Papers – Page 15 – British Astronomical Association

Visual measurements of the proper motions of 61 Cygni & Groombridge 1830 using an undriven 10-inch Dobsonian telescope

Results of visual measurements of the proper motions of 61 Cygni and Groombridge 1830, using an undriven 10-inch (250mm) Dobsonian telescope and an astrometric eyepiece, are presented. It is shown that reasonably accurate measurements of the proper motions of these stars can be made visually, using simple equipment, over a period of time that is less than two years.

The brighter comets of 2012

This report describes and analyses the observations of the brighter or more interesting comets discovered or at perihelion during 2012, 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 Section visual observations web pages.

Saturn in the 2008/2009 apparition: Part I

This report describes the observations of Saturn made by Saturn Section members during the 2008/2009 apparition. During this apparition, the rings were edge-on to the Sun and Earth on 2009 Aug 11 and Sep 4 respectively

A previously unreported naked-eye sunspot observation: 1604 November

Evidence is presented of a previously unreported naked-eye sunspot observation in 1604. A report from a 17th century Hungarian history is analysed and possible alternative interpretations are discussed. Further evidence of high solar activity at the time is briefly examined.

RZ Cas lightcurve and orbital period variations

A binary star model for RZ Cas is fitted to a set of high quality electronic magnitude observations of recent minima, deriving in the process some of the parameters of the system. This lightcurve is then fitted to raw observational data from the BAA, AAVSO, AFOEV and VSOLJ in order to determine the times of minimum. These observed times of minimum supplemented by data from the Lichtenknecker database are then compared to expected times and are shown to be consistent with several significant long-term changes in the period.

The opposition of Mars, 2010: Part I

This report summarises over 8,000 observations by 149 observers between 2009 March and 2010 September, covering martian northern late autumn to winter, spring and early summer (Ls= 232-156°). Part I discusses dust storms and albedo features.

The strange world of V. Axel Firsoff (1910−1981)

Axel Firsoff was one of the most controversial theorists and letter writers in the BAA’s history, submitting huge amounts of correspondence to the Journal between 1956 and 1981 and serving on the Committee of the Terrestrial Planets Section from 1979 to 1981. He was also a successful author, writing more than 20 books from 1942 until his death. In addition, Firsoff was a skilful artist, an accomplished skier, a lunar and planetary observer and an early pioneer in the use of colour filters.

Spectroscopic observation of planetary nebulae

This paper describes how commercially available spectrographs can be used to identify and measure some basic characteristics of planetary nebulae.

Saturn, 2004-’05

The 2004-’05 apparition was very well observed, though the planet showed less atmospheric activity than in the previous apparition. Many images were obtained at visible, infrared, ultraviolet and methane band wavelengths. The planet was at opposition in Gemini on 2005 Jan 13, at declination +21°. Solar conjunctions occurred on 2004 Jul 8 and 2005 Jul 23. Our observers monitored the planet from 2004 Aug 15 (Gray) till 2005 Jun 9 (Yunoki).

Franz von Paula Gruithuisen (1774− 1852) and the ‘Lost City in the Moon’

In the early hours of the morning of July 12 in the year 1822, Franz von Paula Gruithuisen (1774–1852) turned his small telescope to the Moon. What greeted him at the eyepiece, in the environs of the crater named Schroeter, was nothing short of a revelation. The jumbled terrain, caught under raking illumination, coalesced into a regular arrangement which convinced the astronomer he had discovered evidence that the Moon was inhabited….