Paul, According to SkyMap, it looks like the shadow you saw near Callisto, was actually the shadow of Ganymede, Which passed over the disc earlier. In fact, Around 1950, Both satellites were visible on the face of Jupiter. Callisto's shadow would not show on the disc until 0128 5 Aug ending at 0515. Here's a table I ran in SkyMap showing the times of the events: <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine6> 2008 Aug 04 17:05 III Transit start <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine7> 2008 Aug 04 19:28 IV Transit start <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine8> 2008 Aug 04 19:38 III Shadow transit start <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine9> 2008 Aug 04 20:18 III Transit end <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine10> 2008 Aug 04 22:55 III Shadow transit end <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine11> 2008 Aug 04 23:03 IV Transit end <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine13> 2008 Aug 05 01:28 IV Shadow transit start <file:///C:\Documents%20and%20Settings\Richard%20Tejera\Local%20Settings\Tem p\SMPLine17> 2008 Aug 05 05:15 IV Shadow transit end Whether it is possible, I won't say, I'd imagine a better alignment of the sun Jupsat system it may, But it looks like tonight you got a moon and a different moon's shadow. Still worth the price of admission in my book, thin as it is ;) BTW, If your Still up around 0230, you should be able to see Callisto's Shadow & Io's Shadow transiting together. Let me know, I'm going to sleep. Clear Skies Rick Tejera Editor SACnews, Public Outreach Coordinator Saguaro Astronomy Club Phoenix, Arizona www.saguaroastro.org saguaroastro@xxxxxxx -----Original Message----- From: az-observing-bounce@xxxxxxxxxxxxx [mailto:az-observing-bounce@xxxxxxxxxxxxx] On Behalf Of Paul Lind Sent: Monday, August 04, 2008 21:29 To: az-observing@xxxxxxxxxxxxx Subject: [AZ-Observing] Two spots on Jupiter Is it possible to see both Callisto and it's shadow both on the face of Jupiter at the same time? That's what seems to be happening right now. There are two dark spots very slowly moving across Jupiter's northern hemisphere. -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list. -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.