Archives

A report of the Aurora & Noctilucent Cloud Section (Director: Sandra Brantingham). A summary, by the Assistant Director of the Section, of noctilucent cloud (NLC) activity observed during the 2018 season.

Solar prominences were used to track the orientation and meridian bearing angles of their associated filaments over a nine-year period. Since filaments lie at right angles to the prevailing magnetic field, they were used as ‘compasses’ to plot its direction. The field lines marked by the filaments diverged from the meridian symmetrically, eastward and westward, with maximum divergence near the solar poles. The net mean field direction, over nine years, lay closely aligned with the N–S solar meridian. Filament formation was nevertheless asymmetrical, with an excess of filaments whose fields were directed westwards of the meridian. Asymmetrical filament formation appeared to be cyclical, as the proportion of westward-diverging to eastward-diverging filaments peaked during high sunspot activity, suggesting an interaction between the Sun’s poloidal and toroidal magnetic fields.

A report of the Saturn, Uranus & Neptune Section (Director: M. Foulkes). This report describes observations of Saturn made by members of the since-renamed Saturn Section during the 2005/2006 apparition. In particular, this report describes the observations of a bright storm that appeared in southern mid-temperate latitudes, which was also observed by the Cassini spacecraft. Details of other storms observed are also described, including a light spot at high southern latitudes. Only a small segment of the northern hemisphere was visible but within this, a narrow bright blue zone was recorded. Observations of an occultation of the star BY Cancri are also presented.