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INSTBUMENTS, &c., WANTED.

Equatorial Stand, Wanted—adapted for a 5 ft. Refractor, with graduated circles ; second hand, at a moderate price. [35]

Monthly Notices of the Royal Astronomical Society.—The third Volume wanted: a good price will be given. [ 26 ]

Schroter*s Selenotopographische Pragmente—a copy wanted, in two volumes. [48]

THE PLANETS FOR OCTOBER.

Mercury may be seen in the mornings for a few days at the heginning of October; it arrives at superior conjunction on the 21st. It is in Lei 1 at the beginning and Libra at the end of the month. 1st R.A. 11 39 39 Dec . N. 4 15 Diameter 5"-6 31st „ 14 46 42 „ S. 16 32J „ 4--6

Venus continues to pass the meridian shortly before ten o'clock in the mornings of October: it is still a splendid object before sunrise, though smaller than during last month. It is in Leo at the beginning and Virgo at the end of the month.

1st R.A. 10 22 48 Dec. N. 11 1 Diameter 13- o 31st „ 12 39 35 „ S. 2 28J „ n '-6

Illuminated portion of the disc of Venus=o-842. Mars is too near the sun to be favourably observed.

Jupiter is in Ophiuchus at the beginning and Sagittarius at the end of the month. It sets at twenty minutes before nine o'clock on the 1st, and at two minutes past seven on the 31st. 1st E.A. 17 26 41 Dec. S. 23 6 3lBt „ 17 47 34 „ 23 21

Saturn arrives at conjunction with the sun on the 26th of this month, and is therefore unfavourably fixed for observation.

Uranus is now well situated for the telescope, remaining visible throughout the night in the constellation Gemini. 4th E.A. 6 17 20 Dec. N. 23 38 28th „ 6 16 43 „ 23 38J

Neptune is also favourably situated for observation, in the constellation Pisces, about two degrees north of the equator.

4th R.A. 0 36 o Dec . N. a 10 28* ., o 33 39 ,, 2 o

THE MINOR PLANETS.

The following are the Minor Planets which will arrive at opposition this month: full particulars will be found in the Supplement to the Nautical Almanac for 1868.

Magnitude. Eight Ascension. Declination.

Irene 10-5 October 8 I 51 S. 1 48

Thetis 10-4 ., 1 56 N. 2 34

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ECLIPSE OF THE MOON.

A partial Eclipse of the Moon, visible at Greenwich, will take place on Wednesday evening, October 4th, about half past 8 o'clock.

GREENWICH MEAN TIME.

First Contact with the Penumbra

Frst Contact with the Shadow

Middle of the Eclipse

Last Contact with the Shadow

Last Contact with the Penumbra

The first contact takes place 1280 from the north point of the moon's limb towards the east, and the last contact 162° from the same point towards the west, for direct image.—Magnitude of the Eclipse (moon'sdiameter=l)o~342.

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ECLIPSE OF THE SUN.

An Annular Eclipse of the Sun, partly visible (as a partial eclipse) at Greenwich, will take place on Thursday, October 19th, shortly after 4 oclock in the afternoon.

GREENWICH MEAN TIKE. h. in.

Beginning of Eclipse 4 12

Greatest Phase 5 9

The sun sets at Greenwich at three minutes before 5 o'clock.—The first contact takes place 1190 from the sun's north pole, towards the west, for direct image.—Magnitude of the Eclipse (sun's diameter = 1) 0316.

ASTRONOMICAL EEGISTEE.

LIST OF SUBSCRIBERS- Names received since our last number. Worthington, Robert, Esq., F.R.A.S., 96, King Street, Manchester.

ASTRONOMICAL REGISTER—Subscriptions received by the Editor for 1865.

To June. Holland, Rev. G To December. To June, 1866.

Thrustans, J Huggins, W Lancaster, J, L Tupman, G. L

Mitchell, H. J Leigh, J

To September. Nealds, J Strange, Col.

Barneby, T Oldfield, W Vertu, J

Brothers, A Wheeler, W.H Worthington, E,

August 23, 1866. Wigner, G. W

NOTICES TO CORRESPONDENTS.

We have given with this number part of the Tables, &c., for October, as the Editor may be out of town at the beginning of that month.

Received—Mr Proctor's Saturn and its System. Also, IAst of Celestial Objects, from Mr Brodie.

Several communications are unavoidably postponed.

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: Letfers.Articles for insertion,&c.,must be sent to the Editor, Mr 8.go~rtotz, Stamford Villa, Downs Road, Clapton, N.B., not later than the 15th of the month.

ASTRONOMICAL REGISTER: APPENDIX TO No. 33.

THE REV. W. A. DARBY'S "ASTRONOMICAL
OBSERVER."

TO THE EDITOR OF THE ASTRONOMICAL REGISTER.

Sir,—I regret that, having perused Mr. Darby's letter in your number for this month, in reply to my notice of some errata in his Astronomical Observer, I feel it incumbent on me, in justice to myself and to others, to refer again to the subject. But first let me express my regret that I did not in every instance consult the list of corrigenda. The fact is, that having, at the commencement of my inspection of the work, consulted it in vain with respect to several of the most considerable errors I met with, I subsequently omitted to look for one or two of the rest.

