MONSTER TELESCOPE ON WANDSWORTH COMMON.

New Zealander, Volume 9, Issue 777, 24 September 1853, Page 4

MONSTER TELESCOPE ON WANDSWORTH COMMON.

Astronomical science has been much advanced lately by the Rev. Mr, Craig, Vicar of J.eaminirton, who, at Ins own cost, has erected on Wandsworth Common an astronomatic telescope, the largest in the world,and from *rbicb the most important results may be anticipated. U he -fcuildmg was commenced lour months since, and consists of a plain central tower of brick, the walla of which are about 18 inches thick, 64 feet high, and 15 feet in diameter. It is erected upon a solid bed of concrete, and weighs 220 tons. The tower ia constructed so as to prevent vibration. By the side of the tower hangs the Jelescope, the tube of which is shaped like a

cigar,andis 85 feet long. At one end is the eye piece, five feet from the ground, and at the other'the dew cap, the object of which is to prevent the absorbtion of moisture which occurs during the night. The exterior is of bright metal, and the interior painted black to absorb the diverging rays of light. The instrument has a focal distance varying from 76 to 85 feet, and its greatest circumference is 13 feet, and the widest, portion of the tube being 24 feet from the object glass; and this particular point was the result of careful experiment. The great essential of so large an instrument is that there should be no vibration, and Mr. W. Gravatt, F.R. S., the engineer, has so adjusted the instrument to the tower that the vibration at one end neutralizes that of the other. The lower end of the tube is supported on a wooden frame work, to which wheels are attached, and those wheels traverse a circular iron railway 52 feet from the base of the tower. The other depends from an iron chain, which can sustain a weight of 15 tons, from the top of the tower, and this chain, which passes over ptillies through the top to the other side, can be elevated or depressed by a windlass, so as to raise or lower the tube from azimuth to an anglo of SO degrees of elevation as easily as an ordinary telescope, and with greater certainty as to the result. The slightest pressure applied to the works resting on the railway, causes the tube to revolve so that the opposite sides of the horizon may be viewed in a few minutes. Close to the observer's hand are two small wheels, one of which raises or lowers while the other moves it from side to side, within a space of three feet, sufficient for all ordinary purposes. The instrument has an object glass of two feet aperture, and is of marvellous power, is novel in its details and construction, and has been named, by the visitors who have tested it, the Craig telescope, a compliment due to the ingenious inventor, and who has followed the Cambridge precedent where the refracting telescope has been called after the Duke of Northumberland. This is the only telescope ever constructed of English material-', and proves what British skill can achieve, as well as the equality of English materials and the capability of English engineers and mathematicians. The lenses were made at Chance's, near Birmingham, and are free from stria? or bubbles,—one of flint, the other of pla'e, glass; the two placed in tion and constitute the astronomatic glass. The optical arrangements were carried out by Mr. Slater, Somer'splace West. Euston-square. The tube when mounted weighs near four tons. As a measuring instrument, or for penetrating space, it exceeds all others. It separates points of light so minutely that it must be valuable as a discovering telescope. It resolves the milky way not only into brilliant star-dust, but subdivides it into regular constellations, showing counter parts of the Orion, (lie Great Bear, and other brilliant galaxies of our systom adorned with gorgeous colours. The lenses are so astronomatic that Saturn appears of milk-like whiteness, and the interest in this planet has been increased in consequence of the assertion of the astronomer Bona, of the Cambridge Observatory, that he saw a third belt around it. Lord Ross's telescope was used in vain to solve this doubt, but this third belt, of a clear gray colour, is distinctly aeen through the Craig telescope. Some idea of its power may be formed from the fact that the light of the moon is magnified 40,000 times, and in such objects as the lunal mountains the whole of these rays may be allowed to pass to the focal point, as they do not confine it to any appreciable degree. The moon seen through this telescope is a most magnificent object, the whole of its mountain rays being seen with distinctness, and it is said that if there was an object of the size of Westminster Abbey in the moon it could be distinctly revealed. Soon after its erection its open penetrating powers were directed to a minuto speck of light on one of the constellations, which is very seldom seen by the best instruments; the Craig telescope discovered it was not n speck of light but a double star. Mr. Craig intends to asertain, as soon as the instrument is fully ad justed,whether the planet Venus has a satellite or not. This discovery would be a great advantage to science. It has been found that the instrument is yet deficient in one of the lenses, it being the five-thousandth part of an inch too flat. The advantages which this wonderful instrument will confer upon astronomical science, when fully perfected in its various details, are incalculable.