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Saturn Ring Plane Crossing - May 22, 1995


Hubble Space Telescope

New Saturn moon discovered by the Hubble Space Telescope!

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Images Taken by the Hubble Space Telescope on May 22, 1995 during the Saturn ring plane crossing. Click on each image for more detailed information.

Catalina Observatory

The faint Saturn E ring shows in this coronagraphic image from three co-added 300 sec Cousins red-band exposures taken on May 22.5 UT with the Catalina 1.5-m telescope in poor seeing by Steve Larson. The bright satellites Tethys and Dione are to the east (left), and a field star is on the far right. The brightest part of the E ring extends to the orbit of Enceladus and the faint extension can be traced to 6 Saturn radii.

Phillips Laboratory, Hawaii

This observation was made with the 1.2m telescope at the Air Force Maui Optical Station(AMOS) on Haleakala, Maui. The image is a 300 second exposure using a methane band filter. These raw images were taken on May 25, 1995 and no processing has been perfomed on them. People involved: AMOS, JPL, Steve Larson.

Pic du Midi Observatory

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These observations are made with the 105 cm telescope at Pic du Midi observatory with a CCD camera equiped with an I-band filter. The observers are : Francois COLAS, Jean Lecacheux, Sylvie Jancart, Bruno Sicardy, Didier Tiphene. The images are processed by a Lucy-Richardson filter. Observations are made at 60 degrees from the sun. For the image at the exact time of the plan crossing, the sun was at 6 degrees above the horizon.

Texas A&M Observatory

This photo was taken with a 14" Schmidt-Cassegrain at prime focus. The negative was over exposed to show the faint rings. Titan can be seen to the far left, Rhea to the right, and Dione and Tethys are barely visible just to the left of the planet. The photo was taken at 10:03UT, May 21, 1995 by Chris Dahl at Texas A&M Observatory.

Chris Dahl


On May 21, 1995 at 10 UT, I had the opportunity to observe Saturn. This was about 19 hours before the predicted time of Earth's passage through the ring plane of Saturn. The rings were visible with a 14" Schmidt-Cassegrain (f/11) telescope and appeared as a thin dim line. The shadow of the rings and the north and south equatorial bands were visible on the planet. Titan, Rhea, Tethys and Dione were also visible.


On May 22, 1995 at 9:30 UT (about 4 hours after the ring plane crossing) I could see no trace of the rings of Saturn except for the its shadow which was south of Saturn's equator as it was the night before. Titan, Tethys and Dione were also visible. I found out later that Rhea was in front of the planet. On both mornings, Saturn was a great deal dimmer to the naked eye than it had appeared a months earlier. I had not expected such a drastic difference in brightness. The observations were made just west of College Station, Texas at the Texas A&M Observatory.

Dan Bruton
Texas A&M


Richard Schmude took this photo on June 13, 1995 at 9:47 UT using a 35mm camera on a 14" Schmidt-Cassegrain Telescope (f/11) with a 7.4 mm eyepiece (5 second exposure). This photo was made at the Texas A&M Observatory.

University of Hawaii

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May 14 (UT) 2.1 micron image - obtained by Kevin Jim and Andrew Pickles; image processing was performed by Richard Wainscoat. This image was made using the University of Hawaii's 2.2-meter telescope with its tip-tilt secondary mirror in operation (guiding on the satellite Tethys). The tip-tilt guiding removed some of the atmospheric distortion, and also removed buffeting of the telescope by a moderate wind from the east. Exposure time was 8 seconds through the K' filter. Saturn is relatively dark around 2 microns due to methane absorption in its atmosphere. This image has a resolution of 0.50 arcsec, and was taken at an airmass of approximately 1.9. Two satellites may be seen to the left of the rings - these are Tethys (brighter) and Enceladus (fainter). The shadow of the rings produces the dark line across Saturn's equator. A false color version of this image is also available.

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A deconvolved version of the May 14 image is now available, and is also available in false color. Since no true point source was available, Tethys was used as the point source for this deconvolution. Tethys is not quite a point source (diameter 0.145 arcsec), so some low level artifacts result from the deconvolution.

May 20 (UT) K-band image (2.2 micron) (17k). This is a 1-second sky-subtracted exposure, displayed with a logarithmic stretch. North is at the top, and east is at the left. To the east, Rhea and Tethys (farthest east) may be seen. West of Saturn is Enceladus. This image was obtained by Christophe Dumas, Natalie Domergue-Schmidt, Joe Jensen, and John Dvorak at the University of Hawaii 2.2-meter telescope.

May 21 (UT) J-band image (1.2 microns) (7k) which shows the very faint E-ring. The integration time was 11 minutes and the image was taken at approximately 14:45 UT (about 50 minutes before sunrise). The bright spot on the left is Rhea, and is saturated in this deep exposure. The scattered light comes from the A ring and Saturn. This image was taken through thin cirrus. The observers were Christophe Dumas, Natalie Domergue-Schmidt and John Dvorak.

May 22 (UT) K-band image (2.2 microns) constructed from six 60 second exposures. The dark side of the A-ring is visible; the satellites are slightly elongated because of their orbital motion during the exposure. The contrast has been modified to try to show very faint satellites such as Helene (about K=17.5), and Janus (about K=14), located inside the A ring. The observers were Christophe Dumas, Natalie Domergue-Schmidt, and John Dvorak; the image was obtained with the University of Hawaii 2.2-meter telescope.

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Ron Baalke