Aurora

The uniquely beautiful light display of an aurora is the result of charged particles colliding with tenuous atmospheric oxygen and nitrogen, more than 60 miles above the Earth, when the magnetosphere is disturbed by changes in the solar wind.

Often - and incorrectly - regarded as being confined to high northern and southern latitudes, major auroral displays are visible from even the southern USA and the south of England, and occur perhaps twenty times in each eleven-year sunspot cycle.

Major auroral storms always cause great interest and excitement in the media, and of course provide practical astronomers with the opportunity to study and image them.

This book describes the aurora from the amateur observational viewpoint, discusses professional studies of auroral and geomagnetic phenomena to put amateur work in context, and explains how practical observers can go about observing and recording auroral displays.

Auteur

Neil Bone is the author of Deep Sky Observer's Guide, Philip's/Firefly (2004); Mars Observer's Guide, Philip's/Firefly (2003); Guide to the Constellations, Astronomy Now/Polestar (2002); Observing Meteors, Comets, Supernovae and other Transient Phenomena, Springer (1998); Observer's Handbook: Meteors Philip's/Sky (1993); The Aurora: Sun-Earth Interactions, Ellis Horwood (1991), Second Edition Wiley/Praxis (1996), as well as numerous articles and papers.

Résumé

For the majority of amateur astronomers, who live at the latitudes of North America, the British Isles and Australia, the aurora is a relatively infrequent visitor to the night sky. Major displays visible to the southern United States or the south of England occur perhaps 20 times in each 11-year sunspot cycle. When they occur, such auroral storms are a source of great interest and excitement.

A number of books highlighting the impact of auroral/geomagnetic storms on communications and satellite technology have appeared in recent years . None, however, has addressed the observational angle. This new book addresses a gap in the literature, offering an explanation of the aurora's causes, how the occurrence of major events may now be predicted, and how amateur observers can go about recording displays.

Observation of the more frequent displays seen at higher latitudes (the northern US, Canada, and Scotland, for example) are also covered in detail. Visual and photographic (chemical and digital) observations are most usual, but magnetic and radio recording of auroral effects is possible too.

While the principal aim of the book is to describe the aurora from the amateur observational viewpoint, it discusses professional studies of auroral/geomagnetic phenomena, to put amateur work in context.

A glossary gives concise explanations of necessary technical terms, and there is also a short bibliography.

Contenu
Atmospheric Phenomena.- Causes of the Aurora.- Auroral Forecasting.- Observing the Aurora.- Historical Aurorae and More Recent Events.- Aurora Elsewhere.- Early observers and theorists of the aurora classed it along with other atmospheric phenomena as a meteor. In common with many of his other ideas that remained unchallenged until well into the sixteenth century, Aristotle's fourth century BC view of these events being the result of ignition of rising vapors belowthe innermost celestial sphere prevailed for some time. An alternative, proposed by the Roman philosopher Seneca in his Questiones Naturales, was that aurorae were flames viewed through chasmatacracks in the heavenly firmament..- Noctilucent Clouds and other Phenomena.