NEW YEAR-------NEW THRILLS

LASS hosted the first observing party of 2012 last Saturday night and it was a booming success.  Six regulars and two guest spent the early evening hours looking at Jupiter, Venus, and Orion as well as a host of other nice targets.  The Goat Hill Clear Clock site that is nearby indicated that we would have good viewing until about 9 PM and as usual, they were accurate almost to the scary point.  Early evening viewing was outstanding so all of us took full advantage of the opportunity.


I had checked the Heavens Above web page for chances to see any of the major satellites and Iridium flares---nothing was going to be available along those lines so I looked at my planetarium program for unusual things that we might want to observe.  I didn't see anything special so we just planned on doing the usual Messier things  and visiting.  After all, visiting is a very major part of the LASS program.  Early in the session most of us took a quick look at Jupiter and noticed that only one moon was actually visible.  We talked about this for a little while and then went about the task of looking for something else.  What we didn't realize was something special was taking place around Jupiter and we weren't even aware of it.  At least we hadn't checked it out and we didn't  know what was actually going on around the big planet.  All of this emphasizes the importance of having a thorough observing plan for every time you go out to look.


Less than an hour into the session someone checked on Jupiter again and made the discovery that one of the moons was just making its appearance from behind/in front of the big red giant.  We all gave it a quick look and within a couple of minutes a second moon appeared on the opposite site of the disk.  Suddenly we realized that we were seeing something very rare and we began to pay a lot of attention to the proceedings.  Within a very short time the fourth moon appeared but it wasn't from behind Jupiter but it appeared almost without warning at a distance from the planet.  To sum it up, we went from one moon visible to all four moons visible within a very short time.   I noted the time that all this was taking place and the next day consulted my trusty planetarium program for an explanation.  Here is what I found.


When we began the observing session shortly after sunset, but before full darkness, we were observing Jupiter with its moon Callisto in all their beauty.  Europa was already transiting the face of the planet but since we weren't aware of that we didn't look for it.   At 6:29, Ganymede emerged from behind Jupiter and we were lucky enough to be looking at almost the exact time that event occurred.  Then at 6:42, Europa completed its transit of the planet and showed itself on the opposite side of Jupiter from Ganymede.  It was almost impossible to tell that both moons were not touching the outer rim of Jupiter at the exact same time.  From 6:15 to 6:42 we went from only one moon visible to three visible.  Then something else happened that we didn't know until the next day when I checked the planetarium program.  At 6:55 shadow of Europa began a transit across the face of Jupiter.  I will admit that it is very hard to follow one of the moons as it transits the face of the planet but the shadow is fairly easy to detect and follow---that is if you know it is going to cross.  By now some of us were getting curious as to the location of the fourth moon and when it might emerge from behind Jupiter.  At 7:51 we had our answer but it wasn't exactly what we were thinking.  It appeared very quickly as the outer most moon---not even anywhere near the edge of Jupiter.  It had not been behind the planet at all but was being eclipsed by Jupiter's shadow.  Then as a final event for Jupiter's evening, the shadow of Europa fell off the edge of Jupiter at 9:13 PM.  Quite a lot of moon activity for one evening.


What is the moral of this narration you might ask?  SIMPLY THIS---if I had looked at the planetarium program in detail I could have been aware that all this Jupiter activity was going to happen.  We did see very part except the shadow of Europa but it was by accident only---nothing that we had planned.  It was neat to see the events unfold as they happened but it would have been a little more exciting for me if I had been aware of how they were going to appear in my scope.  And I always get a special thrill when I watch one of the moon shadows cross the face of Jupiter.  We missed that opportunity by not checking and planning.  I hope to do better in the future.


Incidentally, we did see some great views of Venus and Orion.  Our guest seemed to have a good time and thought they would be coming back again.  But just on schedule according to the Goat Hill Clear Clock prediction, the clouds began to move in shortly after 9 and that ended our first observing session for 2012.  I am looking forward to many more this year.  Hope you can join us for some of them.