The Journal of the British Astronomical Association
Volume 108, No.3: 1998 June
List of Contents
On this page: Notes and News / Articles / Letters / Reviews / Meetings / BAA Update
Notes and News
Shadow bands recorded at February 26 eclipse / The total eclipse from Venezuela / Aurora Section / From the President / Bright fireball in southwest England, 1998 March 15 / The discovery of SN1998an / Solar Section / MERLIN's Ring / Cassini is 'go' - but Saturn has the blues
The 1997 Presidential Address: Amateur spectroscopy ... Maurice Gavin
Auguste Comte is remembered for an unfortunate remark. In 1825 he said the chemical composition of stars would never be revealed. Within a decade or so the heart of the atom was being explored in remote stars through the science of spectroscopy. In simplistic terms one can regard the atom as a miniature solar system, but with the novel option that electrons (representing planets) having the ability to 'jump' from one orbit to another. In 'falling' to a lower orbit a photon of light of precise wavelength is released to travel outwards. When the electron 'jumps' to a higher orbit a photon of light is absorbed. This is taking place on a vast scale which we observe as lines in the spectrum - their position and prominence relates to the particular atomic element, temperature and pressure within the stellar atmosphere. It is beyond the scope of this Address to discuss the various processes that affect spectra, or to provide a mathematical explanation which can be found elsewhere. In any case the lack of a deep understanding does not preclude enjoyable or useful observations. (10 pp, 27 illustrations, 5 in colour)
The aurora 1996 ... R. J. Livesey
This report summarises observations of the aurora relating to the northern hemisphere collected in 1996 by members and correspondents of the Aurora Section. (5 pp)
The effect of Delta T on astronomical calculations ... Jean Meeus
Universal Time (UT), or Greenwich Civil Time, which is needed for civil life, is based on the rotation of the Earth. But the Earth's rotation is slowing down and, moreover, this occurs with unpredictable irregularities. For this reason, UT is not a uniform time-scale. However, astronomers need a uniform time-scale for their accurate calculations (celestial mechanics, orbits, ephemerides). This paper describes the effect of these differences on actual observations. (3pp)
Comet C/1996 B2 (Hyakutake): The Great Comet of 1996 ... Nick James
A preliminary report on this comet has already appeared in the Journal and a more detailed set of observations has been published by The Astronomer. This paper records those observations submitted to TA and the BAA up to the end of 1996 October. Whilst there is some analysis here it is not extensive. It is hoped that a final report will be published as a Memoir at a later date. Many of the observations and images have been archived electronically on a CD-ROM. A selection of these observations is also available on the Internet. The visual observations were converted to electronic format and have been forwarded to the International Comet Quarterly. (16pp, 35 illustrations, 7 in colour)
The Gillingham magnetometer ... Tony Rickwood
A description is given of two types of simple magnetometer which may be readily constructed by the amateur for the detection of disturbances in the Earth's magnetic field. (2pp)
Reports and pictures from the solar eclipse of 1998 February 26 ... Hazel McGee et al. (3pp, 6 illustrations, 5 in colour)
(Copies of any of these articles may be ordered from the BAA office.)
- The Leonids from Cambridge in 1799 ... Jeffrey C. Barham
- Frequency of eclipses in the British Isles ... Peter Macdonald
- Aircraft condensation trails ... John Vetterlein
- Solar Eclipse 1999 - Plymouth ... Tom Wildy
Read the letters here
Fire in the Sky: Comets and Meteors, the Decisive Centuries, in British Art and Science by Roberta J. M. Olson and Jay M. Pasachoff. Cambridge University Press, 1998. (Published with the support of Gresham College, London.) ISBN 0-521-630606. Pp. xiv + 369 (hbk).
reviewed by Julian Baum
- Make Your Own Telescope from everyday materials by Reg Spry. South Downs Planetarium Trust, 1998. (Available from S.D.P.T., 46 Central Avenue, Bognor Regis, West Sussex PO21 5HH). ISBN 0-9531 716 04. Pp 48, £4.95 (Pbk.)
reviewed by Rossie Atwell
- Large Scale Structures in the Universe by Anthony Fairall. Wiley/Praxis, 1997. ISBN 0-471-96252-X (hbk), 0-471-96253-8 (pbk). Pp xix + 196, £50.00/£19.99.
reviewed by Stuart Clark
The Observer's Year: 366 Nights of the Universe by Patrick Moore. Springer-Verlag, 1998. ISBN 3-540-76147-0. Pp xi + 368, £19.00, pbk.
reviewed by Alan Dowdell
- Cosmic Winds and the Heliosphere by J. R. Jokipii, C. P. Sonett and M. S. Giampapa (Eds.). University of Arizona Press, 1996. ISBN 0-8165-1640-5 (hbk), 0-8165-1641-3 (pbk). Pp x + 270, $45.00/$19.95.
reviewed by Michael Gadsden
- Ordinary Meeting, 1998 January 21
- Ordinary Meeting, 1998 February 21
- Obituary: Stanley William Milbourn, 1925-1997
Photocopies of articles, or a copy of any recent issue of the Journal may be ordered from the BAA office.
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