Chapter XVII: Nebulæ and Clusters of Stars (2)

[55] Sir W. Herschel at first entertained this view, finding that with every increase of telescopic power more nebulæ were resolved. But in 1791 he said, “perhaps it has been too hastily surmised that all milky nebulosity is owing to starlight only.” Lacaille had remarked in 1755 that “it is not certain the whiteness of parts of the Milky Way is caused by clusters of stars more closely packed together than in other parts of the heavens.”

[56] This is exclusive of 47 new nebulæ discovered by Prof. Safford, which form the appendix to the catalogue.

[57] Chambers says only four examples are known, but this is erroneous, as Lord Rosse’s telescope has added five ring-nebulæ to the four previously catalogued.

[58] Some of the nebulæ in Messier’s list were discovered by Mechain at Paris, who, like Messier, earned celebrity by his cometary discoveries. He was born at Laon in 1744, and died at Valencia in 1805.

[59] O. Struve had expressed views identical with these in 1857 (see ‘Monthly Notices,’ vol. xvii. p. 230).

[60] Humboldt says this “name is evidently derived from the voyage of Magellan, although he was not the first who observed them.”

[61] I have selected the various objects in these lists from the New General Catalogue.

[62] These forms are more numerous than the annular nebulæ. They often exhibit a blue colour, and the spectroscope shows them to consist of gas.

NOTES AND ADDITIONS.

LARGE AND SMALL TELESCOPES.

P. 19.—With reference to mountainous sites for large instruments, a remark in Sir Isaac Newton’s ‘Opticks’ (1730) may be quoted:—“Telescopes ... cannot be formed so as to take away that confusion of rays which arises from the tremors of the atmosphere. The only remedy is a most serene and quiet air, such as may perhaps be found on the tops of the highest mountains above the grosser clouds.”

P. 27.—Lieut. Winterhalter, of the United States Navy, recently visited a large number of European observatories, and in describing that of Nice says:—“M. Perrotin declares that two hours’ work with a large instrument is as fatiguing as eight with a small one, the labour involved increasing in proportion to the cube of the aperture, the chances of seeing decreasing in the same ratio, while it can hardly be said that the advantages increase in like proportion.” The Nice Observatory, and its splendid instruments (including a 30-inch refractor), are due to the munificence of M. Bischoffsheim, who has expended about five million francs upon them.

P. 36.—The large refractor to be erected on Wilson’s Peak of the Sierra Madre range of mountains, in Southern California, is to be 40 inches in diameter. The rough unground disks of glass are already in the hands of the Clarkes, of Cambridgeport, Mass. It is estimated that the complete object-glass and cell will cost something like $65,000, and the focal length of the instrument will be about 58 feet.

THE SUN.

P. 100.—The last minimum of sun-spot frequency appears to have occurred at the middle of 1889. Conspicuous spots were very rare in the first half of 1890, but some fine groups were presented in the last half of the year. On Aug. 31 I saw a group extending over 113,000 miles in length, and on Nov. 27 there was another, which measured 123,700 miles.

P. 111.—Thompson’s cardboard disks have been favourably spoken of as enabling observers to determine the positions of spots at any season of the year.

MERCURY.

P. 137.—At the meeting of the British Astronomical Association on Nov. 26, 1890, Mr. G. F. Chambers expressed his firm belief in the existence of an intra-Mercurial planet. The President (Capt. W. Noble) in his inaugural address pointed out the desirability of effecting further observations, both of Mercury and Venus, with a view to redetermine their rotation-periods. He justly remarked that moderately small instruments might be fittingly employed in the work, and that Schiaparelli’s deductions (mentioned on pp. 142 and 149) ought to be accepted with extreme reserve pending their verification.

MARS.

P. 160.—Prof. W. H. Pickering observed some of the canals on Mars in 1890 with a 12-inch refractor, but was not able to double any of them. He says that, in examining these objects, the power employed should not “exceed one or two hundred.” This is quite contrary to the advice of others, who recommend high magnifiers; and perhaps it accounts for Prof. Pickering’s failure in recognizing the duple canals.

With the great 36-inch refractor Mr. Keeler saw, on July 5 and 6, 1890, some curious white spots on the edges of the gibbous limb of Mars, something similar to those visible on the unilluminated part of the lunar disk. The canals were observed as feeble diffused bands. The two satellites were seen by a lady visitor, though previously unaware of their existence.

P. 161.—The method of deriving the rotation-period of Mars is exemplified by Mr. Proctor in the ‘Monthly Notices,’ vol. xxviii. p. 38. An interesting paper, “On the Determination of the Rotation-Period of Jupiter in 1835,” will be found in the ‘Memoirs,’ vol. ix.

PLANETOIDS.

P. 167.—The 308th planetoid was discovered by Charlois on March 5, 1891.

JUPITER.

P. 170.—Dupret, in Algiers, saw Jupiter with the naked eye on Sept. 26, 1890, and following days, twenty minutes before sunset.

P. 191.—M. Guillaume, during a recent transit of the shadow of Jupiter’s second satellite, observed a duplicate shadow, fainter than the ordinary one, which partly covered its southern side.

COMETS.

P. 250.—On Nov. 16, 1890, Dr. Spitaler, while looking for Zona’s Comet with the 27-inch refractor of the Vienna Observatory, discovered a new and very faint comet only 23′ distant from the object of his search. That two of these bodies should be found almost simultaneously and so near together must be regarded as a very singular coincidence.

METEORS.

