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Journal

No 54 - November 2007

Recent observations

Noctilucent cloud

There have been many nights with noctilucent clouds this season, but Scottish observers have not seen many due to the above average occurrence this year of more mundane tropospheric clouds. Nonetheless a few nights have been good enough, and Frank Howie took the 8 s, f/5, 200 ISO exposure shown on the front cover on the night 2007-07-08/09.

Perseids and other meteors

Dave Gavine at Joppa, on Aug 12/13 got 25 Perseids and 2 others between 22:30 and 00:10 UT, in a 4/8 cloud sky with limiting magnitude 4.5; then it clouded over completely. The best was a -4 mag in Lynx at 23:56. On Aug 13/14 it was clear 22:30-23:30, limiting magnitude 5.0. 15 Perseids and 1 sporadic.

Neil Grubb on the night 2007-08-22/23 caught a Kappa Cygnid in a 30 s exposure of the Milky Way in Cygnus.

Mike Dale under the dark skies of Arran one September night observed by chance several Alpha Aurigids.

Old Moon

Just a few days before Ramadan, Horst Meyerdierks has finally captured the old Moon on the morning of 2007-09-10. Only 1.6 % of the lunar disc were illuminated at that time. The exposure was 1/15 s at f/12.6 with 800 mm focal length. New Moon followed at 2007-09-11T12:44 UT (after 12:00 UT), and so Ramadan began in most countries at sunset on 2007-09-12, so that 2007-09-13 was Ramadan 1, 1428 AH (http://moonsighting.com). The Islamic calendar has years of 12 actual lunar phase cycles, about 354 days (http://en.wikipedia.org/wiki/Islamic_calendar).

old Moon C/2007 F1 LONEOS
Old Moon on 2007-09-10. C/2007 F1 LONEOS on 2007-10-22.8. f = 400 mm, f/6.3, Canon EOS 400D, 6 tracked exposures of 1 min each. The field is approx. 50'.

Comets

C/2007 F1 LONEOS was visible after sunset in mid October, moving from Coma into Bootes. Horst Meyerdierks measured these magnitudes, coma diameters and tail lengths from digital SLR images at f = 400 mm: 2007-10-14.8 UT, 7.0, 0.3', 0.8'; 2007-10-16.8, 6.7, 2', 4' (f = 135 mm); 2007-10-17.8, 6.3, 1.5', 3.5'; 2007-10-19.8, 5.9, 1.5', 5'; 2007-10-22.8, 5.8, 1.5', 25'; 2007-10-23.8, 6.3, 1', 2'.

17P/Holmes surprised professionals and amateurs alike with an outburst in brightness toward the end of October. The comet was near opposition at high declination in Perseus. It was brighter than δ Per, 500,000 times brigther than the predicted 17 mag. Although reports for 2007-10-24 had described it as a star-like object, Horst found it very bright and extended in 9x63 binoculars. He measured these magnitudes from digital SLR images at f = 50 mm: 2007-10-27.0 UT, 2.6; 2007-10-27.8, 2.5.

17P/Holmes
17P/Holmes on 2007-10-27.8 near the α Persei Group. The comet near the bottom left appears brighter than it is, due to the high contrast and its extended size. It is brighter than δ Per (centre bottom) but fainter than α Per (halfway from centre to top right). f = 50 mm, f/2.8, Canon EOS 400D, 20 s without tracking. The field is approx. 8°.

Contents

Cover page

ASE questionnaire

SAG magazine and online forum

Book review: Aurora

Observing group returns

Observing Mars in 2007/08

Recent observations

A new dark site for ASE

Forthcoming events

About the ASE Journal


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