CORNELL UNIVERSITY LIBRARY BEQUEST OF STEWART HENRY BURNHAM 1943 arV11651 Uranograph' Cornell University Library 111 3 1924 031 323 771 A Cornell University y Library The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924031323771 URANOGRAPHY UEANOGEAPHY A BKIEF DESCRIPTION OF THE CONSTELLATIONS VISIBLE IN THE UNITED STATES -STAEr-MAPS, AND LISTS OF OBJECTS OBSERVABLE WITH A SMALL TELESCOPE BY C. A. YOUNG, Ph.D., LL.D. Late Peofessor of Astbonomy is Princeton Univeesity A SUPPLEMENT TO THE AUTHOR'S "ELEMENTS OF ASTRONOMY FOR HIGH SCHOOLS AND ACADEMIES" GINJSr AND COMPANY BOSTON • NEW YORK • CHICAGO • LONDON Entered at Stationers' Hall Copyright, 1889 and 1897, Br CHARLES A. YOIHSTG. All Eights Eesebved. 614.7 tlClie g t ji e titt u m jgregj GINN AND COMPANY- PRO- PRIETORS • BOSTON ■ U.S.A. PEEFACE. This brief description of the constellations was pre- pared, at the suggestion of a number of teachers, as an integral part of the author's "Elements of Astronomy." It has been thought best, however, for various reasons, to put it into such a form that it can be issued separately, and used if desired in connection with the larger " Gen- eral Astronomy," or with any other text-book. Since the Uranography also has to be used more or less in the open air at night, many will probably prefer to have it by itself, so that its use need not involve such an exposure of the rest of the text-book. All references marked Astr. are to the articles of the " Elements of Astronomy." ALPHABETICAL LIST OF THE CONSTELLATIONS DE- SCRIBED OR MENTIONED IN THE URANOGRAPHY. Article Article Andromeda 16 Hydra 38 Anser, see Vulpeciila . . 54 Lacerta . 61 Antinoiis, see Aquila . 56 Leo . 36 Antlia 45 . Leo Minor 37 Aquarius . 63 Lepus 27 Aquila 56 Libra 44 Argo Navis 34 Lupus 45 Aries 19 Lynx 29 Auriga 22 Lyra 52 Bootes 42 Mondceros 32 Camelopardalis . 14 Norma 47 Cancer 35 Ophiuchus . 48, 49 Canes Venatioi . 41 Orion . 24, 25 Canis Major 33 Pegasus . 62 Canis Minor 81 Perseus 21 Capricornus 58 Phcenix . 20 Cassiopeia 9, 10 Pisces 17 Centaurus 45 Piscis Australia. 64 Cepheus . 11 (Pleiades) 23 Cetus 20 Sagitta 55 Coma Berenices 40 Sagittarius 57 Columba . 28 Scorpio . 46, 47 Corona Borealis 43 Sculptor . 20 Corvus 38 Serpens . 48,49 Crater 38 Serpentarius, see Oph Luchus 48, 49 Cygnus 53 Sextans . 37 Delphinus . 59 Taurus 23 Draco 12,13 Taurus Poniatoyii 48 Equuleus . 60 Triangulum 18 Erfdanus . 26 Ursa Major . 5-7 Gemini 30 Ursa Minor 8 Grus . . . . 64 Virgo 39 EercTjles . . . . 50, 51 Vulpeciila . 54 471 TJEAITOGKAPHY. THE GEEEK ALPHABET. Letters. Name. Letters. Name. Letters. Name. A, a, Alpha. I, t, Iota. 'P,P,S Eho. B,/3, Beta. K, K, Kappa. X 0-, s , Sigma. T>y> Gamma. A, X, Lambda. T,r, Tau. A, 8, Delta. M,,., Mu. Y,v, Upsilon E, ., Epsilon. N, V, Nu. *, <^, Phi. z, i, Zeta. n,i, Xi. X, X. Chi. H,,, Eta. 0,0, Omicron. %^, Psi. ©, 0, .? , Theta. n,7r, Pi. n, 0), Omega. 472 URANOGEAPHY, A Description of the Constellations. 1. A general knowledge of the constellations sufficient to enable one to recognize readily the more conspicuous stars and their principal configurations, is a very desirable accomplish- ment, and not difficult to attain. It requires of course the actual study of the sky for a number of evenings in different parts of the year ; and the study of the sky itself must be supplemented by continual reference to a celestial globe or star-map, in order to identify the stars observed and fix their designations. A well-made globe of sufficient size is the best possible help, because it represents things wholly without dis- tortion, and is easily "rectified" (Astr. 628^) for any given hour, so that the stars will all be found in the proper quarter of the (artificial) heavens, and in their true relations. But a globe is clumsy, inconvenient out of doors, and liable to dam- age ; and a good star-map properly used will be found but little inferior in efficiency, and much more manageable. 2. Star-Maps. — Such maps are made on various systems, each presenting its own advantages. None are without more or less distortion, especially near the margin, though they 1 The references are to the articles in the Author's ' ' Elements of Astron- omy," to which this Uranography is a supplement. 473' 8 TJEANOGRAPHY. [§ 2 differ greatly in this respect. In all of them the heavens are represented as seen from the inside, and not as on the globe, which represents the sky as if seen from the outside; i.e., the top of the map is north, and the east is at the left hand ; so that if the observer faces the south and holds up the map before and above him, the constellations which are near the meridian will be pretty truly represented. 