P. 261.—Mr. Proctor held the view that certain meteorites may have originally been ejected from the Sun. A recent writer thus summarizes our knowledge of them:—“That they are independent bodies, moving in orbits of their own in space; that these dark bodies are abundant in the interplanetary spaces; that those within the near range of solar or planetary attraction move with great velocity; that many swarms of them follow well-known orbits; and that, in general, their origin is undoubtedly the same as that of other celestial bodies” (‘Sidereal Messenger,’ June 1890, p. 284).

P. 267.—On May 2, 1890, a brilliant fireball, leaving a long train of fire and smoke, and exploding with a noise like thunder, was seen at many places in Northern Iowa, Minnesota, U.S.A. Some fragments of the meteor fell on a farm a few miles from the south line of Minnesota. The largest piece was sold by auction for $100, but it soon transpired that the person who sold it was only the lessee and not the owner of the ground on which the meteor fell. The aerial visitor and its purchase-money were therefore peremptorily seized by legal authorities, pending the decision of a Court of Justice as to the rightful ownership.

P. 267.—On December 14, 1890, at 9^h 42^m a large fireball of dazzling lustre, and giving a report like thunder, was widely observed in the southern parts of England. At the end-point the fireball appears to have been only 8 miles in height, and over a point near Brentwood, in Essex.

THE STARS.

P. 309.—Prof. Chandler, of Cambridge, Mass., estimates that the total number of variable stars visible with a common field-glass is about 2000, but with a large telescope there are probably hundreds of thousands within reach. He further states that quite five sixths of the variable stars are reddish in colour, and that the redness is usually a function of the length of the period of variation. The redder the star the longer its period.

P. 312.—In a recent communication to the Academy of Sciences, M. Lescarbault (the alleged discoverer of Vulcan in 1859) announced that on the night of January 11, 1891, he discovered a bright body in Leo which he could not identify in any star-map, and hence concluded it to be a new star, or one suddenly increased in brilliancy. The “new star,” however, subsequently turned out to be the planet Saturn! This ridiculous mistake (so easily avoidable with a little care) will naturally divest the supposed discovery of Vulcan of the importance attached to it by some writers, for M. Lescarbault obviously lacks the experience and caution necessary to command credit.

NEBULÆ AND CLUSTERS OF STARS.

P. 327.—Mr. Roberts, from a comparison of his photographs, has found distinct evidence of variability in the nucleus of the great nebula in Andromeda. In some of the photographs the nucleus is shown to be stellar, while in others there is no trace of this. Mr. Roberts remarks:—“We may reasonably infer that the nucleus of the nebula is variable, and that it will be practicable to study the character of the variability without the necessity of giving long exposures of the plates.” The period of the variation has now to be determined, and it is advisable that telescopic observations of the nucleus should be made with the view of confirming the photographic results. It would be premature to regard the changes as demonstrated before they have been submitted to thorough investigation.

P. 327.—In the _Comptes Rendus_ for March 2, 1891, M. Bigourdan has a paper on the variability of the nebula N.G.C. 1186, situated near Algol. This nebula was discovered by Sir W. Herschel in 1785, and though Sir J. Herschel re-observed it in 1831, Lord Rosse looked for it without success in 1854 and 1864. On Nov. 8, 1863, D’Arrest failed to detect the nebula, though he searched for it with assiduity at a time when the sky was very favourable. He was led to conclude that the object did not exist. M. Bigourdan finds that the nebula is again visible in the position indicated by the two Herschels, viz. R.A. 2^h 54^m 20^s, Dec. +42° 10′, he having observed it on Jan. 31 and Feb. 26, 1891. It is difficult to believe that this object could have escaped the scrutiny of Lord Rosse and D’Arrest in 1854, 1863, and 1864; hence the variation is probably real. The nebula may be easily found, as it is very near the binary B.D. +42° (1123 G.C.), the position of which for 1891 is R.A. 2^h 58^m 6^s, Dec. +42° 29’ (‘Nature,’ March 12, 1891).

P. 329.—While examining the Pleiades on the night of November 14, 1890, Mr. Barnard discovered a new and considerably bright, round, cometary nebula 36″ S. and 9″ following Merope. The reason why this nebula has not been detected by photography is because it is so near Merope that the over-exposed light from the star obliterates it. But it is certainly very strange that the object alluded to has never been telescopically discovered before; for the Pleiades have been scrutinized repeatedly with all sorts of telescopes, and particularly since Tempel announced his discovery of a large faint nebula involving Merope in 1859. Mr. Barnard says the new nebula is 30″ in diameter, and that it is visible in a 12-inch refractor when Merope is hidden with a wire.

INDEX.

Action in Sun-spots, Cyclonic, 108.

Active volcanoes on the Moon, 120.

Adams theoretically discovers Neptune, 222.

Advantage of Equatoreals, 54.

Aerolites, 264.

Air and water on the Moon, Absence of, 115.

Algol, 310.

Alleged satellite of Venus, 152.

Almanacks, 83.

Alphabet, Greek, 287.

Alpine Valley, 127.

Altitudes of markings on Jupiter, 185.

Amateur’s first view of Mercury, 139.

Ancient ideas concerning meteors, 260.

Andromeda, Great Nebula in, 334.

Andromedes, 276.

Angles of Position, Measurement of, 291, 306.

Announcement of a new comet, 244.

Annual rate of cometary discoveries, 255.

Antares, 309.

Anthelme, Discoverer of a new star in 1670, 313.

Apennines, 132.

Aperture and Power required for Comet-seeking, 252.

Apparitions, Meteoric, 261.

Appearance of Comets, 228.

—— of Mars, 155.

Aquarids, 275.

Archimedes, 127.

Argelander’s magnitudes of stars, 294.

Aristarchus, 120.

Ascertaining positions of Comets, 257.

