The Stars: A Study of the Universe

actual Algol apical motion appear astronomers average Beta Lyræ binary systems body bright lines brighter stars brightest brilliancy catalogue celestial sphere centre century chapter cluster colour components conclusion constellation dark lines density determined direction distance double stars earth eclipses emitted equal Eta Aquila fact faint fainter follows galaxy give greater Harvard Observatory heavens Herschel hydrogen hydrogen lines increase Kapteyn latter less LICK OBSERVATORY limit lucid stars mass measured Milky naked eye nearly nebula number of stars observations Observatory orbit Orion parallactic motion parallax period photographic Pickering planet plates position proper motion question R. A. Dec radial motion radius ratio remarkable revolving round right ascension seems seen Sirius sixth magnitude solar apex solar motion space spectra spectroscope spectroscopic binary spectrum square degrees star-density stellar supposed surface telescope temperature tion tude variable stars variation velocity visible wave-length zone