Watching Ganymede Disappear

[cloudsweeper]

9.15pm Saturday.  8SE with focal reducer.  Saturn low, south.  Moon (1 day to full) SE, with Jupiter quite close, above.

Moon good at x41 / 1.74deg, not too bright - a bit of detail to the east/terminator.

Then up a bit to Jupiter.  Io and Callisto were west of Jupiter and not in the usual "line".  Europa was a similar distance on the other side.  Ganymede however was close to Jupiter, west of it, and above its equator.  

I raised the mag in steps to x160, and kept watching Ganymede as it disappeared behind Jupiter.  By 9.45, it was "kissing" the planet.  Five minutes later it was just a pimple on the side.  Five more minutes, and it could only just be made out.  Three more minutes and it had gone behind the disc.  

It is quite remarkable to watch these changes taking place over a matter of minutes.  

It is also pleasing to go out and come across something surprising, interesting, and unexpected.  What a great pastime this is!

Just for the heck of it, I directed the 'scope to the Andromeda galaxy, close to the Moon's glare.  Yet there it was, a small, faint, grey patch, at x41 again.

A great little session, ending at 10.05.

Doug.

 

[Mr Spock]

Just watched it come back out. I assume from your description Europa is the one I saw move across the edge of Jupiter and over the surface at around the same time? There were two moons the other side.

[cloudsweeper]

5 hours ago, Mr Spock said:

Just watched it come back out. I assume from your description Europa is the one I saw move across the edge of Jupiter and over the surface at around the same time? There were two moons the other side.

Yes Michael, by about 1.45, Ganymede was on show again, and Europa was starting to move across Jupiter's face.

Doug.

[RT65CB-SWL]

Such an amazing sight when you view one of the Jovian moons going behind or in front of Jupiter’s disc at the eyepiece.

Many years ago all four were eclipsed, then one by one they started to reappear. It was surreal moment of viewing for a few minutes, only Jupiter’s vast disc beforehand and nothing either side, apart from a few faint stars.