Aspect of the rings of Saturn, 204.

Atmosphere of Jupiter, 177.

—— of Mars, 161.

—— of Mercury, 139.

—— of Venus, 151.

Atmospheric undulations, 29.

Attractions of Telescopic work, 85.

Auwers, Discoverer of a new star in 1860, 314.

Bacon, Roger, Early hints on refracted rays, 3.

Barnard, His cometary discoveries, 255.

—— observes Brooks’s multiple Comet, 239.

—— observes new stars in the Trapezium, 319.

—— observes a new nebula in the Pleiades, 351.

Beauty and brilliancy of Venus, 145,

Belts of Sun-spots, 104,

—— on Jupiter, 172.

—— on Saturn, 198.

—— on Uranus, 218.

Berthon’s dynamometer, 50.

Biela’s Comet, 238.

Bigourdan observes a variable Nebula, 351.

Binary Stars, 300.

Birmingham discovers a new star in 1866, 314.

Bond, G. P., discovers Crape-ring of Saturn, 202.

Brahe’s, Tycho, new star of 1572, 312.

Bright objects near the Sun, 107.

Brightness and position of Jupiter, 170.

Brooks on Comet-seeking, 253.

—— on Occultation of Jupiter, 187.

—— on Shower of telescopic Meteors, 272, 274.

Brooks’s double Comet of 1889, 239.

Brorsen’s Comet, 239.

Browning and reflecting-telescopes, 60.

Brunowski discovers a new star, 313.

Burnham, Discoverer of double Stars, 31, 320.

—— discovers a group of 18 new nebulæ, 341.

——, Measures of the companion to Sirius, 307.

—— on the inutility of “stops,” 58.

Calver compares light of reflectors and refractors, 37.

——, Maker of glass specula, 16, 17.

Canal-shaped markings on Mars, 159.

Canis Majoris α, 307.

Cassegrain’s reflecting-telescope, 10.

Cassini, Diameter of his object-glasses, 9.

—— discovers four satellites and the divided ring of Saturn, 9.

——, Observations of Jupiter, 172.

——, —— of Saturn, 198.

——, —— of Venus, 147.

Celestial Globe, 63.

Centauri α, Diameter and distance, 299.

Ceres, 168.

Chambers on Coloured Stars, 316.

—— on the intra-Mercurial Planet, 348.

Chandler on Variable Stars, 350.

Changes, Lunar, 120.

—— on Jupiter, 182.

—— on Mars, 163.

—— on Saturn, 206.

Charts of Mars, 158.

Cheapness of Telescopes, 57.

Choice of Telescopes, 38.

Clark, Alvan, & Sons, make large object-glasses, 18.

——, discovers the companion to Sirius, 307.

Cleaning lenses, 59.

Clusters of Stars, 317.

Coggia’s Comet of 1874, 233.

Colour of Jupiter, 171.

—— of Mars, 155.

—— of Saturn, 195.

—— of Uranus, 217.

Colouring of the eclipsed Moon, 119.

Colours of Stars, 315.

Coma Berenices, 317.

COMETS AND COMET-SEEKING, 227.
Ideas concerning Comets, 227.
Appearance of Comets, 228.
Large number visible, 228.
Nature of apparition, 229.
Tenuity, 229.
Differences of orbit, 230.
Discoveries of Comets, 230.
Large Comets, 231.
Periodical Comets, 234.
Halley’s Comet, 236.
Encke’s Comet, 236.
Biela’s Comet, 238.
Brooks’s double Comet, 239.
Brorsen’s Comet, 239.
Faye’s Comet, 240.
D’Arrest’s Comet, 240.
Pons-Winnecke’s Comet, 240.
Tuttle’s Comet, 241.
Grouping of Periodical Comets, 241.
Further Observations required, 243.
Nomenclature of Comets, 246.
Curiosities of Comets, 248.
Naked-eye Comets, 248.
Comet-seeking, 249.
English weather and Comet-seeking, 251.
Aperture and Power required, 252.
Annual rate of discovery, 255.
Telescopic Comets, 256.
Ascertaining positions, 257.
Dr. Doberck’s hints, 258.
Prizes for Discoveries, 258.

Common, His large Reflectors, 15;
Their performance, 28.

Computation of a Meteor’s real path, 278.

Conjunctions, Planetary, 225.

Constellation figures, The, 290.

Cooke & Sons mount a 24·8-inch refractor, 18;
Its barren record, 25.

Copernicus, 127.

Course of the Milky Way, 296.

“Crab” Nebula in Taurus (M. 1), 336.

Crape-ring of Saturn, 202.

Crucis κ, Cluster at, 318.

Curiosities of Comets, 248.

Cyclonic action in Sun-spots, 108.

Cygnus, Nebulous streams in, 339.

Dallmeyer on Dividing power, 293.

D’Arrest’s Comet, 240.

Dawes’s observations of Jupiter, 173.

—— observations of Saturn’s Crape-ring, 202.

——, On Dividing power, 292.

—— Solar Eyepiece, 92.

Definition in towns, 81.

Deimos, Outer Satellite of Mars, 165.

Democritus explains the Milky Way, 2.

Dennett announces the Red Spot on Jupiter, 173.

Denning’s Comet, 243.

Denza on the Meteors of Nov. 27, 272.

Derham, his list of Nebulæ, 327.

Description of Nebulæ and Clusters of Stars, 333.

Determination of the Sun’s rotation-period, 104.

Detonating Fireballs, 267.

Dewing of Mirrors, 62.

Diffraction-rings, 293.

Dimensions of Nebulæ and Scar-clusters, 332.

—— of Sun-spots, 94.