3. We give a series of four small maps which, though hardly on a large enough scale to answer as a satisfactory celestial atlas, are quite sufficient to enable the student to trace out the constellations and identify the principal stars. In the map of the north circumpolar regions (Map I.), the pole is in the centre, and at the circumference the right-ascension hours are numbered in the same direction as the figures upon a watch face; but with 24 hours instead of 12. The parallels of declination are represented by equidistant and concentric circles. On the three other rectangular maps, which show the equatorial belt of the heavens lying between + 50° and — 50° of declination, the parallels of declina- tion are equidistant horizontal lines, while the hour-circles are vertical lines also equidistant, but spaced at a distance which is correct for declination 35°, and not at the equator. This keeps the distortion within reasonable bounds even near the margin of the map, and makes it very easy to lay off the place of any object for which the right ascension and declination are given. The hours of right ascension are indicated on the central hori- zontal line, which is the equator, and at the top of the map are given the names of the months. The word September, for instance, means that the stars which are directly under it upon the map will be near the meridian about nine o'clock in the evening during that month. 4. The maps show all the stars down to the 4J magnitude — all that are easily visible on a moonlight night. A few smaller stars are also inserted, -where they mark some peculiar configuration or point out some interesting telescopic object. So far as practicable, i.e., north of —30° Declination, the magnitudes of Pickering's "Harvard Pho- tometry " are used. The places of the stars are for 1900. 474 § 4] THE CIECTJMPOLAR CONSTELLATIONS. 9 In the designation of clusters and nebulae the letter M. stands for " Messier," who made the first catalogue of 103 such objects in 1784 ; e.g., 97 M. designates No. 97 on that list. A few. objects from Herschel's catalogue are denoted by ^ with a number following. The student or teacher who possesses a telescope is strongly urged to get Webb's "Celestial Objects for Common Telescopes." It is an invaluable accessory. (Longmans, Green & Co., N. Y.) THE CIRCUMPOLAR CONSTELLATIONS. We begin our study of Uranography -witli the constellations which are circumpolar {i.e., within 40° of the north pole), because these are always visible in the United States, and so can be depended on to furnish land (or rather sky) -marks to aid in identifying and tracing out the others. 5. Ursa Major, the Great Bear (Map I.). — Of these cir- cumpolar constellations none is more easily recognizable than Ursa Major. Assuming the time of observation as about eight o'clock in the evening on Sept. 22d (i.e., SC" sidereal time), it will be found below the pole and to the west. Hold the map so that the VIII. is at the bottom, and it will be rightly placed for the time assumed. The familiar Dipper is sloping downward in the northwest, composed of seven stars, all of about the second magnitude ex- cepting 8 (at the junction of the handle to the bowl), which is of the third. The stars a and p are known as the "Pointers," because the line drawn from yS through a, and produced about 30°, passes very near the Pole-star. The dimensions of the Dipper furnish a convenient scale of angular measure. Prom a to /J is 6° ; a to 8 is 10° ; /? to y, 8° ; from a to ?; at the extremity of the Dipper-handle (which is also the Bear's tail) is 26°. 6. The Dipper (known also in England as the "Plough," and as the " Wain," or wagon) comprises but a small part of 475 10 UEAN06BAPHY. L§ «> the whole constellation. The head of the Bear, indicated by a scattered group of small stars, is nearly on the line from 8 thi'ough a, carried on about 15° ; at the time assumed (20'' sid. time), it is almost exactly below the pole. Three of the four paws are marked each by a pair of third or fourth magnitude stars 1^° or 2° apart. The three pairs are nearly equidistant, about 20° apart, and almost on a straight line parallel to the diagonal of the Dipper-bowl from a to y, but some 20° south of it. Just now (20'' sid. time) they are all three very near the horizon for an observer in latitude 40°, but during the spring and summer they can be easily made out. 7. Names' of Principal Stars. — Alioth. MizAK. The little star near it is Alcor, the "rider on his horse." Benetnasch or Alkaid. Double Stars: (1) ^ (Mizar), Mags. 3 and 5; Pos.