The brighter comets of 2013

This report describes and analyses the observations of the brighter or more interesting comets discovered or at perihelion during 2013, concentrating on those with visual observations. 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.

Read more

The North Polar Hood of Mars

The southern boundary of Mars’ North Polar Hood (NPH) was measured from 585 Earth-based images made between 2001 and 2016. This analysis covers the late summer, autumn and winter seasons for Mars’ northern hemisphere.

Read more

A method for deriving Cousins R magnitudes from UCAC4 data

We describe a method for deriving Cousins Rc magnitudes from r, B, and V stellar photometry in the UCAC4 catalogue, valid in the range 9 < Rc < 16. The source of the majority of UCAC4 reference star photometry is the AAVSO Photometric All-Sky Survey (APASS) catalogue. Version 433 of the software Astrometrica is updated so that, provided the UCAC4 catalogue is selected as the reference, Rc magnitudes are calculated using our derived transformation, namely: Rc= r – 0.108(B–V) – 0.132.

Read more

James H. Worthington (1884−1980): A quest for totality, observatories & Martian canals

James Henry Worthington became a prominent amateur astronomer during the years preceding the Great War, mainly because of his expeditions to distant solar eclipse tracks and observatory sites, but also because of his interest in the Martian ‘canals’ and his friendship with Percival Lowell. Just prior to the start of the War he built a major observatory at Four Marks in Hampshire, which he generously invited BAA members to use whenever they wished, at least until he moved permanently to the USA.

Read more