This domain has been of great interest in 2020-2021, with the cyclical birth and transformation of STB structured sectors, proceeding partly as before but partly in a new way; and with v-hi-res observations of these events, from both amateur images and spacecraft  images.  The main developments were preceding oval BA, where one cyclonic spot from 2020 (DS6) transformed into a white oval (WS6); another cyclonic feature, called Clyde’s Spot (DS7), has become an expanding turbulent region with dark spots and disturbance emanating from it; and a third cyclonic spot (Spot 8) erupted in exactly the same way as Clyde’s Spot the previous year. 

We have not posted a substantial report on this domain since our 2020 Report no.4 (2020 July), but there were no major changes from then until this year, and our reports on Juno perijoves (elsewhere on this web site) give updates on subsequent developments.  Now, this report describes amateur observations in the 2021 apparition from early April to late November, plus information from JunoCam perijoves throughout the year, and Hubble (OPAL) imagery on 2021 Sep.4.  

The text of the report is here:     STempR-2021_Report-no-5_text.pdf

Table 1 and miniatures of the figures are here:     STempR-2021_Report-no-5_Mini-Figs.pdf

The full-size figures are here:     STempR-2021_Report-no-5_Figures.zip

Below is Figure 3, which gives an overview of the important features.

Note from the author:   This report, like many of our postings, is quite long and detailed, and includes a large number of figures with numerous images or maps.  I know this is more than most readers will have time to look at, but I make no apology for this.  It is partly due to pressure of time: as all authors know, shortening of material to some arbitrary length is time-consuming and unrewarding, so it would reduce rather than enhance the information that we can publish.  For posting on the internet, it also seems unnecessary, as space is not limiting.  The report includes a summary.  I am pleased to include numerous images, without severe cropping, partly because this enables interested readers to get a good picture of the data used, and partly because observers always like to see their images included.  (As always, images are copyright to the observers named, and the composite and annotated figures are copyright to the people credited and/or to the BAA.) –John.