^ 149°; Dist. 14".5. In looking at this object the tyro will be apt to think that the small star shown by the telescope is identical with Alcor : a very low power eye-piece wUl correct the error. (Astr. Fig. 113.) The large star is itself a "spectroscopic binary" (see Art. 465*). (2) ^, the southern one of the pair which marks the left hind paw. Binary: Mags. 4 and 5; Pos. (1910) (about) 120°, Dist. (about) 3". Position and distance both change rapidly, the period being only 61 years. This was the first binary whose orbit was computed. Clusters and Nebulce: (1) 81 and 82 M., A.R. 9h45'", Dec. 69° 44'. Two nebulse, one pretty bright, about haK a degree apart. (2) 97 M., A.R. Ill" 07", Dec. 55° 43'— 2° south-following p. A planetary nebula. 1 Capitals denote names that are generally used; the others are met with only rarely. 2 The " position angle " of a double star is the angle which the line drawn from the larger star to the smaller one makes with the hour-circle. It is always reckoned from the north completely around through the east, as shown in Fig. A. 47S u. DUBHE. £. 13. Merak. c y. Phecda. 8. Megrez. V- i8] T7ESA MTNOE, THE LESSER BEAK. 11 8. Ursa Minor, the Lesser Bear (Map I.). — The line of the " Pointers " unmistakably marks out the Pole-star (" Polaris " or "Cynosura"), a star of the second magnitude standing alone. It is at the end of the tail of Ursa Minor, or at the extremity of the handle of the " Little Dipper," for in Ursa Minor, also, the seven principal stars form a dipper, though with the handle bent in a different way from that of the other Dipper. Beginning at "Po- laris" a curved line (concave towards Ursa Major) drawn through 8 and £ brings us to ^, where the handle joins the bowl. Two bright stars (second and third magnitude), j3 and y, correspond to the pointers in the larger Dipper, and are known as the "Guardians of the Pole": ^ is called "Kochab." The remaining corner of the bowl is marked by the faint star j; with another still smaller one near it. The Pole lies about 1|^° from the Pole-star, on the line joining it to f UrssB Majoris (at the bend ia the handle of the large Dipper). Telescopic Object. Polaris has a companion of the 9J magnitude, distant 18".6, — visible with a two-inch telescope. 9. Cassiopeia (Map I.). — This constellation lies on the opposite side of the pole from the Dipper at about the same 477 Fig. a. — Measurement of Distance and Fofiition- Angle of a Double Star. 12 UKAUOGBAPHY. [§ ' distance as the "Pointers," and is easily recognized by tlie zigzag, " rail-fence " configuration of the five or six bright stars that mark it. With the help of the rather inconspicuous star K, one can make out of them a pretty good chair with the feet turned away from the pole. But this is wrong. In the recog- nized figures of the constellation the lady sits with feet toivards the pole, and the bright star a is in her bosom, while ^ and the other faint stars south of a, are in her head and uplifted arms : t, on the line from 8 to e produced, is in the foot. The order of the principal stars is easily remembered by the word Bagdei; i.e., P, a, y, 8, e, i. Names of Stars : a (which is slightly variable) is known as Schedir ; j3 is called Caph. Double Stars: (1) rj, Mags. 4-7 J. Large star orange; small one purple. Pos. 170° ±, Dist. 5".5. Binary, with a period of some 200 years. Easily recognized by its position about half-way between a and y, a little off the line. (2) ^|/, A.R. l^ 17"', Dec. 67° 21' ; Triple ; Mags. U, 9 and 9 ; Pos. A to (B-l-C) 106°, Dist. 29"; Pos. B-C 257°, Dist. 2". 9. Found on a line from rj through -y produced three times the distance 17-y: rather difficult for a four-inch telescope. 10. The Sidereal Time determined by the Apparent Position of Cassiopeia. — The line from the Pole-star through Caph or /3 Cassiopeiee (which is the leader of all the bright stars of the constella- tion in their daily motion) is almost exactly parallel to the Equinoc- tial Colure. When, therefore, this star is vertically above the Pole-star it is sidereal noon; it is &^ when it is on the great circle (not the par- allel of altitude) drawn from the Pole-star to the west point of the Horizon ; 12'' when vertically below it ; and 18'' when due east. A little practice will enable one to read the sidereal time from this celes- tial clock with an error not exceeding 15 or 20 minutes. 