Modern Astronomy, Its Rise and Progress

according actually announced appear asteroids astronomer atmosphere attention believed binary bodies bright called catalogue century close clouds clusters comets conclusion confirmed considerable dark detected determination diameter direction disc discovered discovery distance doubt early Earth evidence existence explanation extensive fact faint four further galactic giant greater groups Herschel hypothesis idea important indicated Jupiter known later less light lines Lowell lunar magnitude Mars mass matter means measured meteors method miles million Moon motion Mount Wilson nature nebulae Nova objects observations Observatory orbit origin period photographic Pickering planet planetary position possible present probably problem Professor prominences recent regarded regions remarked result ring rotation round satellites seems seen Shapley showed Solar System space spectra spectroscopic spectrum spirals stars stellar suggested surface telescope temperature theory tion universe variable visible