Ordinary Meeting, 2007 November 24

 

Solar Section Update

Ms Smith reported that the Sun had been very inactive over the past few months. With the exception of a brief resurgence in May and June, sunspot counts had been declining throughout 2007, and were now very close to zero. In September, the Sun's face had gone for 22 days without showing any sunspots– from 6th to 27th – and although a few small sunspot groups had been seen in the following week, these had been followed by another draught, this time lasting for 29 days – from October 9 to November 5. The speaker pointed out that whilst these spotless spells were long, they were far from being record-breakers; in 1913, for example, the Sun had gone for 92 days without showing any sunspots.

This period of quiescence had not been entirely unexpected, and it could be simply explained: sunspot cycle 23 had now ended and the new cycle had not yet begun. The first sunspots of cycle 24 might appear at any time, although the latest predictions from NASA were that they would not appear until 2008 March.

The speaker went on to report that whilst the Sun's face had little to show in white light at present, it remained active when viewed through Hα or Calcium K-line filters. Even at this time of solar minimum, observers using such filters were reporting several prominences on the solar limb each month.

The speaker closed by reporting that the section was developing a computerised observation filing system which would allow its members to report sunspot counts electronically via the BAA website. The section had been actively liasing with the preceding speaker to learn from the SIDC's experiences of setting up such systems. She then handed over to the section's Assistant Director, Mr Tony Broxton.

Mr Broxton reported that he was currently working on a complete rewrite of the Solar Section Observers' Handbook. He explained that his aim was to develop it into a manual which could be readily understood, even by readers who came to it with very little previous experience. The new version would start at a basic level and contain minimal mathematical content, yet it would work right through to a point where the reader could make scientifically useful observations and return them to the section. A publication date in early 2008 was planned, and its release would be advertised in magazines and at astronomy fairs with the hope of its reaching those who might previously have been rather daunted at the idea of joining the BAA.

Following the applause for Ms Smith's and Mr Broxton's reports, the President introduced the afternoon's final speaker, Mr Jonathan Shanklin, to present a brief report on the appearance of Comet McNaught.

Ashburn

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39.04°N
77.49°W
EDT

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