History of Astronomy |
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Page 127
These appearances may be partly due to a proper motion; but, so far as it went,
this was a beautiful confirmation of Wilson's discovery. Howlett, however, in 1894,
after thirty years of work, showed that the spots are not always depressions, ...
These appearances may be partly due to a proper motion; but, so far as it went,
this was a beautiful confirmation of Wilson's discovery. Howlett, however, in 1894,
after thirty years of work, showed that the spots are not always depressions, ...
Page 151
When a photograph is taken of a region of the heavens including an asteroid, the
stars are photographed as points because the telescope is made to follow their
motion; but the asteroids, by their proper motion, appear as short lines.
When a photograph is taken of a region of the heavens including an asteroid, the
stars are photographed as points because the telescope is made to follow their
motion; but the asteroids, by their proper motion, appear as short lines.
Page 162
made astronomers quite ready to waive the claim for a rigid proof of the earth's
motion by measurement of an annual parallax of stars, which they ... Both used
stars whose proper motion had been found to be large, as this argued proximity.
made astronomers quite ready to waive the claim for a rigid proof of the earth's
motion by measurement of an annual parallax of stars, which they ... Both used
stars whose proper motion had been found to be large, as this argued proximity.
Page 163
The proper motions and parallaxes combined tell us the velocity of the motion of
these stars across the line of sight: a Centauri 14.4 miles a second = 4.2
astronomical units a year; 6.1 Cygni 37.9 miles a second = 1 1.2 astronomical
units a ...
The proper motions and parallaxes combined tell us the velocity of the motion of
these stars across the line of sight: a Centauri 14.4 miles a second = 4.2
astronomical units a year; 6.1 Cygni 37.9 miles a second = 1 1.2 astronomical
units a ...
Page 164
the proper motions of Arcturus and Sirius. In 1738 J. Cassini' showed that the
former had moved five minutes of arc since Tycho Brahe fixed its position. In
1792 Piazzi noted the motion of 61 Cygni as given above. For a long time the
greatest ...
the proper motions of Arcturus and Sirius. In 1738 J. Cassini' showed that the
former had moved five minutes of arc since Tycho Brahe fixed its position. In
1792 Piazzi noted the motion of 61 Cygni as given above. For a long time the
greatest ...
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accurate Airy ancient Astronomer Royal astronomical units bright calculations Cape catalogue centre century Chaldaeans Chinese comet Copernicus diameter discovered discovery earth Egyptian epicycles equatorial error excentric explain fact fixed stars Galileo Greenwich Halley heavenly bodies heavens heliometer Hipparchus History of Astronomy Huggins instruments JOHANNEs KEPLER John Herschel Jupiter Jupiter's Kepler Laplace Lick Observatory light line of apses line of sight lunar Mars mathematical mean distance measured ment Mercury meteor miles a second moon nebulae Newton º º observations Observatory orbit parallax period photographic physical planet planetary pole position predicted proper motion proved Ptolemy R. S. Phil records refractor retrograde retrograde motion revolving round ring rotation satellites Saturn seems showing Sir William Herschel Sirius solar eclipse solar system spectra spectroscope spectrum sphere spots stellar sun-spot supposed tables telescope theory tion Trans Tycho Brahe universal gravitation Uranus velocity Venus Verrier
Popular passages
Page 67 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
Page 26 - So he sate and cunningly guided the craft with the helm, nor did sleep fall upon his eyelids, as he viewed the Pleiads and Bootes, that setteth late, and the Bear, which they likewise call the Wain, which turneth ever in one place, and keepeth watch upon Orion, and alone hath no part, in the baths of Ocean. This star, Calypso, the fair goddess, bade him to keep ever on the left as he traversed the deep.
Page 53 - The third, viz. that the squares of the periodic times are proportional to the cubes of the mean distances...
Page 79 - Wherefore if according to what we have already said it should return again about the year 1758, candid posterity will not refuse to acknowledge that this was first discovered by an Englishman.
Page 122 - ... They have not been regarded as so successful as his geometrical analysis of the observed phenomena. It is only just to add that he himself did not attach equal weight to them ; for in answer to objections urged by Lalande to his theory that the spots are depressions, Wilson wrote thus in 1783 : — ' Whether their first production and subsequent numberless changes depend upon the eructation of elastic vapours from below, or upon eddies or whirlpools commencing at the surface, or upon the dissolving...
Page 51 - He then said boldly that it was impossible that so good an observer as Tycho could be wrong by eight minutes* and added, " out of these eight minutes we will construct a new theory that will explain the motions of all the planets.
Bibliographic information
| Title | History of Astronomy Hist. of sci. series History of the sciences |
| Author | George Forbes |
| Publisher | Putnam, 1909 |
| Original from | the University of California |
| Digitized | 29 Nov 2007 |
| Length | 200 pages |
| Export Citation | BiBTeX EndNote RefMan |