Elements of astronomy by Gilbert ValeElements of astronomy by Gilbert Vale

Elements of astronomy

byGilbert Vale

Paperback | February 9, 2012

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1846 Excerpt: ... LESSON TWENTY FOURTH. Which of the celestial objects are the most numerous? The fixed stars. Why are they called fixed stars? Because they do not materially change their position in respect to each other. Have they any motion? They appear to have a motion of about one degree and ten minutes, in one hundred years. What is this motion called? The precession of the equinoxes. Why is it called the precession of the equinoxes? In describing the whole circle of the ecliptic, the sun falls short of the same star from which he set out the year before, about 50" of a degree; so that with respect to the fixed stars, the sun and equinoctial points fall back as it were 1 in about seventy years; this precession amounts to one whole sign in two thousand, one hundred, and forty years. What do you understand by a degree? The sixtieth part of a circle. What do you understand by a minute? In time it is the sixtieth part of an hour, in motion the sixtieth part of a degree. How are the stars distinguished from the planets? By their scinfiliations or twinkling. The Planets shine steadily, and on a clear night they may easily be distinguished. How are stars divided by astronomers 1 Into orders, according to their apparent sizes. What are the largest called 1 Stars of the first magnitude; the second in size, stars of the second magnitude, and so on to the sixth. What are those called which cannot be seen without the aid of the telescope? Telescopic stars. Into how many classes are these divided? Ten: making in the whole sixteen magnitudes. What is said of the milky way 1 That it undoubtedly consists of many hundreds of thousands of stars. Some parts of it present the appearance of whitish spots, which are permanent and in which no distinct stars are visible. What are these spots ...
Title:Elements of astronomyFormat:PaperbackDimensions:18 pages, 9.69 × 7.44 × 0.04 inPublished:February 9, 2012Publisher:General Books LLCLanguage:English

The following ISBNs are associated with this title:

ISBN - 10:0217713580

ISBN - 13:9780217713580