Disappearance of Saturn’s ring, 205.

Discordant observations of Saturn, 204.

Discoveries of Comets, 230.

—— of Nebulæ, 341.

Discovery of Neptune, 221.

—— of Planetoids, 167.

—— of Uranus, 215.

Distance of the stars, 299.

Distinction between Nebulæ and Star-clusters, 324.

Distribution of Nebulæ in R.A., 326.

Disturbances, Recurrent solar, 110.

Dividing power, 292.

Divisions in outer ring of Saturn, 201.

Doberck, Dr., On the Invention of the Telescope, 5.

——, On Comet-seeking, 258.

Dollond patents his Achromatic Telescope, 12.

——, His object-glasses, 16.

Donati’s Comet of 1858, 233.

Dörfel mountains, 131.

Double Comets:—
Biela’s, 238.
Brooks’s, 239.

—— Nebulæ, 332.

—— Stars, 300, 302.

Draco, planetary nebula in, 335.

Drawing, 73.

Drawings of Jupiter, 185.

Dumb-bell Nebula (M. 27), 337.

Duration of meteor-flights, 282.

Duration of Silver-on-glass films, 60.

Dynamometer, Berthon’s, 50.

Early observations of Jupiter, 172.

—— —— of nebulæ and star-clusters, 326.

—— —— of Neptune, 222.

—— —— of Saturn, 197.

—— —— of the Sun, 88.

—— —— of Uranus, 216.

—— —— of Venus, 147.

Earthshine on the Moon, 116.

Eccentric position of Saturn’s rings, 204.

Eclipses of Jupiter’s satellites, 189.

—— of the Moon, 118.

—— of the Sun, 97.

Elger’s lunar observations, 127, 131.

—— Drawings of lunar objects, 129, 130, 132.

Ellipse, 230.

—— on Jupiter, Gledhill’s, 173.

Elliptical nebulæ, 338.

Elongations of Mercury, 138.

—— of Venus, 145.

Encke’s Comet, 236.

—— division in Saturn’s ring, 202, 208.

English weather and Comet-seeking, 251.

Equatoreal spots on Jupiter, Bright, 175, 181.

—— ——, Dark, 181.

Equatoreals, Advantage of, 54.

Exceptional position of Sun-spots, 111.

Eyepiece, Field of, 50.

Eyepieces, 46.

——, Single-lens, 47.

Fabricius observes Sun-spots, 89.

Faculæ, Sudden outburst of, 108.

Faint objects, Observation of, 72.

Faintness of the markings on Venus, 150.

Falls of stone and iron, 266.

Faye’s Comet, 240.

Field of eyepiece, Diameter of, 50.

Figures, The Constellation, 290.

Fireball of Nov. 23, 1877, 267.

Fireballs, 267.

——, Heights of, 268.

First view of Mercury, Amateur’s, 139.

Formations, Lunar, 123.

Foucault parabolizes and silvers glass Speculæ, 15.

Fracastor, His remarks on lenses in 1538, 4.

Friendly Indulgences, 74.

Future, Past and, 84.

Future eclipses of the Moon, 118.

—— —— of the Sun, 98.

Galaxy, or Milky Way, The, 295.

Galilei and the invention of the Telescope, 2, 4, 5.

——, Discovery of Jupiter’s satellites, 187.

——, His first instrument and discoveries, 6, 7.

Galle observes Saturn’s crape-ring, 202.

—— observes Neptune, 222.

Geminids, 276.

Glass, Opera, 61.

Gledhill’s ellipse on Jupiter, 173.

Globe, Celestial, 63.

Globular clusters. 338.

—— ——, List of, 344.

Gore, Diameter of α Centauri, 299.

——, Dimensions of a Star-cluster, 332.

——, Stellar distribution, 294.

Greek alphabet, 287.

Gregory invents a reflecting-Telescope, 10.

Grimaldi, 129.

Grouping of periodical Comets, 241.

Groups of Stars, 316.

Grubb, Maker of a 4-foot Cassegrainian reflector, 14;
Performance of, 25.

——, Maker of a 27-inch refractor, 18;
Performance of, 27.

Hall, Chester More, invents achromatic Object-glass, 11.

Hall, Prof., discovers a white spot on Saturn, 199.

——, Observations of Saturn’s satellites, 213.

—— on the great Washington refractor, 26.

——, Remarks on large and small telescopes, 31.

Halley’s Comet, 236.

—— list of Nebulæ in 1716, 326.

Harriot, Early observer of Sun-spots, 89, 90.

Hartwig, Discovers a new Star in Andromeda, 315.

Heights of Fireballs, 268;
of Meteors, 277.

Heis, His labours in Meteoric astronomy, 262.

Hencke, Discoverer of Planetoids, 167.

Henry, Bros., make a 30-inch refractor, 18;
Performance of, 27.

—— observe the belts on Uranus, 218.

Herschel, Prof. A. S., observes meteors, 262.

Herschel, Sir J., Comet of 1861, 233.

——, Description of k Crucis, 318.

——, Disappearance of Saturn’s ring, 205.

——, Rediscovers Uranus, 219.

——, Satellites of Uranus, 220,

——, Texture of Comets, 229.

——, Thickness of Saturn’s ring, 205.

——, Trapezium of Orion, 318, 320.

Herschel, Sir W., and Cometary discovery, 231.

——, His discovery of Nebulæ, 327.

——, His discovery of nebulous Stars, 330.

——, His discovery of Uranus, 215;
of Satellites, 220.

——, His method of observing Sun-spots, 91.

——, His observations of Jupiter, 182.

——, His observations of Mercury, 142.

——, His observations of Saturn, 199.