1. Mr. Darby excuses his mistake in the very simple operation of deducing Greenwich mean time from local sidereal time under a different meridian, by informing us that his "method is based on the formuke of the Nautical Almanac" and that "a slight error has arisen from not embracing the whole of the decimal figures, but it is sufficiently accurate for the amateur." And he adds, " This method has been in use for some years at three observatories in Manchester." This is a serious acknowledgment, and will have its effect in lowering the character for accuracy of our amateur observatories. But, by his excuse, Mr. Darby confesses his extraordinary misapprehension of the explanation given in the N. A., and, at the same time, his unacquaintance with the subject. For the reduction of Manchester S.T. to G.M.T., he has employed the N. A. method of reducing Greenwich S.T. to G.M.T.,—merely adding to it the longitude in time without correction. In so doing he has entirely ignored the instruction in the paragraph commencing—" If the place of observation be not on the meridian of Greenwich, &c."!—Surely he must mistake in asserting that such is the practice of three observatories in Manchester! Yet Mr. Darby's apologist, who signs "A. B." and dates from Manchester, is also of opinion that Mr. Darby's mistaken copying from the N. A. absolves him from all blame! If Mr. Darby will test the G.M.T. produced by his own method in Example I. (which should be 7h. 26m. 11'61s. when his error in the reduction of the given sidereal time into mean time is corrected, the seconds being 35-01s. instead of 34/90S.), by reducing it back again into Manchester S.T. by his own method in Example II., he will find the result will be too great by 1-463.; which is the amount of the retardation of meantime in 8m. 52s. of sidereal time.

2. Mr. Darbv excuses his omission of the epoch belonging to Smyth's List of Test Objects by the assumption that all the readers of the Astronomical Observer must be acquainted with that epoch. A very unlikely thing, if they do not possess the "Cycle;" and if they do, they have the list already. Plainly, the epoch should have been given in this instance, as well as in all others in which the distances of binary stars are stated.

3. By stating that the omission of the epoch is a fault "pervading the whole book," it must surely be obvious that I referred to its being found in various parts of the work, and not, for instance, in the early part only, but afterwards in most cases supplied.

4. I have already borne a cordial testimony to the general correctness of Admiral Smyth's learned and interesting "Cycle of Celestial Objects;" but the author himself would be one of the last to claim for it a character of infallibility; and the articles 702 and 703 in vol. ii. constitute a very curious instance of mistaken identity. With respect to No. 703 (which = 186 Pxix. and is identical with lpi. 13), it is to be regretted that Mr. Darby should have missed the opportunity of calling the attention of amateurs to the small star which constitutes it triple, with a view to ascertain whether there is any solid ground for supposing it to be variable. It is certainly an extraordinary fact, that though observed by Herschel I. as triple, this object should never have been recognised as such, either by South at Passy, or by Herschel II., or by Struve at Dorpat (who measured it on five nights as double only), or by Jacob, or by Smyth, and yet, after lying hid for nearly eighty years, should have been seen at the first glance in 1859 by the aid of a telescope much inferior in optical power to Struve's. All this is surely sufficient to constitute it an object of special interest; and I cannot but regret that Mr. Darby should have been quite unaware of the rectification of the mistakes about it (and also about 185 P xix.) which was inserted in the Monthly Notices of the R. A. S. for November 1862.

6. In this section Mr. Darby refers to myself, among others, as having given to { Scorpii the designation of $ Libra. Yet he adds— "According to Admiral Smyth, Argelander, and even Mr. Dawes, 5 Librae is a misnomer for 51 Librae, and the star is properly J Scorpii." The only instance, I believe, in which I designated it £ Libra was in my first series of measures of double stars made at Ormskirk in 18 30-18 34. In that I inadvertently followed Flamsteed's Atlas, and his Calalogue edited by Baily; and Herschel's nomenclature of the star as 5 Librae=51 Librae of Flamsteed." But in my second series of observations (1834-1839) I termed it { Scorpii: and in the edition of the small Maps of the Useful Knowledge Society, which I revised in 1840,I restored the star to Scorpio, and altered the boundary-line of the constellation so as to include it. In the doublestar measures of Herschel and South, and in those of South at Passy, it is also termed I Scorpii: and Argelander, whose accuracy in such matters is superior to that of any other author, has simply given it as £ Scorpii in the Catalogue and Atlas of his admirable Uranometria Nova. If Malby has given £2 as duplex, that fact so far detracts from his character for accuracy. It is simply a blunder, as was Flamsteed's, including t>oth y and K Scorpii in Libra'mA designating them as 20 and 51 Libra. Those two conspicuous stars originally pointed out the two anterior claws (forficula) of the Scorpion; and so they are placed in Argelander's excellent Atlas. Surely it is high time that his example should be universally followed, and an end put to all the confusion which has arisen from Flamsteed's erroneous entry of these two starMr. Baily, in his edition of Flamsteed's Catalogue, says in a note ou No. 2192 of that Catalogue,—" 2192. 51 Libra. This star is called 5 in the British Catalogue; but that letter has been already affixed to 13 and 15 Libra. It is the 5 Scorpii of Bayer, and consequently ought not to have been introduced into this constellation. I have, therefore,

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