[Tropo-Bob (Bob)]

Callisto

I watched Jupiter over several hours last night with my Vixen 115mm ED (pictured below), as Callistro appoached Jupiter's North Pole. I ceased just after midnight, when Callistro was level with the Pole. I estimated that its distance from the limb was 1/6 to 1/5 (16 to 20%) the size of the Jupiter's North/South axis. The Great Red Spot was clearly visible at this time.

As an aside, I notice how seeing improved greatly after 11pm. Initially, I thought that this was because Jupiter was near the zenith, but a peep at the lower Saturn showed a much better view than I had of Jupiter at the same altitude. However, I had to dial the magnification down on the much lower Mars (about 35 degrees of altitude.) One of its pole caps appeared stikingly visible. (I haven't seen the cap this good for decades.)


Future events, which I will attempt to view:-

1/6 & 2/6 The 'swing' of Io. Near stationary at the furthermost point of its orbit, I am hoping to see some movement in a North-South direction over a few hours as Io approaches or recedes from us in its inclined orbital-plane. I hope this makes sense!