Saturn Occultation of 28 Sagittarii (Sge)
on July 3, 1989

This 9-second animation (top left) covers 40 minutes in real time between 05:50:00 and 06:30:00 UT (5 hours UT is 10pm PDT) showing outer rings passing over the star. As this sequence progresses the observer notices that the star never totally disappears behind the rings. The variation of the star's brightness reveals unseen (by the eye) detail in Saturn's ring system and atmosphere. In the original VHS video tape that Bill Hornaday, a member of the JPL Infrared Imaging Group and long-time member of SRO, made of this entire event spanned 3 hours 37 minutes. A total of about 325,000 video frames were taken that night. The images are not particularly sharp due to bad seeing conditions and the dozen bodies in the dome causing heat to rise through the open telescope tube.

This sequence (bottom left) started about 2 hours after the end of the first sequence and ended 40 minutes later. in the early part of the sequence one can see the star 28 Sge emerge from behind Saturn. The blinking of the star is due to inversion layers in Saturn's atmosphere. There's a gap in the time-line where the image of Saturn jumps a bit. The image (above right) shows the first part of the sequence in higher time-resolution for the egress event.
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