Fragment L Impact on Jupiter

Andy R x9790: Observations of L impact site                  20 Jul 1994 06:02
  Observations from Warren Rupp Observatory, Mansfield, Ohio

  On the night of July 18-19, we observed the impact sites from 
  fragments C, A and E (oh, this is SL9 hitting Jupiter, in case
  you hadn't guessed) with a 31-inch Newtonian belonging to the
  Richland Astronomical Society.  Although changing seeing 
  conditions and the different placements of the spots make a 
  definite determination difficult, the A spot seemed the weakest
  of the three.  The C and E spots were both also observed through
  the 31-inch's 6-inch finderscope and a 8-inch Edmund.  There was
  also observations of a dark spot through a 3.5 inch Questar, 
  though your humble writer didn't see them. :)

  Tonight, the night of July 19-20, seeing was excellent, and we 
  obtained potentially the only color images of the L impact spot
  on its first pass around the planet, using a color video camera.
  Both the L and G spots were visible early in the night, and both
  were seen to have a dark halo around a central dark core.  The L
  spot seemed as large or larger than the G spot, and both seemed
  to rival the Great Red Spot.  Both spots were easily visible 
  through a 10-inch Meade, but not through binoculars :)  Later in
  the night, after L had rotated out of view and as G was doing the
  same, we observed the H spot coming in to view.  Although clouds
  and Jupiters position in the sky conspired to cut our observing
  off shortly thereafter, the H spot seemed to be rather less 
  distinct than either L or G.  

  Again, we potentially have the best video of the L spots first
  meridian crossing, but unfortunately, we don't know how to 
  distribute this in a timely fashion.  If you can help, please
  E-mail.

  Thanks and happy observing!
  -Andrew Rivkin, Larry Lebofsky and Warren Walker

-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>-<*>

H.Yano: SL9 Pre-Fragment L Anomaly?                       Wed, 20 Jul 94 02:41
Events Caused Over-saturation of Visible-Near IR CCD around L Impact Period?

With local amateur observers, we observed an Earth-size dark spot with
a 14-inch Cassegrainian telescope with a conventional CCD detector at
400-500 nm from 20:00 UTC to 21:30 until it was hidden to the limb.
The seeing was clear with no clouds and we could spot the Jupiter an 
hour prior to the local sun set.  

About 21:30, the CCD suddenly over-saturated and showed a way beyond
its detection limit of intensity.  It lasted 1-2 minutes.  We tried to
solve this but by 21:35 it disappeared and the detector returned to
normal.  There seemed no hardware nor software failure.  Around this time,
a larger spot came above the other side of the limb (Fragment K spot?
Or any of previous large spots?  We need a confirmation from continuous
observers.).  

Fragment L was predicted to impact at 22:08:53 on the 19th July (by
Chodas and Yeoman) and we did encounter with another over-saturation around
22:07 and it became normal back again shortly after that.  As we did not
have previous observations, we would very much appreciate it if other
astronomers could confirm (1) if they also detected the similar phenomena
and (2) which impacts produced the two spots we observed.  If they were
from active spots on the Jovian atmosphere, they might be due to sharp
intensity rise at the moment of which the active spots came above the limb
or went below the limb.

Hajime Yano
Unit for Space Sciences
University of Kent at Canterbury 
Canterbury, Kent, England, United Kingdom
Fax: +44-227-762616
E-mail: hy@ukc.ac.uk