——, His observations of Venus, 149.

——, Nucleus of Comet of 1811, 232.

—— observes Binary Stars, 300, 306.

——, Performance of 4-ft. reflector, 21.

——, Remarks on eyepieces, 47.

——, Rotation of Jupiter’s Satellites, 189.

——, Singular figure of Saturn, 196.

Herschel’s, Sir W., Telescopes, 12, 13, 39.

Hevelius, diameter of his object-glasses, 9.

Hind, Discoverer of a new Star in 1848, 314.

——, Discoverer of Planetoids, 167.

——, Discoverer of a variable Nebula, 328.

Hipparchus forms a Star-catalogue, 312.

Hoek on the origin of Comets, 243.

Hooke’s observations of Jupiter, 172.

Hough’s observations of Jupiter, 174, 182.

Howlett’s observations of Sun-spots, 101, 102.

Huygens on the invention of the Telescope, 2.

——, Discoveries on Saturn, 8, 198.

——, Length of his instruments, 8.

Huygens’s Negative eyepiece, 8, 46.

Hyginus, The rill or cleft of, 130.

Hyperbola, 230.

Identity of Meteors and Comets, 262.

Increasing number of Telescopes, 57.

Intra-Mercurial Planet, 137.

Jansen, Zachariah, Inventor of the Telescope, 4.

Johnson’s projections of Solar Eclipses, 99.

Juno, 168.

JUPITER, 170.
An interesting object, 170.
Brightness and position, 170.
Period &c., 171.
Belts and spots, 172.
Observations of Hooke, Cassini, and others, 172.
The “Ellipse” of 1869-70, 173.
The red spot, 173.
Rotation of red spot, 175.
Rotation of bright equatoreal spots, 175.
Rotation of dark spots in N. hemisphere, 175.
Rotation-period, 176.
Nature of the red spot, 177.
Bright equatoreal spots, 181.
Dark equatoreal spots, 181.
New belts, 182.
Changes on the planet, 182.
Further observations required, 183.
Occultations by the Moon, 185.
The four satellites, 187.
Their eclipses, occultations, and transits, 189.
The planet without visible satellites, 192.
Spots on the Satellites, 193.
Occultation of a Star by Jupiter, 193.

Keeler, White spots and canals on Mars, 348.

Kitchiner, The inutility of large Telescopes, 35.

——, Singular form of Saturn, 196.

Klein’s supposed new crater near Hyginus, 122.

Large and small telescopes compared, 20.

—— Comets, 231.

—— number of Comets, 228.

—— refractor intended for California, 36, 347.

Lassell, His large reflecting-telescopes, 14;
Their performance, 24.

—— discovers the satellite of Neptune, 224.

—— glimpses a belt on Uranus, 217.

Leander McCormick refractor, 26.

Learning the names of the Stars, 287.

Leibnitz mountains, 131.

Le Mairean or Herschelian telescope, 13.

Lenses, Cleaning, 59.

—— out of centre, 55.

Leonids, 276.

Lescarbault rediscovers Saturn, 350.

Le Verrier, Theoretical discoverer of Neptune, 222.

Lick, James, Founder of the Lick Observatory, 18.

Lick refractor, Performance of the, 27.

Light of Comets, Fluctuating, 245.

Limited means no obstacle, 51.

Lippersheim, Hans, Inventor of the telescope, 4, 5.

Lunar changes, 120.

—— formations, 123.

Lyræ α, 308.

Lyrids, 275.

Mädler’s observations of Lunar objects, 127, 131.

—— —— of Mars, 158.

—— —— of Venus, 149.

Magellanic clouds, 331.

Magnitudes of Stars, 294.

Marius, Simon, observes Jupiter’s satellites, 6.

—— observes Nebula in Andromeda, 326.

Markings on Mercury, Surface-, 142.

—— on Venus, 147.

—— ——, Faintness of, 150.

MARS, Appearance of, 155.
Period &c., 155.
Phase, 156.
Surface-configuration, 156.
Charts and nomenclature, 158.
Discovery of satellites and canal-shaped markings, 159.
Summary of observations, 160.
Rotation, 161.
Further observations required, 162.
Changes on the Planet, 163.
Satellites, 164.
Occultations by the Moon, 166.

Martin’s 4-foot reflector at Paris, 15;
Its performance, 25.

—— 29-inch refractor at Paris, 18.

Maunder on Sun-spots, 93.

Maxima and minima of Sun-spots, 100.

Means of measurement, 290.

MERCURY, 137.
Supposed planet Vulcan, 137.
Visibility, 138.
Period &c., 138.
Elongations, 138.
Amateur’s first view, 139.
Phases, 139.
Atmosphere, 139.
Telescopic observations, 140.
Schiaparelli’s results, 141.
Observations of Schröter and W. Herschel, 142.
Surface-markings, 142.
Transits across the Sun, 143.
Occultations, 144.

Messier, The Comet-hunter, 249.

Messier’s lists of Nebulæ, 327.

—— large Comet of 1769, 232.

METEORS AND METEORIC OBSERVATIONS, 260.
Ancient ideas, 260.
Meteoric apparitions, 261.
Radiation of Meteors, 262.
Identity of Meteors and Comets, 262.
Aerolites, 264.
Fireballs, 267.
Heights of Fireballs, 268.
Meteorite from Biela’s Comet, 270.
Differences of motion, 271.
Nomenclature of Meteor-systems, 271.
Meteor-storms, 271.
Telescopic Meteors, 272.
Meteor-showers, 274.
Varieties of Meteors, 276.
Meteor of Dec. 28, 1888, 277.
Average heights of Meteors, 277.
Computation of Meteor-heights, 278.
Meteoric observations, 279.
Meteors and terrestrial objects, 284.
—— and gales of wind, 285.