11. Cepheus (Map I.). — This constellation contains very few bright stars. At the assumed time (20'' sidereal) it is above and west of Cassiopeia, not having quite reached the meridian above the pole. A line carried from a Cassiopeise througli p, and produced 20° (distance a . . . ^ = 6° nearly) 478 § 11] DRACO. 13 will pass very near to a Cephei, a star of the third magnitude, in the king's right shoulder. /3 Cephei is about 8° due north of a, and y about 12° from fi, both also of third magnitude : y is so placed that it is at the obtuse angle of a rather flat isosceles triangle of which ^ Cephei and the Pole-star form the two other corners. Cepheus is represented as sitting behind Cassiopeia (his wife) with his feet upon the tail of the Little Bear, y being in his left knee. His head is marked by a little triangle of fourth magnitude stars, 8, e, and ^, of which S is a remarkable variable with a period of 5^ days (see Astr. Table IV.). There are several other small variables in the same neighbor- hood, but none of them are shown on the map. Names of Stars: a is Alderamin, and /? is Alphirk. Double Stars : (1) j8, Mags. 3 and 8 ; Pos. 251° ; Dist. 14". (2) 8, Mags, larger star 3.7 to 5 (variable), smaller one 7 ; Pos. 192°, Dist. 41" ; Colors, yellow and blue. (3) k, A.R. 201" 13", Deo. 77° 19' ; Mags. 4.5 and 8.5; Pos. 124°; Dist. 7."5; Colors, yellow and blue. 12. Draco (Map I.). — The constellation of Draco is char- acterized by a long, sinuous line of stars, mostly small, extend- ing half-way around the pole and separating the two Bears. A line from 8 Cassiopeise drawn through /3 Cephei and ex- tended about as far again will fall upon the head of Draco, marked by an irregular quadrilateral of stars, two of which are of the 2^ and 3d magnitude. These two bright stars about 4° apart are /S and y ; the latter in its daily revolution passes almost exactly through the zenith of Greenwich, and it was by observations upon it that the aberration of light was discovered (Astr. 125). The nose of Draco is marked by a smaller star, fi, some 5° beyond j3, nearly on the line drawn through it from y. From y we trace the neck of Draco, eastward and downward ' towards the Pole-star until we come to S and e and some smaller stars near them. There the direction of the line is reversed, 1 The description here applies strictly only at 20'' sid. time. 479 14 TJEANOGEAPHY. [§ 12 SO that the body of the monster lies between its own head and the bowl of the Little Dipper, and winds around this bowl until the tip of the creature's tail is reached at the middle of the line between the Pointers and the Pole-star. The constella- tion covers more than 12'' of right ascension. 13. One star deserves special notice: a, a star of the 3|- magnitude which lies half-way between Mizar (^ Urs. Maj.) and the Guards (/3 and y Urs. Min.) ; 4700 years ago it was the Pole-star, within 10' or 15' of the pole, and much nearer than Polaris is at present, or ever will be. It is probable that its brightness has considerably diminished within the last 200 years ; since among the ancient and mediaeval astron- omers it was always reckoned of the second magnitude. Names of Stars: a is Thuban; fi, Alwaid ; and y, Etanin. Double Stars: (1) jn., Mags. 4 and ^■, Pos. 165°; Dist. 2".5. Bi- nary, with a probable period of about 600 years. (2) c, Mags. 4, 8; Pos. 0°.0; Dist. 2".9; yellow and blue. Nebula, A.R. 17" 59°"; Dec. 66° 38 . Planetary, like a star out of focus. This object is almost exactly at the pole of the ecliptic, about midway between 8 and f Draoonis, but a little nearer ([. 14. Camelopardalis (Map I.) This is the only remaining one of the strictly circumpolar constellations — a modern asterism contain- ing no stars above fourth magnitude, and constituted by Hevelius simply to cover the great empty space between Cassiopeia and Perseus on one side, and Ursa Major and Draco on the other. The animal stands on the head and shoulders of Auriga, and his head is between the Pole-star and the tip of the tail of Draco. The two constellations of Perseus (which at 20'' sidereal time is some 20° below Cassiopeia) and of Auriga are partly circumpolar, but on the whole can be more conveniently treated in connection with the equatorial maps. Capella, the brightest star of Auriga, and next to Vega and Arcturus the brightest star in the northern hemisphere, at the time assumed (Sept. 22, 8 p.m.), is a few degrees above the horizon in the N.E. Between it and the nose of Ursa Major is part of the constellation of the Lynx, — a modern asterism made, like Camelopar- dalis, merely to fill a gap. 480 § 15] MILKY WAY IN CIECUMPOLAE REGION. 