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The Journal of the British Astronomical Association, 2019 June

Volume 129, Number 3

An asteroid with a mysterious backwards orbit, an aurora expedition caught up in a major incident at sea and how to observe the home of an iconic black hole. 50 years on, we also celebrate the BAA amateurs who supported the Moon landings..

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:

Refereed Papers

The brighter comets of 2014
This report describes and analyses observations of the brighter or more interesting comets discovered or at perihelion during 2014, concentrating on those visually observed or discovered by amateur observers. 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 Comet Section’s visual observations Web pages.
Jonathan Shanklin
The eastern & western elongations of Venus, 2007–’17 II. The nocturnal hemisphere
Results for the planet’s dayside were described in Part I. Here we discuss the nocturnal hemisphere, with details of infrared thermal emission (IRTE) imaging and the Ashen Light (AL). Images of the IRTE revealed up to nine topographic features upon the surface of the planet and enabled the slow rotation rate of the surface to be measured for the first time from amateur images. D. Gasparri recorded subtle, IR-absorbing low-altitude clouds of large scale, which were more prominent in 2009 than in 2017. The 2017 inferior conjunction saw remarkable high resolution reached by P. Miles & A. Wesley: the small bright spots they resolved upon the planet’s surface might provide evidence for active volcanism. The AL was recorded in a small number of visual observations, with only a few sightings confirmed by a second observer. The few positive AL sightings seem to be linked to solar Coronal Mass Ejection events. We review possible mechanisms to account for the AL.
Richard McKim
Jupiter’s North Equatorial Belt & Jet: III. The ‘great northern upheaval’ in 2012
Paper II described the extreme changes in Jupiter’s North Equatorial Belt (NEB) which took place in 2011–’12: quiescence, narrowing and fading of the belt, along with acceleration of the prograde NEBs jet to super-fast speed. Here we describe how this anomalous state was terminated in 2012, in a rapid and vigorous disturbance known as an NEB Revival – the first in living memory. At the same time, the North Temperate Belt (NTB) had entered a similar preparatory state, which was terminated by an NTB Revival initiated by a typical outbreak on the super-fast NTBs jet. The two concurrent Revivals appeared to constitute a ‘great northern upheaval’ extending from the equator to ~38°N, which may have been the first such event ever recorded. We compare this dual event with the more typical ‘global upheavals’, which consist of near-simultaneous Revivals of the NTB and the South Equatorial Belt (SEB), along with equatorial coloration. We also discuss the current understanding of global upheavals.
John H. Rogers & Gianluigi Adamoli
The exceptional asteroid 2015 BZ509
Data regarding (514107) 2015 BZ509, a retrograde co-orbital asteroid of the planet Jupiter, is presented and discussed.
Jean Meeus