Method, 78.

Milky Way or Galaxy, 2, 295.

Minimum of Sun-spots, 347.

Mirrors, Dewing of, 62.

MOON, Attractive aspect of the, 113.
Diameter and distance, 114.
Crateriform aspect, 114.
Absence of air and water, 115.
Only one hemisphere visible, 115.
Earthshine, 116.
Telescopic observations, 116.
Eclipses, 118.
Physical changes, 120.
Active volcanoes, 120.
Crater Aristarchus, 120.
—— Linné, 121.
—— near Hyginus, 122.
General description of formations, 123.
Description of special objects, 125-132.
Objects near terminator, 133.
Occultation of Stars, 135.
Visibility of new and old Moon, 136.

Moonlight and planetary definition, 187.

Motion of light, 190.

Motion of Stars in the line of sight, 300.

—— of Sun-spots, Proper, 106.

Mounting of Telescopes, 45.

Naked-eye views of Comets, 248.

—— —— of Jupiter in daylight, 170.

—— —— of Jupiter’s satellites, 188.

—— —— of Mercury, 139.

—— —— of Sun-spots, 89.

—— —— of Uranus, 217.

—— —— of Venus in transit, 105.

—— —— of Vesta, 168.

Names of the Stars, Learning the, 287.

Nasmyth and Carpenter describe Plato, 126.

Nasmyth’s Telescopes, 16.

—— “Willow-leaves,” 101.

Nature of Cometary apparitions, 229.

—— of the red spot on Jupiter, 177.

NEBULÆ AND CLUSTERS OF STARS, 324.
Distinction, 324.
Large number visible, 324.
Varieties of form and grouping, 325.
Distribution in R.A., 326.
Early observations, 326.
Variable Nebulæ, 327.
Nebulous Stars, 330.
The Magellanic Clouds, 331.
Double Nebulæ, 332.
Real dimensions of Nebulæ and Clusters, 332.
Round Nebulæ and Clusters, 332.
Description of Nebulæ and Clusters, 333.
Great Nebula in Andromeda, 334.
—— —— in Orion, 334.
Planetary Nebulæ, 334.
Spiral Nebula, 335.
Crab Nebula in Taurus, 336.
Dumb-bell Nebula, 337.
Ring Nebula in Lyra, 337.
Elliptical Nebulæ, 338.
Globular Clusters, 338.
Further observations, 339.
Discovery of new Nebulæ, 341.
New Nebulæ discovered at Bristol, 342.
List of Clusters of Stars, 343.
—— of globular Clusters, 344.
—— of Nebulæ, 345.

Nebulous Stars, 330.

Neison, Lunar observations, 128, 129.

NEPTUNE, Discovery of, 221.
Observations in 1795, 222.
Period &c., 223.
Observations, 223.
Supposed ring, 223.
The satellite, 223.

New or temporary Stars, 312.

Newton, 128.

Newton, Sir Isaac, Experiments on Colours, 9.

——, His reflecting-telescope, 11.

——, On mountainous sites for telescopes, 347.

Noble, Occultation of Jupiter, 186.

——, Occultation of Saturn, 210.

—— on observations of Mercury and Venus, 348.

Nomenclature of Comets, 246.

—— of Lunar formations, 123.

—— of Mars, 158.

—— of Meteor-systems, 271.

Number of Comets visible, Large, 228.

—— of Nebulæ and Star-clusters, 324.

—— of Planetoids, 167.

—— of Stars, 293.

Observations of Neptune, 223.

—— required of the Sun, 97.

—— —— of the Moon, 116.

—— —— of Mercury, 143.

—— —— of Venus, 152.

—— —— of Mars, 162.

—— —— of Jupiter, 183.

—— —— of Saturn, 205.

—— —— of Uranus, 219.

—— —— of Comets, 243.

—— —— of Meteors, 279.

—— —— of Stars, 320.

—— —— of Nebulæ, 339.

——, Solar, 88.

Observatories, 64.

Observer’s aims, 42.

Observing, Open-air, 75.

Observing-seats, 53.

Occultations of Jupiter, 185.

—— of Jupiter’s satellites, 189, 190.

—— of Mars, 166.

—— of Mercury, 144.

—— of Regulus by Venus, 154.

—— of Saturn, 209.

—— of Star by Jupiter, 193.

—— of Venus, 153.

—— of Vesta, 169.

Olbers discovers Pallas and Vesta, 167.

——, His Comet of 1815, 235, 241.

——, Observer of Comets, 250.

Open-air observing, 75.

Opera-glass, 61.

Orbits of Comets, Differences in, 230.

Orion, Great Nebula in, 334.

——, The constellation, 289.

Orionids, 275.

Orionis β, 307.

—— θ, 318.

—— σ, 318.

Outbursts of Faculæ, 108.

Palisa, Discoverer of Planetoids, 167.

Palitzch, Discoverer of Halley’s Comet, 236.

Pallas, 168.

Parabola, 230.

Past and future work, 84.

Periodical Comets, 234.

—— ——, Grouping of, 241.

Periodicity of Jupiter’s markings, 184.

—— of Sun-spots, 100.

Perrotin observes the belts on Uranus, 218.

—— —— the canals on Mars, 27, 160.

—— on work with a 30-inch refractor, 347.

Perry on drawing Sun-spots, 93.

—— observes veiled Sun-spots, 110.

Persei β (Algol), 310.

—— χ, 317.

Perseids, 275.

——, Their shifting radiant-point, 283.

