Celestial Objects for Common TelescopesLongmans, Green, 1873 - 343 páginas |
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Página 11
... surface may be almost always avoided . The object - glass or speculum , if kept in a cold place , should not be uncovered , if possible , in a warmer air till it has gained something of its temperature ; and it must be invariably closed ...
... surface may be almost always avoided . The object - glass or speculum , if kept in a cold place , should not be uncovered , if possible , in a warmer air till it has gained something of its temperature ; and it must be invariably closed ...
Página 12
... surface first with a soft camel's hair pencil or varnishing brush , which will remove loose particles ; then use , very cautiously , a very soft and even piece of chamois leather , which has not been em- ployed for any other purpose ...
... surface first with a soft camel's hair pencil or varnishing brush , which will remove loose particles ; then use , very cautiously , a very soft and even piece of chamois leather , which has not been em- ployed for any other purpose ...
Página 13
... surface held at a safe height over it will speedily be cleared of moisture . Eye - piece lenses require occasional wiping ; the leather may be pressed to their edges with a bit of soft wood . Their flat faces are easily scratched if ...
... surface held at a safe height over it will speedily be cleared of moisture . Eye - piece lenses require occasional wiping ; the leather may be pressed to their edges with a bit of soft wood . Their flat faces are easily scratched if ...
Página 19
... surface , the rapid and extensive disturbances of which it is the scene , as well as the daily visibility of the object , all combine to invite research . But the student had better not begin here : more than one astronomer has suffered ...
... surface , the rapid and extensive disturbances of which it is the scene , as well as the daily visibility of the object , all combine to invite research . But the student had better not begin here : more than one astronomer has suffered ...
Página 20
... surfaces , that a dark glass , the tint of which is of course better dispensed with , becomes unnecessary : and the same end is attained in a very ingenious double - prism eye - piece devised by Prof. Pickering : neither apparatus ...
... surfaces , that a dark glass , the tint of which is of course better dispensed with , becomes unnecessary : and the same end is attained in a very ingenious double - prism eye - piece devised by Prof. Pickering : neither apparatus ...
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Términos y frases comunes
achr achromatic aperture Aquil astronomers atmosphere beautiful Binary bluish Boöt bright brighter brilliant Buffham Cassini centre Ceph Clusters colour comet constellation craters curious dark Dawes deep diameter disc Double Stars Drac dusky Earth eye-piece faint field flushed white globe greenish grey Herc Herschel Huggins interior Jupiter larger Lassell libration light lilac limb luminous lunar minute stars Moon motion naked eye nearly nebulæ noticed nucleus object object-glass observers orange pair pale blue pale white pale yellow photosphere Pisc planet proper motion Red Star reflector region remarkable Right Ascension ring ruddy satellites Schm Schr Schröter Schwabe Secchi seen shadow shew side silvery white smaller smalt solar sometimes spec spots streaks surface Taur telescope topaz Triple Virg visible xIxh xvih XVIII yellowish
Pasajes populares
Página 345 - A NEW STAR ATLAS, for the Library, the School, and the Observatory, in Twelve Circular Maps (with Two Index Plates). Intended as a Companion to ' Webb's Celestial Objects for Common Telescopes.
Página 46 - Fairest of stars, last in the train of night, If better thou belong not to the dawn, Sure pledge of day, that crown'st the smiling morn With thy bright circlet, praise Him in thy sphere, While day arises, that sweet hour of prime.
Página 182 - Lift up your eyes on high, and behold who hath created these things, that bringeth out their host by number; he calleth them all by names by the greatness of his might, for that he is strong in power; not one faileth.
Página 345 - Why didn't somebody teach me the constellations, too, and make me at home in the starry heavens which are always overhead, and which I don't half know to this day?
Página 30 - I have said, he spent to satisfy himself; six more years to satisfy, and still thirteen more to convince, mankind. For thirty years never has the Sun exhibited his disc above the horizon of Dessau without being confronted by Schwabe's imperturbable telescope, and that appears to have happened, on an average, about 300 days a year.
Página 65 - Webb makes the following remarks on the rills:—"These most singular furrows pass chiefly through levels, intersect craters (proving a more recent date), reappear beyond obstructing mountains, as though carried through by a tunnel, and commence and terminate with little reference to any conspicuous feature of the neighbourhood.