Archives

A report of the Comet Section (Director: N. D. James). In this report, observations of the brighter or more interesting comets at perihelion during 2016 are described and analysed, concentrating on those visually observed. Magnitude parameters are given for all comets with observations. Any evolution in the magnitude parameters of those periodic comets with multiple returns is discussed. Additional information on the comets discussed here, and on other comets seen or at perihelion during the year, may be found on the Section’s visual observations web pages.

Gamma-2 Andromedae, the blue partner in the beautiful coloured double star Almach, is itself one of the most famous revolving binaries in the heavens: O-Epsilon 38. Always a challenging target for visual observation in sub-metre-class telescopes, this system has recently been going through periastron and has been irresolvable. As it begins to open out again, the time seems ripe to present the author’s observations of the last 26 years, as an encouragement to others to follow this beautiful but difficult orbital system.

During the 2018 Mars opposition a global dust storm developed in the period from May to July and declined again in September. Interestingly, when the storm vanished an accumulation of dust could be detected at several locations, including the Valles Marineris region. In order to correlate local topographic features with the distribution of dust we have investigated the nature of the Valles Marineris terrain using ArcGIS software and detailed elevation data. Spatial analysis using ArcGIS seems to be a useful tool to obtain more insight into dynamic features on Mars and other planets.

Prof Jean Dragesco (b. 1920) gained a worldwide reputation as a photographer of the microscopic scale to the macroscopic. Protistologist by profession and amateur astronomer by inclination, his solar, lunar, planetary and cometary photographs have been admired by a generation of BAA members. This short paper celebrates the centenary of his birth.

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.

R. L. T. Clarkson (1889–1954) lived nearly all his life in Suffolk and the surrounding counties, under the dark skies of rural England. A complete set of beautifully illustrated observational notebooks allows us to trace the life of this typical and uncontroversial amateur astronomer, along with his interactions with the BAA. Throughout most of his life Clarkson suffered from a shortage of money and was even forced to sell his best telescopes during the Great Depression. Some previously unpublished details are presented here about the work of the lunar observer H. G. Tomkins of Dedham, with whom he collaborated in the 1920s & ’30s. Like Tomkins and many others of his epoch, Clarkson favoured a volcanic origin for the lunar craters: the subject of his only contribution to our Journal. Late in life, he was a founder member of the Ipswich and District Astronomical Society, the forerunner of the modern Orwell Astronomical Society Ipswich.

During the 2018 apparition we imaged Mars on the island of Curaçao (E. S.) and from the Netherlands (J. S.), using Celestron C8 and C14 Schmidt–Cassegrain telescopes, respectively. Since the altitude of Mars was the highest on Curaçao and this Caribbean island often has excellent seeing conditions, the most detailed information was collected there. Starting at the end of 2018 May, a big dust storm developed, which at the end of 2018 June covered almost the entire martian surface. In 2018 September the storm had vanished again.