft hurtles toward a July 1, 2004 rendezvous with Saturn, the Hubble Space Telescope continues snapping breathtaking pictures of the solar system's most photogenic planet. This latest view, taken on March 22, 2004, is so sharp that many individual ringlets can be seen in Saturn's ring plane.
Though Hubble is nearly a billion miles farther from Saturn than the Cassini probe, Hubble's exquisite optics, coupled with the high resolution of its Advanced Camera for Surveys (ACS), allow it to take pictures of Saturn which are nearly as sharp as Cassini's wide-angle views of the full planet as it begins its approach. Of course, Cassini will ultimately far exceed the resolution of Hubble during its close encounter with Saturn; indeed, Cassini's sharpness began to surpass Hubble's when it approached to within 14 million miles (23 million km) of Saturn this month.
Hubble camera exposures in four filters (blue, blue-green, green, and red) were combined into this image, to render colors similar to what the eye would see through a telescope focused on Saturn. The subtle pastel colors of ammonia-methane clouds trace a variety of atmospheric dynamics. Saturn displays its familiar banded structure, and haze and clouds of various altitudes. Like Jupiter, all bands are parallel to Saturn's equator. Even the magnificent rings, at nearly their maximum tilt toward Earth, show subtle hues, which trace chemical differences in their icy composition.
Over two decades have passed since a robotic emissary from Earth last visited Saturn. This was NASA's Voyager-2 space probe, which flew by Saturn in August 1981. But ever since 1990, Hubble has filled in the gap of high-resolution Saturn imaging by tracking storms and auroral activity, and providing crisp views of the ring plane from various angles, as Saturn drifts along its orbit.
Approaching Saturn at an oblique angle to the Sun and from below the ecliptic plane, Cassini has a very different viewing angle on Saturn than Hubble's earth-centered view. For the first time astronomers can compare equal-sharpness views of Saturn from two very different perspectives.
Credits
NASA, ESA and E. Karkoschka (University of Arizona)| About The Object | |
|---|---|
| Object Name | Saturn |
| Object Description | Planet |
| Distance | The semi-major axis of Saturn's orbit about the sun is 9.5 Astronomical Units (A.U.) or roughly 1.4 billion km. |
| Dimensions | The planet (without rings) has a diameter of roughly 75,000 miles (120,000 km) at the equator. |
| About The Data | |
| Data Description | This Hubble image was created from HST data from proposal : E. Karkoschka and M. Tomasko (University of Arizona) |
| Instrument | HST>ACS/HRC |
| Exposure Dates | March 22, 2004 |
| Filters | F439W (B), F502N ([O III]), F550W (V), F658N (H-alpha) |
| About The Image | |
| Color Info | Blue: F439W (B)Cyan: F502N ([O III]) Green: F550W (V)Red: F658N (H-alpha) |
| Compass Image |  |
| About The Object | |
|---|---|
| Object Name | A name or catalog number that astronomers use to identify an astronomical object. |
| Object Description | The type of astronomical object. |
| R.A. Position | Right ascension – analogous to longitude – is one component of an object's position. |
| Dec. Position | Declination – analogous to latitude – is one component of an object's position. |
| Constellation | One of 88 recognized regions of the celestial sphere in which the object appears. |
| Distance | The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs. |
| Dimensions | The physical size of the object or the apparent angle it subtends on the sky. |
| About The Data | |
| Data Description |
|
| Instrument | The science instrument used to produce the data. |
| Exposure Dates | The date(s) that the telescope made its observations and the total exposure time. |
| Filters | The camera filters that were used in the science observations. |
| About The Image | |
| Image Credit | The primary individuals and institutions responsible for the content. |
| Publication Date | The date and time the release content became public. |
| Color Info | A brief description of the methods used to convert telescope data into the color image being presented. |
| Orientation | The rotation of the image on the sky with respect to the north pole of the celestial sphere. |
