The Wanganui Astronomical Observatory.

New Zealand Graphic, Volume XXXI, Issue II, 11 July 1903, Page 100

The Wanganui Astronomical Observatory.

The illustrations on these pages will give our readers a general idea of the tine astronomical observatory lately erected in Wanganui, as well as of the large refracting telescope placed in position there. The formation of this society, due to the efforts of a few enthusiasts in astronomy. dates from the evening of July 12. I'JOI. A series of lectures were being given in the Museum Hall during the winter months, the course beginning with one on “Astronomy’’ by Prof. Maciaurin, of Victoria University, Wellington. Mr J. T. Ward, the prime mover in this enterprise, requested the Professor to ask all interested in the formation of an Astronomical Society to remain after the lecture, to which a few acceded. A short discussion resulted in a meeting being fixed for the following week, to take place in the Technical School. Circulars were sent out to all likely supporters, with the result that at the following meeting about sixty ladies and gentlemen pledged themselves to support the project. The Society was formally inaugurated bv the election of officers and committee. consisting of president and hon. director. Mr J. T. Ward; vice-presi-dents. Mr Jas. Watt. Mr H. J. Jones, Mr Henry Peake; hon. treasurer. Mr O. A. Harvey; hon. secretary, Mr W. IL MeCaul; committee, Messrs. H. T. Johns. D. Hutton. S. Austin. C. R. Cooke. J. K. Manning. A. A. Elliott, J. (1. Moon. Morton Jones. It being the conviction of the founder of this Society that a telescope of fair power, and an observatory, would be the surest means of drawing all interested in the Society to a focus, inquiries were at once made of several leading telescope makers in the United Kingdom as to price of instruments, the outcome of which was the offer of the very tine telescope now erected, the description of which is as follows: —Refracting. or direct vision, telescope of 9A inches diameter and 12 feet focus, with Finder 21 inches diameter; battery of eye-pieces magnifying from 32 to 750 diameters; Filar and Position Micrometer with divided heads on silver, position circle on silver, reading by opposite verniers, battery of 10 eye pieces from 100 to 1175; Cooke’s two movement adapter for centreing object; solar and stellar diagonal eye-piece; Dawes’ eye-piece (for observing the sun) ; aluminium shutter to object glass. AH the above, as well as the circles to equatorial. by T. Cooke and Sons, of York, England. The telescope is mounted on what is known as the “English” form of equatorial. as designed by J. Fletcher, Esq., of Tarnbank Observatory, Cumberland, England, and described in the monthly notices of the Roval Astronomical Soci-

ety, Vol. 25, page 241. In this form of mounting the telescope is supported on a massive axis, weighing nearly two tons, which rests at one end on a large iron bracket, which is fastened to a cast-iron column, 12ft. high, of architectural proportions, the lower support for the axis is an adjustable stepping-piece of brass resting in iron bearings, and moved by set screws in azimuth. The great axis, as shown in

illustration, has a cubed centre of 17 inches diameter, pierced to carry the declination axis. It may be mentioned for the benefit of those unacquainted with this form of mounting that the large polar axis when in adjustment points to the poles of the heavens, or is parallel with the earth’s axis. The declination axis being at right angles to this will, of course, point to the celestial equator. A telescope mounted in

th s manner can be pointed to a star, or other celestial body, by means of divided circles attached to these parts. In the instrument before us these circles are 42 inches in diameter, divided finely on silver, and reading to single seconds of both right ascension (East and West)," and declination (North and South), and by these means, when the

instrument is in correct adjustment, objects invisible to the eye may be “picked up’’ in the field of telescope. As all celestial bodies appear to move from east to west through the rotation of the earth on its own axis from west to east, it follows -as a matter of course that when the instrument is pointed on a star we must keep it moving if we do not wish to lose sight of it. To overcome this difficulty a powerful driving elock is attached to the edge of the circle. at lower end of the large axis, which is kept in motion by a weight attached to a steel eord, and working on the clock at a pressure of 22Albs. In this way an object may be placed in the centre of the field of telescope, and retained there for the purposes of photography, or drawing, or measurement. The sight ascension circle is a movable one, which can be set to sidereal (star) time, and the clock started; it wiil then continue to keep time, while the telescope can be set on any object and clamped on to the circle, when it imediately partakes of the motion, and follows the object in its movement across the sky. The Observatory, which is erected on a site granted to the Society by the Borough Council, stands fairly high, and overlooks the town. It was designed by Mr A. Atkins, F.R.1.8.A., from drawings furnished by the director, an:! is a modification of that erected

at Rochester. U.S.A., some years ago under the supervision of Prof. Swift. Its form is a sixteen sided base, surpounted by a nearly hemispherical dome. The diameter of the dome is 20 feet, and it rests on walls 10 feet G inches high.

The dome carries two eicles of angle iron on its under side, which rest <ui eight pairs of wheels running looselv on their axles. These wheels again run on two rails, which are fastened concentrically round the top of walls, thus enabling the dome to be revolved to any point of the compass. A segment of the dome can be opened, as shown in the illustration, or closed by the shutter seen to one side (which works with great ease), and ibis opening can be pointed in any direction desired. The large block of masonry seen to the left of, and protruding from, the building, is part of the north pier, on which rests the lower portion of polar axis. The total weight of the two supports for the telescope amount to about GO tons; the weight of the telescope and its mount is between 7 and 8 tons. The object of t ie Society is to draw together all interested in astronomy, to bring into association all observers, whether of a casual or of a more scientific turn, for mutual help and organisation in astronomical studies and observations, ft may be mentioned that this is the first society known to us working on these lines, and its future will be watched with considerable interest. The work connected with displaying the instrument and showing the various objects to .the uninitiated, as well as the care of the observatory, is undertaken voluntarily by the lion. Director and bis honorary staff of assistants, thus ensuring economy in the working of this society.

We understand the society intends as soon as funds will allow .of adding a transit instrument and mean-time clock, a necessary complement to ensure accurate observations. The carrying of this project to a successful issue reflects no small amount of credit on those connected with it, and the go-ahead town of Wanganui is to be complimented on having such a fine equipment in iKmidM, ami we trust its residents will see to it that such a fine educational establishment does not languish for want of ade-

quate support. The obtorvatory was formally opened by the Premier on May-25th, in the presence of a large gathering of townspeople.