Celestial Objects for Common TelescopesLongmans, Green, 1873 - 343 páginas |
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Página 3
... dark field ; a slight dis- placement of the focus either way should enlarge the disc into a luminous circle . If ... darkness out of the focus , which should be nearly the same on either side of it . may be serviceable , but is not of ...
... dark field ; a slight dis- placement of the focus either way should enlarge the disc into a luminous circle . If ... darkness out of the focus , which should be nearly the same on either side of it . may be serviceable , but is not of ...
Página 4
... darkness . This ' outstanding ' or uncorrected colour results from the want of a perfect balance between the optical ... dark sky . A red or yellow border would be bad ; but before condemning an instrument from such a cause , several eye ...
... darkness . This ' outstanding ' or uncorrected colour results from the want of a perfect balance between the optical ... dark sky . A red or yellow border would be bad ; but before condemning an instrument from such a cause , several eye ...
Página 17
... dark , if you wish it to do its best . * 10. When a very minute star or faint nebula is not to be seen at once , do ... darkness for a quarter of an hour . C observer , not to lose sight of the immediate relation THE MODE OF OBSERVATION . 17.
... dark , if you wish it to do its best . * 10. When a very minute star or faint nebula is not to be seen at once , do ... darkness for a quarter of an hour . C observer , not to lose sight of the immediate relation THE MODE OF OBSERVATION . 17.
Página 19
... dark glass of the solar cap which is to be screwed on the eye - piece ; red is often used , and may be dark enough — it is not so always — but it trans- mits too much heat ; green is cooler , but seldom sufficiently thick . The Germans ...
... dark glass of the solar cap which is to be screwed on the eye - piece ; red is often used , and may be dark enough — it is not so always — but it trans- mits too much heat ; green is cooler , but seldom sufficiently thick . The Germans ...
Página 20
... 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 , however , is free ...
... 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 , however , is free ...
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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.