1540n 2013/10/11–12

1540n 2013/10/11–12 00:30–01:05 Foxmead POD 9 28cmsc

Jupiter triple shadow transit

I started observing when Jupiter was very low (altitude 7.0°) so the seeing was poor, and there was a lot of atmospheric chromatic dispersion. As time went past, the seeing gradually became better, and Callisto's large shadow on the South Polar Region became evident, looking  like a bite out of the disk. Finally, Io's shadow became clear at 01:03.

I had deliberately not checked the shadow positions before going to the eyepiece. On checking afterwards with Starry Night, it turns out that I had missed Europa's shadow completely! What I thought was Europa's shadow was probably a dark barge in the North Equatorial Belt. Oh well, two out of three isn't bad! Most of the observations were made at 175x. The seeing was not good enough to tolerate 255x.

 [Starry Night reconstruction @ 01:03 EDT]

While Jupiter was rising, I also observed the Orion Nebula @70x, and Castor and 38 Geminorum at @255x. 38 Geminorum B had a definite violet tinge.

Temperature = 4.3°C