16 16. Tlie Milky Way in the Circumpolar Region. — The only circumpolar constellations traversed by it are Cassiopeia and Cepheus. It enters the circumpolar region from the constella- tion of Cygnus, -which at 20'' sidereal time is just in the zenith, sweeps down across the head and shoulders of Cepheus, and on through Cassiopeia and Perseus to the northeastern horizon in Auriga. There is one very bright patch a degree or two north of /? Cassiopeise ; and half-way between Cassiopeia and Perseus there is another bright cloud in which is the famous cluster of the "Sword Handle of Perseus" — a beautiful object for even the smallest telescope. 16. Andromeda (Map II.). — Passing now to the equato- rial maps and beginning with the northwestern corner of Map N"o. II., we come first to the constellation of Andromeda, which will be found exactly overhead in our latitudes about 10 o'clock in the middle of November, or at 8 o'clock a month later. Its characteristic configuration is the line of three second-magni- tude stars, a, /8, and y, extending east and north from a, which itself forms the N.E. corner of the so-called " Great Square of Pegasus," and is sometimes lettered as 8 Pegasi. This star may readily be found by extending an imaginary line from Polaris through ^ Cassiopeiee, and producing it about as far again : a is in the head of Andromeda, yS in her waist, and y in the left foot. About half-way from a to /?, a little south of the line, is 8 (of the third magnitude) with tt and e of the fourth magnitude near it. A line drawn northwesterly from P nearly at right angles to the line /3y, will pass through ju at a distance of about 6°, and produced another 6° will strike the "great nebula" (Astr. 470), which forms a little obtuse- angled triangle with v and a sixth-magnitude star known as 32 Andromedse. Andromeda has her mother, Cassiopeia, close by on the north, and at her feet is Perseus, her deliverer, while her Viead rests upon the 481 16 TTBANOGEAPHY. [§ 16 shoulder of Pegasus, the winged horse which brought Perseus to her rescue. To the south, beyond the intervening constellations of Aries and Pisces, Cetus, the sea-monster, who was to have devoured her, stretches his ungainly bulk. Names of Stars, a, Alpheratz ; j3, MiracJi ; y, Almaach. Double Stars. (!) y, Mags. 3, 5; Pos. 62°; Dist. 11"; colors, orange and greenish blue — a beautiful object. The small star is itself double, but at present so close as to be beyond the reach of any but very large instruments (Astr. Fig. 113). (2) ir (2° N. and a little west of 8), Mags. 4, 9 ; Pos. 174° ; Dist. 36" ; white and blue. Nehulce. M. 31 ; the great nebula; visible to naked eye. M. 32; small, round, and bright, is in the same low-power field with 81; south and east of it. 17. Pisces (Map II.). — Immediately south of Andromeda lies Pisces, the first of the zodiacal constellations, though now occupying (in consequence of precession) the sign of Aries. It has not a single conspicuous star, and is notable only as con- taining the vernal equinox, or first of Aries, which lies near the southern boundary of the constellation in a peculiarly star- less region. A line from a Andromedae through y Pegasi con- tinued as far again strikes about 2° east of the equinox. The body of the southern fish lies about 15° south of the middle of the southern side of the great square of Pegasus, and is marked by an irregular polygon of small stars, 5° or 6° in diameter. A long crooked " ribbon " of little stars runs eastward for more than 30°, terminating in a Piscium, called El Rischa, a star of the fourth magnitude 20° south of the head of Aries. From there another line of stars leads up N.W. in the direction of 8 Andromedse to the northern fish, which lies in the vacant space south of /8 Andromedse. Double Stars. (1) a, Mags. 4, 5.5; Pos. 324°; Dist. 3". (2) i/r' (2° S.E. of ri Andromeda — see map), Mags. 4.9, 5; Pos. 160°; Dist. 31". 18. Triangulum (Map II.). — This little constellation, insignifi- cant as it is, is one of Ptolemy's ancient 48. It lies half-way be- tween y Andromedse and the head of Aries, characterized by three stars of the third and fourth magnitudes. 