From John Rogers
Date: Wed, 24 May 1995 11:29:08 +0059 (BST)
Subject: Impact belt still visible
Greetings again. Here is an excerpt from an interim report on Jupiter in 1995 which I have just written for the BAA, giving visual observers' view of the present status of the dark belt in impact latitudes.
It is interesting to compare these observations with the Hubble S.T. map, made on 1995 Feb. 13 at 410 nm (violet), which Amy Simon, Reta Beebe and Nancy Chanover presented at the STScI/IAU Colloquium in 1995 May. The impact belt is not obvious, in contrast to visual observations! However, in the hemisphere where we see a strong belt, the HST map shows dark material over much of the S.S.S. and S.S. Temperate latitudes, but it has sharp irregular boundaries and internal cyclonic circulations that look just like the normal belt features. I suspect this belt is at the normal cloud-top level, comprising an unusually dark SSSTB, but either it is overlaid by a very diffuse dark haze from the impacts, or (more interesting and perhaps more probable) the dark impact material has mostly settled into the troposphere, and has been removed from anticyclonic circulations by convection in the clouds, but remains as a dark stain in the belt regions.
Addendum: On May 19, I viewed the GRS side of the planet and there did appear to be a distinct impact belt there, which was darker following the GRS.
British Astronomical Association.
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