At impact sites G and D a dark spot similar in size to the GRS
and slightly elongated in about NE-SW direction was observed on
July 18 from about 19h25 UT on until the region became invisible
near the western Jupiter horizon, using the CCD camera of the
1.2 m telescope at Calar Alto. The spot was clearly visible
through all 4 filters used: B (Johnson), ammonia (648/5 nm),
methane (727/2.5 nm), and narrow continuum (950/11 nm).
About 2 hours after impact of fragment H, a dark spot became visible at impact site H comparable in size to the above mentioned one. Observations were done through the B filter.
The Calar Alto Observing Team: Tom Herbst, Kurt Birkle, Hermann Boehnhardt, Giovanni Calamai, Alex Fiedler, Doug Hamilton, Karl-Heinz Mantel, Jose Luis Ortiz, Andrea Richichi, Ulrich Thiele