482 § 18] AEIBS. 17 Double Stars. (1) t or 6 (5° nearly due south of ^ Trianguli, and at the obtuse angle of an isosceles triangle of which a and y are the other two corners), Mags. 5, 6.5 ; Pos. 76° ; Dist. 4" ; topaz-yellow and green. 19. Aries (Map II.). — This is the second of the zodiacal constellations (now occupying the sign of Taurus). It is bounded north by Triangulum and Perseus, west by Pisces, south by Cetus, and east by Taurus. The characteristic star-group is that composed of a, j8, y (see map), about 20° due south of y Andromedse : a, a star of the 2^ magnitude is fairly conspicu- ous, forming as it does a large isosceles triangle with jS and y Andromedae. Names of Stars, a, Hamal ; yS, Sheratan ; y, Mesartim. Double Stars. (1) y, Mags. 4.5, 5; Pos. 0°; Dist. 8".8. (This is probably the earliest known double star ; noticed by Hooke in 1664.) (2) e, Mags. 5, 6.5; Pos. 200°; Dist. 1".2. (About one-third of the way from a Arietis towards Aldebaran, t, is 4° beyond it on the same line.) This is probably too difficult for any instrument less than 4 or 4J inches' aperture. (3) tt, Triple; Mags. 5, 8.5, and 11; A-B, Pos. 122°; Dist. 3".l; A-C, Pos. 110°; Dist. 25". (At the southern corner of a nearly isosceles triangle formed with e and t, e being at the obtuse angle.) The star 41 Arietis (3^ mag.), which forms a nearly equilateral tri- angle with a Arietis and y Trianguli, constitutes, with two or three other small stars near it, the constellation of Musca (Borealis), a con- stellation, however, not now generally recognized. 20. Cetus (Map II.). — South of Aries and Pisces lies the huge constellation of Cetus, which backs up into the sky from the southeastern horizon. The head lies some 20° S.E. of a Arietis, marked by an irregular pentagon of stars, each side of which is 5° or 6° long. The southern edge of it is formed by the stars a (2|- mag.) and y (3-|- mag.) : 8 lies nearly south of y. /3, the brightest star of the constellation (2d magnitude), stands alone nearly 40° west and south of a. About half-way 483 18 UEA2JOGEAPHY. [§ 20 from /3 to y the line joining them passes through a character- istic quadrilateral (see map), the N.E. corner of which is com- posed of two fourth-magnitude stars, ^ and x- The remarkable variable o Ceti (Mira) lies almost exactly on the line joining y and 4 a little nearer to y than to f . It is visible to the naked eye for about a month or six weeks every eleven months, when near its maximum. Names of Stars, a, Mbnkar ; y8, DipTida or Deneh Kaitos ; ^, Baten Kaitos; o, Mira. Double Stars. (1) y, Mags. 3.5,7; Pos. 290°; Dist. 2".5; yellow and blue. South of Cetus lies the constellation of Sculptoris Apparatus (usu^ ally known simply as Sculptor), which, however, contains nothing that requires notice here. South of Sculptor, and close to the horizon, even when on the meridian, is Phcenix. It has some bright stars, but none easily observable in the United States. 21. Perseus (Maps I. and II.). — Eeturning now to the northern limit of the map, we come to the constellation of Perseus. Its principal star is a, rather brighter than the standard second magnitude, situated very nearly on the pro- longation of the line of the three chief stars of Andromeda. A very characteristic configuration is "the segment of Per- seus" (Map I.), a curved line, formed by 8, a, y, and rj, with some smaller stars, concave towards the northeast, and run- ning along the line of the Milky Way towards Cassiopeia. The remarkable variable star ^8, or Algol (Astr. 453), is situ- ated about 9° south and a little west of a, at the right angle of a right-angled triangle which it forms with «, (Persei) and y Andromedse. Some 8° south and slightly east of 8 is e, and 8° south of £ are ^ and o of the fourth magnitude in the foot of the hero. Algol and a few small stars near it form " Medusa's Head." Names of Stars, a is Marfak, or Algenib ; p is Algol. Double Stars. (1) e, Mags. 3.5, 9; Pos. 10°; Dist. 8".4. (2) ^ 481 § 21] AITEIGA. 19 Quadruple; Mags. 3.5, 10, 11, 12; Pos. A-B, 207°; Dist. 13".2, 83", 121". (3) rj, Mags. 5, 8.5 ; Pos. 300° ; Dist. 28" ; orange and blue. Clusters. (1) # "VI. 33 and 34. Magnificent. Half-way between y Persei and 8 Cassiopeia. (2) M. 34; A.R. 2'' 34"; Dec. 42° 11'; coarse, with a pretty double star (eighth mag.) included. 