Perseverance, 79.

Petavius, 128.

Peters, Discoverer of Planetoids, 167.

Phase, Epochs of similar, 117.

—— of Jupiter, 172.

—— of Mars, 156.

Phases of Mercury, 139.

—— of Venus, 147.

Phobos, Inner Satellite of Mars, 165.

Photography, 82.

Photometric measures of Starlight, 295.

Physical aspects of Comets, 244.

—— changes on the Moon, 120.

Pickering on the canals of Mars, 348.

Planetary bodies on the Sun, 105.

—— conjunctions, 225.

—— Nebula, 334.

Planetoid, The 308th, 349.

PLANETOIDS, Number of, 167.
History of their discovery, 167.
Occultation of Vesta, 167.
Dimensions and brightness, 168.

Plato, 125.

Polaris, 308.

Pons, Discoverer of many Comets, 250.

Pons’s Comet of 1812, 241, 242, 245.

Pons-Winnecke’s Comet, 240.

Powers, Method of determining, 49.

——, Overstating, 49.

——, Requisite magnifying, 48.

Præsepe, 317.

Preparation of the observer, 66.

Princeton refractor, Performance of, 26.

Prizes for Cometary discoveries, 258.

Proctor on Amateur observers, 163.

—— on Sun-ejected Meteors, 349.

Projection of satellites of Jupiter, 190.

—— of Stars on the Moon, 135.

Prominences, Solar, 111.

Proper motion of spots on Jupiter, 173.

—— —— of Stars, 299.

—— —— of Sun-spots, 106.

Publications, Astronomical, 83.

Pulkowa, The 30-inch refractor at, 27.

Quadrantids, 274.

Radiation of Meteors, 262.

Ramsden’s positive eyepiece, 47.

Ranyard, Absorption of light by object-glasses, 37.

Recording Meteor-tracks, 280.

Records, 72.

Recurrent disturbances on the Sun, 110.

—— forms on the Sun, 111.

Red spot on Jupiter, Appearance of, 173;
Rotation of, 175;
Nature of, 177.

Refracting-lenses or burning-glasses, 3.

Refracting-telescope, 12.

Refractors and Reflectors, 39.

Rheita, Valley near, 131.

Rigel, 307.

Ring nebula in Lyra, 337.

—— of Neptune, Supposed, 223.

—— of Saturn, Division in the outer, 201.

—— ——, The Crape, 202.

Rings of Saturn, 201.

—— ——, Aspect of the, 204.

—— ——, Eccentric position of the, 204.

—— ——, Thickness, 205.

Roberts’s photographs of the Nebula in Andromeda, 334, 351.

—— —— of Nebulæ in Ursa Major, 338.

Rosse, Lord, Large reflecting-telescopes, 14;
Their performance, 21.

Rotation of Comets, Visible evidences of, 246.

—— of Jupiter, 176, 348.

—— of Mars, 161, 348.

—— of Mercury, 142.

—— of Saturn, 199.

—— of the Sun, 103.

—— of Uranus, 217.

—— of Venus, 149.

Round Nebulæ and Clusters, 332.

Safarik on Telescopic Meteors, 273.

Saros, The, 99.

Satellite of Neptune, 223.

—— of Venus, Alleged, 152.

Satellites of Jupiter, 187.

—— of Mars, 164.

—— of Saturn, 211.

—— of Uranus, 220.

SATURN, 195.
Apparent lustre, 195.
Period &c., 196.
“Square-shouldered” aspect, 196.
Early observations, 197.
His belts and spots, 199.
Rotation-period, 199.
The Rings, 201.
Divisions in outer ring, 201.
Crape-ring, 202.
Discordant observations, 204.
Eccentric position of rings, 204.
Aspect of the rings, 204.
Further observations, 205.
Occultations of Saturn, 209.
The Satellites, 211.
Transits of shadow of Titan, 213.
Occultations of Stars by Saturn, 214.

Scheiner’s early observations of Sun-spots, 89.

Schiaparelli, Observations of Mars, 159.

——, Observations of Mercury, 141.

—— associates Comets and Meteors, 264.

Schmidt announces change in a lunar crater, 121.

——, Discoverer of a new Star, 315.

Schröter’s observations of Mercury, 142.

—— —— of Saturn, 200.

—— —— of Venus, 148.

Scintillation of Stars, 297.

Scorpii α, 309.

Shadows cast by Faculæ, 109.

Short’s reflectors, 12.

Showers of Meteors, 274.

Sidereal work, 286.

Silver-on-glass films, Duration of, 60.

Sirius, 300, 307.

Small telescopes, 31.

—— —— and Mars, 160.

—— —— and Solar work, 90.

Solar Eclipse of Aug. 19, 1887, 98.

—— Eclipses visible in England, 98.

—— observations, 88.

—— Prominences, 111.

Southern Comets, Large, 233, 234.

Spiral Nebula, 335.

Spitaler’s Comet of 1890, 349.

“Square-shouldered” aspect of Saturn, 196.

Star-disks, 298.

Stars, Nebulous, 330.

——, Occultation of, 135.

—— visible through Comets, 246.

