[Illustration: Voyager 1 discovered the rings of Jupiter on March 4 in a single eleven-minute exposure with the narrow-angle camera. Spacecraft motion during the time exposure streaked the picture, as can be seen from the hairpin-like images of the stars. (The star field was unusually rich, since it happened to include the Beehive star cluster in Cancer.) The ring image itself is a multiple exposure, with six separate images side by side. The ring does not extend out of the right side of the picture, indicating that this image captured the outer edge of the ring, about halfway between the cloud tops and the orbit of Amalthea. [P-21258]] [Illustration: Camera with fields of view] Wednesday, March 7. At the press briefing, Brad Smith made a spectacular announcement: “This morning I would like to add yet another important discovery to be claimed by this outstanding mission—that of a thin flat ring of particles surrounding Jupiter. Thus Jupiter now joins Saturn and Uranus to become the third planet of our solar system known to possess a planetary ring system and leaves Neptune as the only member of the group of giant planets without a known ring. The discovery of the ring was unexpected in that the current theory which treats long-term stability of planetary rings would not predict the existence of such a ring around Jupiter. The single Voyager camera image which recorded the ring was planned by the Voyager Imaging Team several years ago, not really with any great expectation of a positive result, but more for the purpose of providing a degree of completeness to Voyager’s survey of the entire Jupiter system. The observation, as planned, involved looking off to the right of the limb of Jupiter in the planet’s equatorial plane at the exact moment that the spacecraft would be crossing the equatorial plane. The image actually was taken at 16 hours and 52 minutes before encounter from a distance of about 1.2 million kilometers. Exposure time was 11.2 minutes. We weren’t certain of the exact moment that we would cross the equatorial plane, so we planned to open our shutter and leave it open as we went through.” [Illustration: Since the Voyager 1 ring photograph was taken exactly edge-on, it was not possible to determine the width of the ring. In this artist’s conception, the ring is drawn as if it were ribbon-like, with very little width, quite unlike the broad flat rings of Saturn. Voyager 2 later showed this to have been a lucky guess. [P-21259]]