32. Auriga (Maps I. and II.). — Proceeding east from Per- seus we come to Auriga, instantly recognized by the bright yellow star Capella (the Goat) and her attendant Hoedi (or Kids). Capella, u. Aurigae, according to Pickering, is precisely of the same brightness as Vega (Mag. = 0.2), both of them being about 3- of a magnitude fainter than Arcturus, but dis- tinctly brighter than any other stars visible in our latitudes except Sirius itself. About 10° east of Capella is /3 Aurigae of the second magnitude, and 8° south of j8 is 5 of the third magnitude; 8 Aurigse is 10° north of j8 in the cireumpolar region, e, ^, and 7], 4° or 5° S.W. of o, are the "Kids." Names of Stars, a, Capella ; j3, Menkalinan. Double Stars. (1) o), Mags. 5, 9; Pos. 353°; Dist. 7"; white, light blue. ^ is a spectroscopic double (see Art. 465*). Clusters. (1) M. 37; A.R. 5" 44"; Dec. 32° 31' (on the line from Aurigae to ^ Tauri, one-third of the way from 6). Pine for small instrument. (2) M. 38; A.R. 5" 21-°; Dec. 35° 47'. Nearly at the middle of the line from to a. (3) M. 36 ; A.R. 5" 28" ; Dec. 34° 3'. One-thh-d of the way from M. 38 to M. 37. 23. Taurus (Map II.).— This, the third of the zodiacal constellations, is bounded north by Perseus and Auriga, west by Aries, south by Eridanus and Orion, and east by Orion and Gemini. It is unmistakably characterized by the Pleiades, and by the V-shaped group of the Hyades which forms the face of the bull, with the red Aldbbaean (a Tauri) blazing in the creature's eye, as he charges down upon Orion. His horns reach out towards Gemini and Auriga, and are tipped with the second and third magnitude stars (3 and ^. As in the case of Pegasus, only the head and shoulders appear in the constella- 4a5 20 tTRAKOGKAPHY. t§ 23 tion. Six of the Pleiades are easily visible, and on a dark night a fairly good eye wDl count nine (see Astr. 469). With a 3-inch telescope about 100 stars are visible in the cluster. In the Hyades the pretty naked-eye double 0^, O^, is worth noting. Names of Stars, a, Aldebaean ; y8, El Nath ; rj (the brightest of the Pleiades), Alcyone. For the names of the other Pleiades, see the figure in Art. 469 of the Astronomy. Double Stars. (1) a has a small, distant companion, 12th magni- tude ; Pos. 36° ; Dist. 1' 48". It has also a second companion much nearer and more minute, but far beyond the reach of ordinary tele- scopes. (2) T, Mags. 5 and 8 ; Pos. 210° ; Dist. 62 " ; white and violet. Found by drawing a line from y (at the point of the V of the Hyades) through t, and producing it as far again. Nebula. M. 1; A.R. 5" 27°'; Dec. 21° 56', about 1° west and a little north of ^. Often mistaken for a comet. The so-caUed "Crab Nebula." 24. Orion (not O'-ri-on) (Map II.). — On the whole this is the finest constellation in the heavens. As he stands facing the bull his shoulders are marked by the two bright stars, u. and y, the former of which in color and brightness closely matches Aldebaran. In his left hand he holds up the lion skin, indicated by the curved line of little stars between y and the Hyades. The top of the club, which he brandishes in his right hand, lies between ^ Tauri and fj. and rj Geminorum. His head is marked by a little triangle of stars of which X is the chief. His belt consists of three stars of the second magni- tude pointing obliquely downward towards Sirius. It is very nearly 3° in length, with the stars in it equidistant like a measuring-rod, so that it is known in England as the "Ell and Yard." From the belt hangs the sword, composed of three smaller stars lying more nearly north and south : the middle one of them is the multiple 6 in the great nebula, fi Orionis, or EiGBL, a magnificent white star, is in the left foot, and k is in the right knee. Orion has no right foot, or if he has, it is 486 § 24] BEIDANUS. 21 hidden beMnd Lepus. The quadrilateral a, y, ^k, with the diagonal belt 8, e, t,, once learned can never be mistaken for anything else in the heavens. 25. Names of Stars, a, Betelgeuse; ^, Rigel; y, Bellatrix; K, Saiph; 8, Mintaka ; e, Alnilam;^, Alnitak. Double Stars. In these Orion is remarkably rich. (1) /3 (Rigel), Mags. 1 and 9; Pos. 200°; Dist. 9".5; both white, — a beautiful and easy object. (2) 8 (the westernmost star in the belt), Mags. 2.5 and 7; Pos. 0; Dist. 53". (3) f, Triple; Mags. 2.5, 6.5, 10; A-B, Pos. 155°, Dist. 2".4; A-C, Pos. 9°, Dist. 59". (4) i, Triple; Mags. 3.5, 8.5, 11 ; A-B, Pos. 142°, Dist. 11".5 ; A-C, Pos. 103°, Dist. 49". (This is the lowest star in the sword, just below the nebula.) (5) $, Multiple, the trapezium in the nebula. Four stars are easily seen by smaU telescopes (Astr. Fig. 