15 23 Occultation of a Tauri (2) 16 31 Reappearance of ditto 9 58 Occultation of 111 Tauri(6) 10 43 Reappearance of ditto Sat 29 11 20 Occultation of 117 Tauri(6) 3rd Ec. R. 12 13 Reappearance of ditto 18 9 Moon's Last Quarter Sun 30 19 41 22 26 7 8.7 8 50 51 7 4'9 THE PLANETS FOR SEPTEMBER. Mercury is at his greatest westerly elongation on the 6th of September, and rises before the sun during the month. Venus reaches her greatest easterly elongation on the last day of the month, and continues to be a brilliant object for about an hour after sunset. Mars is coming into a favourable position for observation, rising about a quarter to eleven o'clock in the evening at the beginning, and about ten o'clock at the end of the month. Decl. +23 II Diameter 8" 2 23 31 8"-6 Illuminated portion of the disc of Mars, 0.873. Jupiter will still be the conspicuous planet of the evening, setting about an hour after midnight on the 1st, and about eleven o'clock on the last day day of the month. 1st R.A. 19 39 18 Decl. 15th " 19 37 20 Saturn is now too near the Sun to be well observed. Neptune is now favourably fixed for observation. 47 17 Decl. + 3 20 6th R.A. 18th 。 46 II 3 13 THE MINOR PLANETS. The following minor planets arrive at opposition this month: INSTRUMENTS, &c. FOR SALE. These Notices, which are restricted to two lines each, are inserted free of charge to subscribers: applications respecting prices and other particulars to be made to the Editor, with a stamped envelope for reply, without which no answer can be sent.-For Advertisements with prices and more complete details, a small charge will be made. N.B.-It is particularly requested that we may be informed when instruments are disposed of, in order that the notice may be withdrawn, and fruitless applications prevented. Achromatic Refractor, 7 in. ap. 9 ft. focus, by Troughton and Simms; 6 eye-pieces; on garden Equatorial, steadying rods, &c. Achromatic Refractor, 6.4 in. ap. 8 ft. focus, by Merz, Equatorial and clockwork by Troughton & Simms. Achromatic Refractor, 4 in. ap. 5 ft. focus, by Dollond; equatorially mounted. Powers up to 400. Achromatic Refractor, 2 in. ap. 4 ft. focus, 3 pancratic eye-pieces, powers 60 to 200, pillar and claw, and garden tripod stand. [61] Achromatic Refractor, 2 in. ap. 42 in. focus, one day and one night eye-pieces, on tall tripod stand. [54] [73] [87] [72] Dialyte Telescope, 44 in. ap. 5 ft. focus, price very low. [88] Gregorian Reflector, 43 in. ap. 2 ft. focus, by Dollond, 4 powers, 50 to 200, finder, &c., on brass table stand. [63] Achromatic Object-Glass, 4 in. ap. 62 in. focus, by Slugg, with brass cap and receiving cell, for mounting on tube. [85] Newtonian Metal Speculum, 8 in. ap. first-class quality. Transit Instrument, 3 in. ap. 5 ft. focus, Ys fitted with agates for mounting on stone piers. [77] [29] Equatorial Stand, for a 5 or 6 ft. telescope: 13 in. circles, divided on silver, to 10" of space and 4s. of time. Has never been used. [55] Varley Stand, improved, rackwork movements, for a telescope of 5 or 6 ft. focus on circular turn-table, to point in any direction. [16] Polar Axis, of mahogany, 7 ft. long, adapted for a 4 ft. telescope, with 12 in. circles, reading to minutes. Speculum Grinding Apparatus, capable of working a 7 ft. speculum: with tube and fittings for a 9 in. Newtonian. Recreative Science: complete in numbers, half-price. [56] [57] [30] INSTRUMENTS, &c. WANTED. Equatorial Telescope, about 6 in. aperture, with driving clock and circles; price moderate. [89] Astronomical Clock, not very first-class; price low. [65] Equatorial Stand, for a 5 ft. Refractor: graduated circles. 35 [71] Monthly Notices of the Royal Astronomical Society, Vol. 3. [26] [82] Bartholomew Prescot on the Universe, published 1823: a copy wanted, in good condition. [84] ASTRONOMICAL REGISTER-Subscriptions received by the Editor. To December 1866. Gribble, Rev. J. H. Lancaster, J. L. Metcalf, Rev. W. R. To June 1867. Main, Rev. R. LIST OF SUBSCRIBERS-Names received since our last number. Birmingham, John, Esq., Millbrook, Tuam. NOTICES TO CORRESPONDENTS. We take the opportunity offered by a few spare lines in the "making-up" of this page to express to our readers the wish that they would resort more than they do to our column of " Brief Correspondence." We are very desirous of making our magazine do for the astronomer what Notes and Queries does for the antiquarian-serve as a resort for enquirers of every grade. The Editor regrets that, owing to his absence from town, the publication of the present number of the Register has been much delayed; he trusts this will not occur again. Several letters, with subscriptions, &c., will be noticed in the next number.