[2d Ed.] [Before Flamsteed, the best Catalogue of the Stars was [485] Tycho Brahe’s, containing the places of about 1000 stars, determined very roughly with the naked eye. On the occasion of a project of finding the longitude, which was offered to Charles II., in 1674, Flamsteed represented that the method was quite useless, in consequence, among other things, of the inaccuracy of Tycho’s places of the stars. Flamsteed’s letters being shown King Charles, he was startled at the assertion of the fixed stars’ places being false in the Catalogue, and said, with some vehemence, “He must have them anew observed, examined, and corrected for the use of his seamen.” This was the immediate occasion of building Greenwich Observatory, and placing Flamsteed there as an observer. Flamsteed’s Historia Celestis contained above 3000 stars, observed with telescopic sights. It has recently been republished with important improvements by Mr. Baily. See Baily’s Flamsteed, p. 38.
The French Histoire Céleste was published in 1801 by Lalande, containing 50,000 stars, simply as observed by himself and other French astronomers. The reduction of the observations contained in this Catalogue to the mean places at the beginning of the year 1800 may be effected by means of Tables published by Schumacher for that purpose in 1825.
In 1807, Piazzi’s Catalogue of 6748 stars, founded on Maskelyne’s Catalogue of 1700, was published; afterwards extended to 7646 stars in 1814. This is considered as the greatest work undertaken by any modern astronomer; the observations being well made, reduced, and compared with those of former astronomers. Piazzi’s Catalogue is the standard and accurate Catalogue, as the Histoire Céleste is the standard approximate Catalogue for small stars. But the new planets were discovered mostly by a comparison of the heavens with Bode’s (Berlin) Catalogue.
I may mention other Catalogues of Stars which have recently been published. Pond’s Catalogue contains 1112 Northern stars; Johnson’s, 606; Wrottesley’s, 1318 (in Right Ascension only); Airy’s First Cambridge Catalogue, 726; his Greenwich Catalogue, 1439. Pearson’s has 520 zodiacal stars; Groombridge’s, 4243 circumpolar stars as far as 50 degrees of North Polar distance; Santini’s, a zone 18 degrees North of the equator. Besides these, Mr. Taylor has published, by order of the Madras government, a Catalogue of 11,000 stars observed by him at Madras; and Rumker, who observed in the Observatory established by Sir Thomas Brisbane at Paramatta (in Australia), has commenced a Catalogue which is to contain 12,000. Mr. Baily [486] published two Standard Catalogues; that of the Royal Astronomical Society, containing 2881 stars; and that of the British Association, containing 8377 stars. I omit other Catalogues, as those of Argelander, &c., and Catalogues of Southern Stars.
Of the Berlin Maps, fourteen hours in Right Ascension have been published; and their value may be judged of by this circumstance, that it was in a great measure by comparing the heavens with these Maps that the new planet Astræa was discovered. The Zone observations made at Königsberg, by the late illustrious astronomer Bessel, deserve to be mentioned, as embracing a vast number of stars.
The common mode of designating the Stars is founded upon the ancient constellations as given by Ptolemy; to which Bayer, of Augsburg, in his Uranometria, added the artifice of designating the brightest stars in each constellation by the Greek letters, α, β, γ, &c., applied in order of brightness, and when these were exhausted, the Latin letters. Flamsteed used numbers. As the number of observed stars increased, various methods were employed for designating them; and the confusion which has been thus introduced, both with regard to the boundaries of the constellations and the nomenclature of the stars in each, has been much complained of lately. Some attempts have been made to remedy this variety and disorder. Mr. Argelander has recently recorded stars, according to their magnitudes as seen by the naked eye, in a Neue Uranometrie.
Among representations of the Moon I may mention Hevelius’s Selenographia, a work of former times, and Beer and Madler’s Map of the Moon, recently published.]
I have [already] said something of the observations of the two Herschels on Double Stars, which have led to a knowledge of the law of the revolution of such systems. But besides these, the same illustrious astronomers have accumulated enormous treasures of observations of Nebulæ; the materials, it may be, hereafter, of some vast new generalization with respect to the history of the system of the universe.
[2d Ed.] [A few measures of Double Stars are to be found in previous astronomical records. But the epoch of the creation of this part of the science of astronomy must be placed at the beginning of the present century, when Sir William Herschel (in 1802) published in the Phil. Trans. a Catalogue of 500 new Nebulæ of various classes, and in the Phil. Trans. 1803, a paper “On the changes in the relative situation of the Double Stars in 25 years.” In succeeding papers he pursued the subject. In one in 1814 he noticed the breaking up of the [487] Milky Way in different places, apparently from some principle of Attraction; and in this, and in one in 1817, he published those remarkable views on the distribution of the stars in our own cluster as forming a large stratum, and on the connection of stars and nebulæ (the stars appearing sometimes to be accompanied by nebulæ, sometimes to have absorbed a part of the nebula, and sometimes to have been formed from nebulæ), which have been accepted and propounded by others as the Nebular Theory. Sir William Herschel’s last paper was a Catalogue of 145 new Double Stars communicated to the Astronomical Society in 1822. In 1827 M. Struve, of Dorpat (in Russia), published his Catalogus Novus, containing the places of 3112 double stars. While this was going on, Sir John Herschel and Sir James South published (in the Phil. Trans. 1824) accurate measures of 380 Double and Triple Stars, to which Sir J. South afterwards added 458. Mr. Dunlop published measures of 253 Southern Double Stars. Other Observations have been published by Capt. Smyth, Mr. Dawes, &c. The great work of Struve, Mensuræ Micrometricæ, &c., contains 3134 such objects, including most of Sir W. Herschel’s Double Stars. Sir J. Herschel in 1826, 7, and 8 presented to the Astronomical Society about 1000 measures of Double Stars; and in 1830, good measures of 1236, made with his 20-feet reflector. His paper in vol. v. of the Ast. Soc. Mem., besides measures of 364 such stars, exhibits all the most striking results, as to the motion of Double Stars, which have yet been obtained. In 1835 he carried his 20-feet reflector to the Cape of Good Hope for the purpose of completing the survey of Double Stars and Nebulæ in the southern hemisphere with the same instruments which had explored the northern skies. He returned from the Cape in 1838, and is now (1846) about to give the world the results of his labors. Besides the stars just mentioned, his work will contain from 1500 to 2000 additional double stars; making a gross number of above 8000; in which of course are included a number of objects of no great scientific interest, but in which also are contained the materials of the most important discoveries which remain to be made by astronomers. The publication of Sir John Herschel’s great work upon Double Stars and Nebulæ is looked for with eager interest by astronomers.
Of the observations of Nebulæ we may say what has just been said of the observations of Double Stars;—that they probably contain the materials of important future discoveries. It is impossible not to regard these phenomena with reference to the Nebular Hypothesis, which has been propounded by Laplace, and much more strongly [488] insisted upon by other persons;—namely, the hypothesis that systems of revolving planets, of which the Solar System is an example, arise from the gradual contraction and separation of vast masses of nebulous matter. Yet it does not appear that any changes have been observed in nebulæ which tend to confirm this hypothesis; and the most powerful telescope in the world, recently erected by the Earl of Rosse, has given results which militate against the hypothesis; inasmuch as it has shown that what appeared a diffused nebulous mass is, by a greater power of vision, resolved, in all cases yet examined, into separate stars.