Ordinary Meeting, 2002 March 16


Sky Notes

Mr. Mobberley opened by looking at GK Per, the remnant of a supernova explosion discovered by Revd Anderson on 1901 February 21 – the first supernova discovery of the 20th century. Since 1966 this remnant has behaved as a dwarf nova type cataclysmic variable, rising from mag 13 to mag 10 every few years. Since early 2002 March such brightening had been observed, and Hazel McGee reported an estimate of mag 10.5 for 2002 March 15.

The speaker reported that the next planetary occultation would be that of Saturn on April 16, which would be at the sociable hour of 2100-2128. The Moon would not be full for this occultation as had been the case in other recent events. There would also be a daylight occultation on May 14 which it would probably not be possible to observe.

Moving onto supernovae discoveries, the speaker gave tribute to Mark Armstrong's work. In the week preceding the meeting, Mr. Armstrong had discovered 2002bl, 2002bn and 2002br – all of which were very subtle on their discovery plates. The speaker was stunned that since 1995 June, Mr. Armstrong had reported observations on 871 nights, amassing a total of 194,610 images. The speaker showed a light curve for 2002ap, making particular reference to a recent observation which suggested it to be flattening out. The President called for observations to confirm this. Moving onto Jupiter, the speaker was pleased to announce Damian Peach's presence at the meeting, and invited him to talk about his superb planetary images.

Mr. Peach first showed his superb image of Jupiter from 2002 February 15, highlighting the passage of the anticyclonic storm BA past the Great Red Spot. Some had anticipated this would be a dramatic event, but in the event BA passed the GRS with no effect other than a few streaks ahead of it. Mr. Peach also showed an image of Saturn from February 15 and commented that the planet was visible through the Cassini divide. Mars was now very small, but high in the sky. Mr Peach reported that the dust storm that had been observed at last summer's opposition had now subsided, and surface details could be resolved. He also displayed a superb image of the Jovian moon Ganymede with surface features including Nicholson resolved.

Mr. Mobberley thanked Mr. Peach for showing his impressive images before discussing the comet scene. Ikeya-Zhang was now an impressive object, two days off perihelion, and the speaker reported seeing some superb images from both Schmidt cameras and telephoto lenses. The ion tail was undoubtedly the best since Hale-Bopp. Maurice Gavin reported spectral observation of three emission lines in the blue/green, suggesting the comet was doing something rather more interesting than just reflecting sunlight. The speaker reported that although the comet will fade after perihelion, it will become 2.5 times closer to Earth in April, and so will continue to give an impressive show for some time yet. He anticipated it would feature in the dawn sky peaking at 62° declination. Finally before closing, the speaker called for observation of 2002WM-Linear which peaked at mag 3 in the southern hemisphere and was expected to remain at mag 7 in the north.

Following much applause for Mr Mobberley's talk, the President welcomed Mr. Owen Brazell, editor of The Deep Sky Observer, to review the British deep sky scene.




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