-Received for review: Mr. Proctor's Handbook of the Stars. ERRATUM.-No. 44, p. 218, line 5 from bottom, for "Courbe-Caisse" read "Courbaisse." THEA By RICHARD A. PROCTOR, Now ready, with Maps and Diagrams, price 5s. FOR SALE, AN OBSERVATORY, with 5 ft. Equatorial Dollond, Transit and Clock. Also Twenty-six other Instruments.-For particulars, apply to John Nicholetts, Esq., South Petherton. EQUATORIAL TELESCOPE and STAND, by T. SLATER, London.-Object Glass, 9 in. aperture, and 12 ft. 4 in. focal length. This Telescope has been used in a private Observatory three years, and its performance on close double stars guaranteed. It has been removed in consequence of its late owner having purchased of the same maker an object glass of 16 in. diameter. [80] TTBECOSOLD, a brass-mounted.-Eye-pieces, eight negative, 90 to 600; four positive, one day, one nebula, one comet, small diagonal, large diagonal adapter, sun prism, transit, three Barlow lenses; Ramsden's micrometer by Berge, two reading micrometers, a position micrometer with two eye-pieces, graduated on platina, by Troughton & Simms, with slipping piece and illuminating apparatus.-On large garden Equatorial Stand, without circles; with steadying rods, and 5 in. circle on silver with level, adapted to the telescope to find declination when on the meridian. [81] O BE SOLD, a 12-in. SILVERED GLASS SPECULUM, TO ease. [78] The Astronomical Register is intended to appear at the commencement of each month; the Subscription (including Postage) is fixed at Three Shillings per Quarter, payable in advance, by postage stamps or otherwise. The pages of the Astronomical Register are open to all suitable communications. Letters, Articles for insertion, &c., must be sent to the Editor, Mr. S. GORTON, Stamford Villa, Downs Road, Clapton, N.E., not later than the 15th of the month. The Astronomical Register. No. 46. OCTOBER. 1866. STELLAR SPECTROMETRY. (From SECCHI's Bullettino Meteorologico of 31st August 1866.) SPECTROMETERS hitherto used for the study of the stars labour under the great defect of diminishing materially the light of the objects studied; so much so, that if the light of those objects is faint, either it is not possible to apply sufficient magnifying power to distinguish the lines, or nothing can be seen at all. Moreover, they are formed of many pieces which ought to be constructed with the greatest precision, and which render the instruments costly, inconvenient, and difficult to handle. It was a matter of necessity to adapt oneself to these defective conditions whilst there was nothing better, but it was exceedingly desirable to simplify and to improve them, in order to diffuse their use among those who have not great means at their disposal. The spectrometer which we are about to describe corresponds, we hope, to these requirements. It consists simply of one of Amici's prisms, in which the deviation is nil, such as is found in Hoffmann's small spectrometers, and of an achromatic cylindrical lens. The lens is placed in front of and near to the ocular at a sufficient distance, because when placed there only the image of the star is reduced to a luminous thread. Our lens is about three inches focal length. Beyond the cylindrical lens is placed the above-mentioned prism, in such a position that it gives the dispersion of the spectrum perpendicular to the luminous focal line of the star. The ocular for examining the spectrum is that of the telescope, and may be positive or negative; and by augmenting the magnifying power the amount of separation desired can be obtained. The ordinary filar micrometer may be applied, or, what is better, one furnished with two sharp points, which can be moved succes |
