2017 April 18

Juno’s closest fly-over at perijove-5

John Rogers

Juno had another successful pass over Jupiter at its fifth perijove on 2017 March 27, coming closer than ever before; the altitude of the highest-resolution image was only 3422 km.  The BAA Jupiter Section has posted a report on the close-up images taken by JunoCam, annotated with features recognisable from ground-based tracking, at:

https://britastro.org/node/9891

As this was close to Jupiter’s opposition, there were many high-quality amateur images and maps to provide context.  The best amateur maps now include white ovals at extremely high latitudes: one at ~72ºS which has now been tracked for over a year, and a pair at ~60ºN which are now interacting. 

The JunoCam images are now accurately mapped thanks to Gerald Eichstädt. At this perijove, the majority of JunoCam images were reserved for the polar regions, so that time-lapse animations of the circulations there will be produced by the JunoCam team. 

Five images were close-ups of the lower latitudes, as selected by the public, and they included two of the most interesting features: the North Temperate Belt, which has been reviving as a  ‘Big Red Stripe’ since its great outburst of activity last autumn; and the ‘STB Spectre’, a long-lived cyclonic circulation.  Both these were beautifully imaged; the figure below shows the STB Spectre.