Celestial Objects for Common TelescopesLongmans, Green, 1873 - 343 páginas |
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Página 1
... brightness . The original observations in the following pages * ' Aperture ' always means the clear space which receives the light of the object ; the diameter of the object - glass in achromatics , or the large speculum in reflectors ...
... brightness . The original observations in the following pages * ' Aperture ' always means the clear space which receives the light of the object ; the diameter of the object - glass in achromatics , or the large speculum in reflectors ...
Página 3
... brighter or fainter towards the centre , † or much better defined on one side of the focus than the other , the telescope * เ The real diameter of a star in the telescope would be inconceivably small . The apparent or ' spurious ' disc ...
... brighter or fainter towards the centre , † or much better defined on one side of the focus than the other , the telescope * เ The real diameter of a star in the telescope would be inconceivably small . The apparent or ' spurious ' disc ...
Página 6
... brightness of the object . Ordinary astronomical eye - pieces are shorter in proportion to their power . It is a better plan to change them by means of a short tube , or adapter , ' than by a screw ; in which case they are more liable ...
... brightness of the object . Ordinary astronomical eye - pieces are shorter in proportion to their power . It is a better plan to change them by means of a short tube , or adapter , ' than by a screw ; in which case they are more liable ...
Página 12
... brightness , it is better to leave it alone ; a slight loss of light is not so great an injury as would result from strong friction . The taking out or replacing of an object - glass or mirror is a delicate operation , and hurry or ...
... brightness , it is better to leave it alone ; a slight loss of light is not so great an injury as would result from strong friction . The taking out or replacing of an object - glass or mirror is a delicate operation , and hurry or ...
Página 14
... brightness of the object , the goodness of the telescope , and the steadiness of the air . Comets and nebulæ , generally speaking , will bear but little magnifying . For the moon and planets , the power should be high enough ( if the ...
... brightness of the object , the goodness of the telescope , and the steadiness of the air . Comets and nebulæ , generally speaking , will bear but little magnifying . For the moon and planets , the power should be high enough ( if the ...
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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.