Archives

During this aphelic opposition we received over 6,000 observations from 102 contributors. Small-scale dust activity was evident in the north polar region on several occasions, some events coinciding with the seasonal detachment of Olympia. Later dust activity in the region was associated with the development of the polar hood. At Ls = 154° a Regional storm commenced in Libya–Isidis Regio. The most frequently active site until the 1960s, it remained almost completely inactive – at telescopic resolution – for years. This event occurred seasonally early, but a second Regional event that simultaneously broke out there and in Hellas at Ls = 216° in 2014 October showed typical timing: dust spread west across Noachis and led to a darkening of Pandorae Fretum, as well as a broadening of Mare Serpentis. Short-lived local equatorial storms were recorded over Valles Marineris and Chryse–Xanthe. The entire Ls period over which planet-encircling storms are known to emerge was checked…

In 2018 July the authors visited the Lowell Observatory for five nights, primarily to make observations of Mars and Saturn. In this paper we give a short introduction to the history of the observatory and present observations of these two planets, made using the 24-inch Clark refractor.

In this report, observations of the brighter or more interesting comets at perihelion during 2017 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 visual observations web pages.

This paper compares the BAA white-light measurements made during Solar Cycle 24. The main purpose is to assess whether there are any differences in the recorded long-term characteristics of solar activity for observers who determine the number of groups, the sunspot number and/or the BAA quality number (based on type of group). A comparison is also performed between the International Sunspot Number and the BAA sunspot number.

NEMETODE, a network of low-light video cameras in and around the British Isles operated in conjunction with the BAA Meteor Section and other groups, monitors the activity of meteors, enabling precise measurement of radiant positions as well as the altitudes, geocentric velocities and solar system orbits of meteoroids. The results from observations of the Quadrantid and December alpha Draconid meteor showers during 2012–2019 are presented and discussed.

Eclipse time variations have been detected in a number of post-common envelope binary systems consisting of a subdwarf B star or white dwarf primary star, and cool M-type or brown dwarf secondary. In this paper we consider circumbinary hypotheses of two sdB systems, HS 0705+6700 (also known as V470 Cam) and NSVS 14256825, and one white dwarf system, NN Ser. In addition, and for comparison purposes, we investigate the eclipse time variations of the low-mass binary system NSVS 01286630 with its stellar circumbinary companion. All four eclipsing systems have claims of circumbinary objects with computed physical and orbital parameters. We report 108 new observations of minima for these systems obtained between 2017 May and 2019 September and combining these with all published data, we investigate how well the published circumbinary object hypotheses fit with our new data. The new data have shown departure from early predictions for three of the four systems, but it is premature to conclude that these results…

Maria Mitchell (1818–1889) was the first American woman who could truly be described as an astronomer and the first American to be credited with the discovery of a comet. In the mid-19th century, much kudos was attached to finding new comets and the international recognition Mitchell received after being awarded one of the King of Denmark’s medals for her discovery contributed to raising the worldwide standing of American astronomy, adding to the momentum driving professionalised astronomy forward in the US.

Betelgeuse has been the focus of considerable recent attention – even from the mainstream news media – due to its recent deep minimum, to the extent that 10% of all the light curve data on the star in the AAVSO archive, extending 126 years, have been obtained in just the last six months. While it is not impossible that Betelgeuse will become a supernova in the next few years or decades, what we know about the star makes this unlikely. A large part of the uncertainty comes from the fact that neither the mass nor the distance are well-established. It is not even certain that Betelgeuse will become a core-collapse supernova. Overall, the star appears to have brightened significantly over the last 60 years, but the evidence for similarly deep minima in 1946, 1947 and 1984 relies on fragmentary data and single observers. The entire extreme historical range of Betelgeuse from magnitude 0.1–1.6 appears to have occurred in just the last three years.

A report of the Mercury & Venus Section (Director: P. G. Abel). Presented here is a short report discussing the observations communicated to the Director regarding the transit of Mercury which occurred in 2019. A number of interesting features were recorded by those BAA members who were able to observe the transit, which was a difficult one for UK-based observers.

The chance discovery of a letter from T. G. E. Elger (1836–1897) to the telescope maker G. Calver (1834–1927) has shed further light on Elger’s time at Manor Cottage, Kempston, Bedfordshire, between 1881 and 1890. This has enabled additional information to be added to the author’s biographical paper previously published in the Journal.1 The period he spent in residence at Manor Cottage appears to have been an important time in Elger’s life, both in relation to his continued support of selenography and to the establishment of the BAA Lunar Section.