Название: Choosing and Using a Refracting Telescope
(Patrick Moore's Practical Astronomy Series)
Автор: PatrickMoor
Издательство: Springer
Год: 2010
Страниц 284
ISBN:1441964029
Формат: PDF
Размер:16,3 MB
Язык Английский
Choosing and Using a
Refracting Telescope has been written for the many amateur astronomers who
already own, or are intending to purchase, a refracting telescope – perhaps to
complement their existing arsenal of larger reflecting telescopes – or for the
specialist who requires a particular refractor for serious astronomical
applications or nature studies.
Four hundred year ago, during the winter of 1609, a relatively unknown Italian
scientist, Galileo Galilei designed a spyglass with two crude lenses and turned
it skyward. Since then, refractors have retained their dominance over all types
of reflector in studies of the Moon, planets and double stars because of the
precision of their optics and lack of a central obstruction in the optical
path, which causes diffraction effects in all commercially-made reflectors.
Most mature amateur astronomers got started with a 60mm refractor, or something
similar. Thirty years ago, there was little choice available to the hobbyist,
but in the last decade long focus crown-flint achromats have moved aside for
some exquisitely crafted apochromatic designs offered by leading commercial
manufacturers. There has been a huge increase in the popularity of these
telescopes in the last few years, led by a significant increase in the number
of companies (particularly, William Optics, Orion USA, StellarVue, SkyWatcher and
AstroTech) who are now heavily marketing refractors in the amateur astronomical
magazines.