The Practical AstronomerSeeley, Burnside, and Seeley, 1845 - 567 pages |
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Page xii
... inches diameter SECT . 6. - THE ACHROMATIC TELESCOPE . page 232-235 . Imperfections of common refracting telescopes - Dollond's discovery— Newton's error- Explanation of the principle of achromatic teles- copes -Combination of lenses ...
... inches diameter SECT . 6. - THE ACHROMATIC TELESCOPE . page 232-235 . Imperfections of common refracting telescopes - Dollond's discovery— Newton's error- Explanation of the principle of achromatic teles- copes -Combination of lenses ...
Page 19
... inch square , and attached to one of the finest harpsicord wires , about ten inches long , and nicely balanced at ... diameter , which , passing through the front glass of the box , were collected into the focus of the mirror upon the ...
... inch square , and attached to one of the finest harpsicord wires , about ten inches long , and nicely balanced at ... diameter , which , passing through the front glass of the box , were collected into the focus of the mirror upon the ...
Page 64
... diameter is two inches or forty inches ; or in other words , were the portion of the sphere on which it is ground formed into a globe of corresponding con- vexity , it would be four inches or eighty inches 64 THE PRACTICAL ASTRONOMER .
... diameter is two inches or forty inches ; or in other words , were the portion of the sphere on which it is ground formed into a globe of corresponding con- vexity , it would be four inches or eighty inches 64 THE PRACTICAL ASTRONOMER .
Page 65
Thomas Dick. vexity , it would be four inches or eighty inches in diameter . figure 5 . Plano - convex . Plano - concave . Double Convex . Double Concave . JKOX CO B C A E F Meniscus . Concavo - convex . The axis of a lens is a straight ...
Thomas Dick. vexity , it would be four inches or eighty inches in diameter . figure 5 . Plano - convex . Plano - concave . Double Convex . Double Concave . JKOX CO B C A E F Meniscus . Concavo - convex . The axis of a lens is a straight ...
Page 68
... inches , -— in the latter case it will be thirteen , fifteen , or sixteen inches , according to the distance of the ... diameter of the sphere of which it is a 68 THE PRACTICAL ASTRONOMER .
... inches , -— in the latter case it will be thirteen , fifteen , or sixteen inches , according to the distance of the ... diameter of the sphere of which it is a 68 THE PRACTICAL ASTRONOMER .
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Common terms and phrases
achromatic telescope adjusted altitude angle apparent magnitude appear astronomical atmosphere axis beautiful brass Camera Obscura candle celestial centre circle colours concave lens concave mirror construction converging convex lens crown glass dark degree direction distant objects distinctly Ditto Dollond double double stars earth effect equal equatorial exhibited experiments eye-glass eye-piece feet focal field of view figure fixed flint glass fluid focal length Gregorian half heavens hole horizon inches aperture inches diameter inches focal distance instrument invention Jupiter lenses likewise magnifying power magnitude meridian metal minute moon motion nature nearly Newtonian telescope object-glass observations observatory optical opticians parallel rays pass perceived piece placed planets polished position prism produced proportion radius rays of light reflecting telescopes reflector refraction represented Right Ascension satellites Saturn screw seen side single lens solar space specula speculum stars supposed surface tance teles tion tube Venus violet visible
Popular passages
Page 156 - As the appearance of the bow that is in the cloud in the day of rain, so was the appearance of the brightness round about. This was the appearance of the likeness of the glory of the Lord.
Page 157 - And it shall come to pass, when I bring a cloud over the earth, that the bow shall be seen in the cloud: 15 and I will remember my covenant, which is between me and you and every living creature of all flesh; and the waters shall no more become a flood to destroy all flesh.
Page 180 - Besides, the Jews and other ancient nations as well as modern Europeans have adopted the division of the week into seven days, and have named them from the seven planets : now if we increase the number of the planets this whole system falls to the ground.
Page 5 - Eternal coeternal beam May I express thee unblam'd ? since God is light, And never but in unapproached light Dwelt from eternitie, dwelt then in thee, Bright effluence of bright essence increate ! Or hear'st thou rather pure Ethereal stream, Whose fountain who shall tell? Before the sun, Before the Heavens, thou wert, and at the voice Of God, as with a mantle, didst invest...
Page 178 - Oh, my dear Kepler," says Galileo, " how I wish that we could have one hearty laugh together. Here, at Padua, is the principal professor of philosophy, whom I have repeatedly and urgently requested to look at the moon and planets through my glass, which he pertinaciously refuses to do.
Page 107 - ... numberless series of pilasters, arches, castles well delineated, regular columns, lofty towers, superb palaces, with balconies and windows, extended alleys of trees, delightful plains with herds and flocks, armies of men on foot and horseback, and many other strange figures in their natural colors and proper actions, passing rapidly in succession along the surface of the sea, during the whole of the short period of time while the above-mentioned causes remain.
Page 179 - There are seven windows given to animals in the domicile of the head, through which the air is admitted to the tabernacle of the body, to enlighten, to warm, and to nourish it. What are these parts of the microcosmos? Two nostrils, two eyes, two ears, and a mouth.
Page 179 - There are seven windows in the head: two nostrils, two eyes, two ears, and a mouth; so in the heavens there are two favorable stars, two unpropitious, two luminaries, and Mercury alone undecided and indifferent. From which and many other similar phenomena of nature, such as the seven metals, etc., which it were tedious to enumerate, we gather that the number of planets is necessarily seven.
Page 156 - Look upon the rainbow, and praise him that made it; very beautiful it is in the brightness thereof. It compasseth the heaven about with a glorious circle, and the hands of the most High have bended it.
Page 286 - Amidst these thoughts I was forced from Cambridge by the intervening plague, and it was more than two years before I proceeded further.