STARS, THE, 286.
Sidereal work, 286.
Greek Alphabet, 287.
Learning the names of the Stars, 287.
The constellation Orion, 289.
The constellation Figures, 290.
Means of Measurement, 290.
Dividing power, 292.
Number of Stars, 293.
Magnitudes, 294.
The Milky Way, 295.
Scintillation of Stars, 297.
Star-disks, 298.
Distance of the Stars, 299.
Proper motions of Stars, 299.
Double Stars and binary systems, 300.
List of Double Stars, 302-5.
α Canis Majoris, 307.
β Orionis, 307.
α Lyræ, 308.
α Ursæ Minoris, 308.
α Scorpii, 309.
Variable Stars, 309.
ο Ceti and β Persei, 310.
List of Variable Stars, 311.
New or temporary Stars, 312.
Description of temporary Stars, 312.
Star-colours, 315.
Groups of Stars, 316.
Coma Berenices, 317.
The Pleiades, 317.
Præsepe, 317.
χ Persei, 317.
κ Crucis, 318.
ζ Ursæ Majoris, 318.
σ Orionis, 318.
θ Orionis, 318.
Further Observations, 320.

“Stops,” Utility of, 58.

Storms, Meteor, 271.

Straight Wall, 130, 131.

Streak seen at Jask, Meteor-, 278.

Structure of Sun-spots, Crateriform, 101.

SUN, THE: Diameter and Distance, 87.
Solar observations, 88.
Spots on the Sun, 88.
Early observations, 88.
Small telescopes and solar work, 90.
Tinted glass, 91.
Solar diagonal, 92.
Drawing Sun-spots, 93.
Ascertaining dimensions, 94.
Sun-spot of June 19, 1889, 95.
Eclipses of the Sun, 97.
Periodicity of Spots, 100.
Crateriform Structure, 101.
“Willow Leaves,” 101.
Rotation of the Sun, 103.
Determining the Period, 104.
Planetary bodies in transit, 105.
Proper motion of Sun-spots, 106.
Rise and decay of spots, 106.
Black nuclei in the Umbræ, 106.
Bright objects near Sun, 107.
Cyclonic Action, 108.
Sudden outbursts of Faculæ, 108.
Shadows cast by Faculæ, 109.
Veiled Spots, 110.
Recurrent disturbances, 110.
Recurrent forms, 111.
Exceptional position of Spots, 111.
The Solar prominences, 111.

Sun-spots, 88, 347.

Superstitious ideas on Comets, 227.

Surface configuration of Mars, 156.

—— markings on Mercury, 142.

—— —— on Venus, 147.

Sweeping for Comets, 249.

—— for Nebulæ, 340.

Swift, Discoverer of Comets, 252.

——, —— of Nebulæ, 339.

Tails of Comets, 244.

Tarrant on Double Stars, 291.

Telescope, Invention and Development, 1.

Telescopes, Cheapness and increasing number of, 57.

——, Choice of, 38.

——, Large and small, 20.

——, Mounting of, 45.

——, Testing, 43.

Telescopic Comets, 256.

—— Meteors, 272.

—— Work, Attractions of, 85.

Tempel’s Comets, 241.

—— Nebula in the Pleiades, 329.

—— observation of Aristarchus, 120.

Temporary Stars, 312.

Tenuity of Comets, 229.

Terby’s White Spot on Saturn’s rings, 203.

Terminator, Moon’s age and Objects near, 133.

Testing Telescopes, 43.

Test-objects, 55.

Theophilus, 128.

Thornthwaite, Method of Solar observation, 92.

Tinted glass for Solar observation, 91.

Titan, Transit of, 213.

Total Eclipses of the Moon, 118.

—— —— of the Sun, 99.

Transits of Intra-Mercurial Planets, 105, 137.

—— of Jupiter’s satellites and their shadows, 189, 191.

—— of Mercury, 143.

—— of Venus, 153.

Trans-Neptunian planet, 224.

Tupman, Method of tabulating Meteors, 282.

——, Remarks on a Fireball, 267.

Tuttle’s Comet, 241.

Twilight on Venus, 151.

Twinkling of the Stars, 297.

Tycho, 127.

URANUS, Discovery, 215.
Mistaken for a Comet, 215.
True character revealed, 216.
Period &c., 217.
Observations, 217.
His belts, 218.
Further observations, 219.
The satellites, 220.

Ursæ Majoris ζ, 318.

Ursæ Minoris α, 308.

Utility of “stops,” 58.

Variable Nebulæ, 327, 351.

—— Stars, 309.

—— ——, List of, 311.

—— ——, Observations of, 321.

Variations in the light of Comets, 245.

Varieties of form and grouping in Nebulæ and Star-clusters, 325.

—— of Meteors, 276.

Vega, 301, 308.

Veiled Sun-spots, 110.

VENUS, Beauty and brilliancy of, 145.
Period &c., 146.
As a telescopic object, 146.
Surface-markings, 147.
Rotation-period, 149.
Faintness of the markings, 150.
Twilight, 151.
Alleged satellite, 152.
Further observations, 152.
Transits, 153.
Occultations, 153.

Vesta, 168;
Occultation of, 169.

Visibility of Mercury, 138.

Vision, 70.

Vulcan, Supposed planet, 137, 348.

Wargentin describes a Lunar Eclipse, 119.

Warner’s Comet-Prizes, 259.

Washington Refractor, The great, 25, 36.

Weather and Comet-seeking, English, 251.

Webb, Lunar observations, 127, 130, 131.

——, Markings on Mercury, 143.

Williams, Observations of canals of Mars, 160.

——, —— of Jupiter, 175, 177.

——, —— of Jupiter’s satellites, 191.

——, —— of Plato, 126.

“Willow-Leaves,” The Solar, 101.

Wind, Its influence on definition, 69.

With of Hereford, Maker of glass specula, 15.

Wolf on large and small Telescopes, 25, 35.

Working-lists, 68.

Young, Performance of 23-inch refractor, 26.

—— observes belts on Uranus, 217.

—— on the successes of small instruments, 34.

PRINTED BY TAYLOR AND FRANCIS,

RED LION COURT, FLEET STREET.