Thats right, the Great Red Spot was also transiting at the same time, first the shadow made contact with the surface then ganymede itself and then the GRS so for about 2 hours all three were visible at the same time.
----- Original Message -----
From: glennhirsch@No-Spam
Sent: Tuesday, December 25, 2001 5:36 PM
To: sf-bay-tac@No-Spam
Subject: Re: [TAC] Ganymede transit - was there a cast shadow too?
so the clearer, darker tiny disk I saw was the SHADOW and the less distinct, fuzzier tiny disk I saw was the MOON ...?
thanks Phil and happy xmas
----- Original Message -----
From: P T Chambers
To: sf-bay-tac@No-Spam
Sent: 12/25/2001 5:08:41 PM
Subject: Re: [TAC] Ganymede transit - was there a cast shadow too?
Hi Glenn
Yes, If the moon is over Jupiter from our perspective, it can easily be
harder to see than the shadow. The shadows usually stand out in stark
contrast to the surface of Jupiter.
---------
Phil Chambers [ptchamb@No-Spam] (S.F. Bay Area - Calif. USA)
On Tue, 25 Dec 2001 glennhirsch@No-Spam wrote:
>
> Last night @ 1230am in SF using an 8" dobs with a tak le 7mm eypiece,
> I spied Jupiter through a brief cloud hole -- I had a surprisingly steady
> view @ 175x showing Ganymede's tiny black disk just above the red
> spot.
>
>
>
> I thought I also saw the moon's cast shadow -- did I? Is a cast shadow
> visible during a transit in addition to a moon's silhouette?
>
> Glenn Hirsch
>
This archive was generated by hypermail 2b29 : Tue Dec 25 2001 - 20:37:35 MST