The Journal of the British Astronomical Association

Volume 117, No.2: 2007 April

Summary contents page

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

On the cover: A Great Comet!

Comet 2006 P1 (McNaught) photographed in English and Australian skies. Top: 2007 January 10, 17:03 UT. Processed from 9x0.3 sec. exposures, Canon Eos 10D digital camera, 100mm f/3.5 lens. Field of view 10.6x7.2°. Chelmsford, Essex; Nick James. Bottom left: The view from Epsom Downs, Surrey. January 10 at 17:07 UT, Canon Eos 300D, 300mm f/5 lens. Maurice Gavin. Bottom right: January 20, New South Wales, Australia. 3x30 sec., 85mm at f5.6. Gordon Garradd.

Notes and News

2006P1 (McNaught) - a Great Comet! (Jonathan Shanklin) ) / From the President (Richard Miles) / Solar Section (Lyn Smith) / A change of Director for the Saturn Section (Mike Foulkes) / The BAA Library and Archives (Richard Miles)

Photo: Comet McNaught over Bournemouth Pier, 2007 January 10 at 17:08 UT. (Jeremy Calderwood).

Refereed articles

Venus 2004: east and west elongations and solar transit ... Richard McKim, Keith Blaxall & Alan Heath

The year 2004 was exceptional in producing the first solar transit of Venus since the late Victorian era. The bright aureole and atmospheric ring were re-observed, and the entire phenomenon was witnessed for the first time ever in hydrogen alpha light. Although routine observations throughout 2004 were unexceptional, patterns of visibility of bright and dark markings, cusp extensions and cusp caps were recorded. No correlation was found between the latitude of the sub-Earth point and the visibility of either cusp cap, with the S. cap predominating for most of the year. It was possible to accurately follow individual ultraviolet dark markings over many consecutive rotations, extending from the E. to W. elongations, and thereby to make a current measurement of the synodic atmospheric rotation period for the near-equatorial features: 3.996 +/- 0.001 days. The true Ashen Light was reported visually on only a few occasions, but these correspond closely to times when infrared emission from the surface of the dark side was recorded in 1-micron waveband images. Some of the stable dark side albedo features were also visible upon the 1-micron images, and have been tentatively identified with known surface features. Infrared imaging at the same waveband showed little detail on the sunlit disk, but a few bright spots were sufficiently well observed to suggest a synodic rotation period close to 5.0 days, not atypical for the lower cloud decks.

Photo: Ultraviolet CCD images at the E. elongation 2004, by observers in Europe: J. Cooper (UK) with 178mm Mak-Newt., ATK-1HS and Schuler UV 365nm filter (top row, A-D); C. Pellier (France) with 355mm Schmidt-Cass., ATK-1HS and Schuler UV 365nm filter (bottom two rows, E-I)

The Iapetus magnitude puzzle ... Edward L. Ellis

Saturn's satellite Iapetus undergoes a wide range of brightness variations between magnitude 10.2 near western elongation and 11.9 near eastern elongation. However visual observers have frequently estimated the brightness of Iapetus to approach 9th magnitude at western elongation. This paper investigates the matter more fully and offers possible explanations for why visual observers overestimate the brightness of Iapetus.

Discovery of the real man behind the name of the lunar crater Kinau ... Robert A. Garfinkle & Bernd Pfeiffer

Detailed research by the authors has led them to correct the identity of the person named in the BAA's 1938 Memoir 'Who's Who in the Moon' as the eponym for the lunar crater Kinau, as being a German priest, teacher, and amateur astronomer Adolph Gottfried Kinau instead of the incorrectly listed C. A. Kinau.

Stag Lane (Edgware) Observatory and the 10-inch Dall-Kirkham-Dall Cassegrain telescope ... David Arditti

The author describes the construction and equipping of an urban observatory dedicated to lunar and planetary observation and imaging, including a description of the main telescope in use and its adaptation to the requirements of webcam imaging. Some of the techniques of planetary webcam imaging are also described.

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Observers' Forum

  • The other galaxies of Canes Venatici ... Stewart L. Moore
  • Daytime photometry of Comet McNaught ... Richard Miles

  • [Photo of M94 by Andrea Tasselli, Lincoln]

    BAA Update

  • Obituary: Edward L. Ellis (1931-2006) ... Richard McKim & Alan Heath
  • The 2006 Scottish Astronomy Weekend ... Dave Gavine

  • Meetings

  • Out of London Weekend, Liverpool, 2006 April 21-23 ... David Forshaw
  • Ordinary Meeting, 2006 May 31 ... Dominic Ford

  • Letters

  • Milan Štefánik and the rotation period of Venus: a centenary for 2007 ... Richard McKim
  • The non-emerging cosmos, and the 'false aurora' ... John C. Vetterlein
  • The Messier star clusters of Auriga ... Ron Livesey
  • Orbital dynamics at the MACE meeting ... Roger Dymock

  • More views of Comet 2006P1 (McNaught) ... Nick James, Martin Mobberley & Russell Cockman

  • Meetings Diary and notices

  • Sky notes for 2007 April & May ... Neil Bone

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