The Journal of the British Astronomical Association

Volume 122, No.3: 2012 June

Summary contents page

Detailed contents: Notes and News / Articles / Observers' Forum / Reviews / Letters / Meetings / BAA Update


On the cover

Image of Saturn by Anthony Wesley, Murrumbateman, Australia, on 2012 May 4 at 14:31 UT. On page 149 of this issue, Paul Abel helps you get started with drawing the planet, and describes some of the features visible on it with a medium telescope.

Notes and News

From the President (Bill Leatherbarrow ) / The Sky at Night at 55 (Richard Miles ) / Quadrantids put on a good show in 2012 January (John W. Mason) / Solar Section (Lyn Smith) / Supporting Rosetta: a pro-am workshop held at UCL (Richard Miles) / Venus in 2011–’12: fourth interim report (Richard McKim) / Aurora Section (Ken Kennedy) / A ‘wetted layer’ model for cometary nuclei (Richard Miles) / The Radio Astronomy Group in 2011 (John Cook) / A systematic approach to recording night sky quality (John Prockter)

Observing basics: III

  • Visual observation of Saturn ... Paul G. Abel
    ‘Observing basics’ is a series of articles by BAA Section Directors and other experts, designed to help you get started in observing, whether you are a newcomer to astronomy or an ‘old hand’ thinking of taking up a new area of interest. Look out for further articles in the series in future issues of the BAA Journal!

    • Refereed papers

    William Maximilian Lindley: Fifth Director of the BAA Variable Star Section ... Jeremy Shears

    William Maximilian Lindley, MC, MA, FRAS, AMICE (1891-1972) served as fifth Director of the BAA Variable Star Section from 1939 to 1958. He was an active variable star observer for many years and wrote numerous publications on the observations made by Section members. This paper discusses Lindley’s life and work, with a particular focus on his contribution to variable star astronomy.

    Short paper: Modifying DSLR cameras for astrophotography ... Tony Morris

    While digital single lens reflex cameras, DSLRs, can produce high quality colour astrophotographs they have one technical weakness - that is their relatively poor response to the red light of the hydrogen alpha (656nm) wavelength of emission nebulae. This is unfortunate as many targets for the astrophotographer emit at this wavelength. This restriction is in part due to the presence of an infrared (IR) blocking filter that also blocks most of the H-alpha light. To increase the camera’s H-alpha recording efficiency it is possible to remove the internal IR blocking filter. Instructions for doing this for specific cameras are widely available on the Internet and this paper provides some general advice on how to maximise the likelihood of a successful modification.


    Short paper: Fireballs over Iceland ... Thorsteinn Saemundsson

    Late in the evening of 1976 August 1, a spectacular fireball appeared over Iceland. The sky happened to be clear over most of the country and the meteor was widely observed. The day was a Sunday and the following day was a holiday. Consequently, many people were travelling and camping in the countryside and reports came in from many areas. The time (22:40 UT) was after sunset for most observers except those in NW Iceland where the Sun was still above the horizon.


    Short paper: PV Cephei and Gyulbudaghian’s Nebula ... David Boyd

    Gyulbudaghian’s Nebula is one of a small number of variable nebulae which the BAA Deep Sky Section has been monitoring for several years. Each of these nebulae is associated with a pre-main-sequence star which is still in the process of evolving onto the main sequence. These young stars are intrinsically variable as material from a thick, dense accretion disc surrounding the star falls onto its surface in a random, ‘lumpy’ manner. They have strong magnetic fields and, in a mechanism not yet fully understood, they produce energetic bipolar outflows along the rotational axis of the star which impinge on the surrounding clouds of gas and dust.


    Learning from Galileo’s errors ... Enrico Bernieri

    Four hundred years after its publication, Galileo’s masterpiece Sidereus Nuncius is still a mine of useful information for historians of science and astronomy. In his short book Galileo reports a large amount of data that, despite its age, has not yet been fully explored. In this paper Galileo’s first observations of Jupiter’s satellites are quantitatively re-analysed by using modern planetarium software. All the angular records reported in the Sidereus Nuncius are, for the first time, compared with the satellites’ elongations carefully reconstructed taking into account software accuracy and the indeterminacy of observation time. This comparison allows us to derive the experimental errors of Galileo’s measurements and gives us direct insight into the effective angular resolution of Galileo’s observations. Until now, historians of science have mainly obtained these indirectly and they are often not correctly estimated. Furthermore, a statistical analysis of Galileo’s experimental errors shows an asymmetrical distribution with prevailing positive errors. This behaviour may help to better understand the method Galileo used to measure angular elongation, since the method described in the Sidereus Nuncius is clearly incorrect.


    What’s in a name? – ‘Webb’s Furrow’ and a minor correction to Our Moon by H. P. Wilkins ... Nigel Longshaw

    Two unofficial selenographical designations are discussed in the context of lunar studies carried out under the direction of the British Association for the Advancement of Science in the middle of the 19th century. The telescopic appearance of these features is commented upon with reference to the ‘confirmation’ of one of them using Apollo imagery.     Click here to find out how to obtain a PDF file of any of these articles

    Reviews

  • Venus Seen on the Sun: the first observation of a transit of Venus by Jeremiah Horrocks tr.by Wilbur Applebaum,
    Brill History of Science & Medicine Library, 2012. ISBN 978-90042-21932, Pp. xxiv + 82, £85.54 (hbk).
    Reviewed by David Sellers

  • The Construction of the Heavens: William Herschel's Cosmology by Michael Hoskin,
    Cambridge University Press, 2012. ISBN 978-1-107-01838-9. Pp viii + 205, £65 (hbk).
    Reviewed by Mike Frost



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    Observers' Forum

  • Lunar occultations of double stars: a plea for observations ... Alex R. Pratt

  • NGC 6826 – the Blinking Planetary ... Stewart Moore

    •  Right: Image of NGC 6826 obtained by Andrea Tasselli with a 20cm Intes Micro M809 f/10 Maksutov-Cassegrain + SX SXV-H9 CCD. 205x20s L + 24x25s each RGB.

    BAA Update

  • Light pollution & planning controls: a CfDS conference at Leicester DMU ... Bob Mizon

  • The BAA VSS online database ... Roger Pickard & Andy Wilson

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    Meetings

  • Ordinary Meeting, 2011 November 19 ... Hazel McGee

  • Ordinary Meeting & Christmas Lecture, 2011 December 10 ... Alan Dowdell

    •  Why not join us at a BAA meeting near you? Meetings are open to all and you will be made very welcome.   Click here for the latest Meetings Diary

    Letters

  • Unroofing the lunar chasms ... Christopher Taylor & Bill Leatherbarrow

  • A new astronomical dictionary for the deaf ... Abdu Arishi

  • Coma Berenices ... Mike Gainsford

  • Correction – 2011 George Alcock Memorial Lecture ... Gary Poyner

  • Stonyhurst Disks ... J. Eric Jones

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    Sky notes for 2012 June & July by Callum Potter

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