Hello Bill,

on the evening of Nov. 12th 2010 (UT) a rare partial eclipse of Kallisto was
observed by Bernd Gaehrken, Munich; see http://www.astrode.de/23kal13.htm
(a translation by Google is available too).

The question / discussion is: how is the observed magnitude drop explained by the
different shadow models of Guide and Celestia. Bernd Gaehrken states that Guide
is using a sharp edge for Jupiter to produce it's shadow and Celestia does not.

Could you give some more insight in this matter?

Thanks in advance and clear skies
Bernd

Bernd Brinkmann

Sternwarte Herne, MPC code A18
Herne, Germany

e-mail: info@...
http://www.sternwarte-herne.de