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Saturn Ring Plane Crossing - Aug 10, 1995

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Hubble Space Telescope

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Image taken by the Hubble Space Telescope on August 10, 1995 during the second Saturn ring plane crossing. Click on the image for more detailed information.

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Reappearance of Saturn's Satellite Mimas.

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Motion of Saturn's Satellites.

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Brightness Variations in Saturn's Satellite 1995 S5.

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Saturn's E Ring in Ultraviolet Light.


European Southern Observatory, Chile

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The two images presented here were taken with the 256 by 256 IR camera (Sharp II), using the Adonis adaptive optics system attached to the ESO 3.6-m telescope. The field of view is about 12.8 by 12.8 arcsec

Both images were obtained after a 60 sec exposure time in the short K filter, on August 10, 1995, at about 12-13 hours before the expected ring plane crossing (Aug. 10, 20:54 UT). Thus, the dark side of the rings is still faintly visible because of the transmitted solar light and the Saturn shine on the rings.

The East ansa view was taken at 7 h 15 UT. It shows, from left to right, the A ring, the B ring, Janus and the C ring. The West ansa view was taken at 8 h 20 UT and shows, from left to right, the C ring, the B ring, the A ring, and Tethys and Mimas, merged together. This image has a typical angular resolution of 0.3 arcsec.

Note the brightening of the western extremity of the A ring, as opposed to the eastern extremity. Its origin is still unknown. It could arise from a new satellite, or clumpy material in the F ring or Encke gap.

Observers were J.L. Beuzit, P. Prado and B. Sicardy.


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These two sets of images were taken with the Adonis adaptive optics camera installed at the 3.6-m telescope of the European Southern Observatory (ESO La Silla). The short K filter corresponds to a central wavelength of 2.2 microns. Each frame has a width of 10.4 arcsec, and shows the dark side of the rings. Observers were J.-L. Beuzit, P. Prado and B. Sicardy. The images were processed by F. Poulet at Paris Observatory.

The upper panel shows the Western ansa of Saturn's ring, about one day and a half before the Earth ring plane crossing (predicted at Aug. 10, 1995, 20:54 UT). The halo on the left is caused by the light scattered from Saturn. Besides Janus and Rhea, one can see Pandora moving westward (to the right), as expected from the Saturn Viewer of Mark Showalter.

The lower panel shows again the Western ansa, about 12 hours before the ring plane crossing. The left frame shows the brighter B ring and Cassini Division, the fainter A ring, plus a brighter clump at the extremity of the ansa, corresponding to the location of the F ring. The right frame has been obtained by substracting an image of the Eastern ansa. One notes the presence of an unresolved object, identified as the new satellite 1995S6 tracked by the Hubble Space Telescope a few hours after this image was taken (IAUC 6243). In total, 9 pre-discovery images taken at ESO show an object at Eastern and Western elongations, at times expected from the ephemerides of 1995S6 derived by HST.


Nick James

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An image taken on 1995 July 16 just after a Tethys/Dione appulse. The un-illuminated side of the rings can just be seen extending from the over-exposed globe of Saturn. (0.30m Newtonian, Sony CCD, Nick James).

Thomas Collin

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Saturn with Titan at lower left. North is at the top. Picture taken with a ST-4 on a 8" SCT at f/6. The exposure was 0.1 sec (1st image) and 1 sec (second image) at 5 UT on August 19, 1995, 9 days after the ring crossing. The sunlit side is visible. The moons visible in the second image are Titan, Rhea, Dione, (Saturn), Tethys.

Thomas Collin, Quibec



William Herschel Telescope, La Palma

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Image taken at the William Herschel Telescope on August 3, 1995.

University of Hawaii

August 11, 1995

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Aug 11 (UT) R-band coronagraphic image. The ring plane crossing occurred about 15 hours before this 60 second exposure was taken. The A-ring has become remarkably brighter. This is because for the time between the first ring plane crossing on May 22 UT, and the second ring plane crossing (Aug 10 UT), we were viewing the dark side of the rings, but now we are seeing the side which is illuminated by the Sun. The A-ring is thoroughly saturated in this image.

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A direct comparison between Aug 10 UT and Aug 11 UT images, each with the same exposure time, clearly shows how bright the inner rings have become.

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The faint E-ring is still visible in a deeper display of the same image.

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This image can also be viewed with circularly symmetric scattered light subtracted. The bright satellites are, left to right, Tethys, Enceladus and Rhea, to the east of Saturn, and Dione to the west of Saturn.

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The A-ring has now become so bright that only very short exposures with a CCD on a large telescope remain unsaturated. A 5 second R-band exposure, taken about one hour earlier, was the longest exposure which didn't saturate the inner ring. Note that the very bright disk of Saturn, and most of the ring system which we usually see (A, B, C rings), are hidden behind the occulting spot of the coronagraph. The very faint E-ring can still be seen in a deeper display of the same image.

The observer was David Jewitt; the images were obtained with the University of Hawaii 2.2-meter telescope. Only minimal processing has been applied to these data.

August 10, 1995

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Aug 10 (UT) R-band coronagraphic image which shows the faint E-ring. This is a short, 60 second exposure through a red filter. The satellites to the east (left) of Saturn are Rhea (saturated) and Dione (saturated, on ring). To the west of Saturn are Mimas (on the right hand edge of the A-ring), and Tethys (also saturated). Between Mimas and Tethys are the much fainter satellites Helene and Telesto (fainter). A short 10 second R-band exposure (52k), taken 36 minutes later may also be viewed - this image shows more detail of the inner A-ring. A deeper display (82k) is also available, as is a version with circularly symmetric scattered light subtracted.

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A deeper display of the same image shows the E-ring extending out beyond Tethys.

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This image can also be viewed with circularly symmetric scattered light subtracted.

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A short 10 second R-band exposure, taken 36 minutes later may also be viewed - this image shows more detail of the inner A-ring.

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A deeper display is also available, as is a version with circularly symmetric scattered light subtracted.

The observer was David Jewitt; the images were obtained with the University of Hawaii 2.2-meter telescope.

August 9, 1995

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Aug 09, 1995 (UT). R-band coronagraphic image which shows the faint E-ring. This is a short, 60 second exposure. The occulting disk in the coronagraph has a diameter of 30 arcseconds, and the image area shown measures approximately 160 x 160 arcseconds. The bright A-ring can be seen near the edge of the occulting disk. The bright satellites to the east (left) of Saturn are Tethys and Dione.

The observers were David Jewitt and Paul Kalas; the image was obtained with the University of Hawaii 2.2-meter telescope.

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A deeper display of the same image shows that E-ring stretching almost to the edge of the image. The E-ring can be seen extending out to about 7 Saturn radii.

The observers were David Jewitt and Paul Kalas; the image was obtained with the University of Hawaii 2.2-meter telescope.

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A 20 second R-band exposure, taken 90 minutes later, may also be viewed. This image has been processed to remove circularly symmetric scattered light around the occulting disk - it shows the inner A-ring more clearly, and also shows the E-ring extending outward to about 65 arcseconds from the center of Saturn. A faint satellite is visible between Tethys and Dione.

The observers were David Jewitt and Paul Kalas; the image was obtained with the University of Hawaii 2.2-meter telescope.


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Please direct questions and comments about this Home Page to
Ron Baalke
ron@jpl.nasa.gov

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