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The Journal of the British Astronomical Association, 2020 October

Volume 130, Number 5

Behind a special cover designed by space artist David Hardy is a packed issue, from observing Mars at opposition to getting involved with researching star formation.

Log in or join the BAA today to view this journal online. A full list of contents is also available.

Selected highlights from this Journal:

Notes and News

Life in the Venusian clouds?

Paul G. Abel

Revealing the anatomy of C/2020 F3 (NEOWISE)

Robin Leadbeater

A brief primer on filters

David Arditti

BAA Update

Gordon Ernest Taylor (1925–2020)

Tim Haymes

Observers' Forum

Observing carbon stars with large binoculars

Shaun Albrighton

Refereed Papers

Investigating the Mars edge-rind artefact

The edge-rind artefact is a spurious defect commonly affecting the appearance of the sharper limb of Mars in digital images. Although frequently seen, very little has been written about its appearance or cause. This paper is an attempt to remedy this. It proposes that the artefact is primarily a diffraction effect, whose severity is related to the relative visibility of the Airy disc pattern, and accentuated by contrast-enhancing processing methods commonly used in planetary imaging. The artefact is possibly modified by effects such as variations in seeing, tube currents, optical aberrations or misalignments, as well as the presence of albedo regions ‘hidden’ at the edge of the planet.

Martin Lewis

Thomas G. E. Elger at Kempston – nine years that ‘saved’ amateur selenography

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.

Nigel Longshaw

The 2019 transit of Mercury

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.