113). (6) o-, Triple; Mags. 4, 8, 7; A-B, Pos. 84°, Dist. 12".5; A-C, Pos. 61°, Dist. 42" (1^° S.W. of 0- Nebula. M. 42 ; attached to the multiple star 6. The nebula of all the heavens; by far the finest known, though in a small telescope wanting much of the beauty brought out by a larger one. 26. Eridanus (Map II.). — This constellation lies south of Taurus, in the space between Cetus and Orion, and extends far below the southern horizon. Its brightest star a (Acheenae) is never visible in the United States. Starting with ft of the third magnitude, about 3° north and a little west of Rigel (/8 Orionis), one can follow a sinuous line of stars, some of them of the third and fourth magnitudes, westward about 30° to the paws of Cetus, 10° south of u, Ceti ; there the stream turns at right angles southwards for 10°, then southeast for about 20°, and finally southwestward to the hori- zon. One could succeed in fully tracing it out, however, only by help of a map on a larger scale than the one we are able to present. Names of Stars. P, Cursa; y, ZauracJc. Double Stars. (1) 82; A.R. 3" 48"°, Deo. S. 3° 19'; Mags. 5, 7; Pos. 347°; Dist. 6".6; yellow, blue; very fine. (2) o^, Triple; A.R, 487 22 UEANOGRAPHY. [§ 26 4" 10"; Dec.^. 7° 50'; Mags. 5, 10, 10; Pos. A, (^ + ^\ 108°; Dist. 83" ; Pos. B-C, 110°, Dist. 4" ; very pretty. 27. lepus (Map II.). — This little constellation (one of the ancient 48) lies just south of Orion, occupying a space of some 15° square. Its characteristic configuration is a quadrilateral of third and fourth magnitude stars, with sides from 3° to 5° long, 10° south of K Orionis, and 15° west and a little south of Sirius. Double Stars. (1) y (the S.E. corner of the quadrilateral) is a toarse double. Mags. 4, 6.5 ; Pos. 850° ; Dist. 93". (2) k (5J° south of Rigel), Mags. 5 and 9 ; Pos. 0°; Dist. 3"./. 28. Columba (BToah's Dove) (Map II.). — This is next south of Lepus : too far south to be well seen in the Northern States. Its prin- cipal star, a, or Phact, of the 2J magnitude, is readily found by draw- ing a line from Procyon to Sirius, and prolonging it nearly the same distance. And in passing we may note that a similar line drawn from a Orionis through Sirius and produced, will strike near ^ Argus, or " Naos," a star about as bright as Phact, — the two lines which inter- sect at Sirius making the so-called "Egyptian X." 29. Lynx (Map I., II., and III.). — Returning now to the north- ern limit of the map, we find the modern constellation of the Lynx lying just east of Auriga and enveloping it on the north and in the ciroumpolar region. It contains no stars above the fourth magnitude, and is of no importance except as occupying an otherwise vacant space. Double Stars. (1) 38, or p Lyncis, A.R. 9" 11"; Dec. 37° 21'; Mags. 4, 7.5; Pos. 240°; Dist. 2".9 ; white and lilac. (This is the northern one of a pair of stars which closely resembles the three paii's that mark the paws of Ursa Major. This pair makes nearly an isosceles triangle with the two pairs \ /jl and i k, Ursse Majoris — see map.) 30. Gemini (Map II.). — This is the fourth of the zodiacal constellations (mostly in the sign of Cancer), containing the summer solstitial point about 2° west and a little north of the star Tj. It lies northeast of Orion and southeast of Auriga, and is sufficiently characterized by the two stars a and j8 (about 4^° apart), -which mark the heads of the twins. The southern 488 § 30] CANIS MINOE. 23 one, yS, or Pollux, is the brighter, but a (Castor) is much the more interestiag, as being double. The feet are marked by the third-magnitude stars y and n, some 10° east of ^ Tauri, and the map shows how the lines that join these to /8 and a respectively mark the places of 8 and e. 17, 2° west of /t, is a variable, and is also double, though as such it is beyond the power of ordinary telescopes. Names, a, Castok; )8, Pollux; y, Alhena ^ /x, Tejat {Post); ■q, Tejat (Prior) ; 8, Wasat; c, Meboula. Double Stars. (1) a, Mags. 2.5, 3 ; Pos. 225°; Disfc. 5".5. Binary; period undetermined, but certainly over 200 years. The larger of the close pair is also a spectroscopic binary, with period of about 3 days (see Art. 465*). There is also a companion of ninth mag., dis- tant about 74"; Pos. 164°. (2) 8, Mags. 3, 8 ; Pos. 203°; Dist. 7"- (3) fjL, Mags. 3, 11 ; Pos. 79°; Dist. 80". Nebulce and Clusters. (1) M. 35 ; A.R. Q^ Ol-" ; Dec'. 24° 21' ; N.W. of 77 at the same distance as that from fi to 17, and on the line from y through 7] produced. The map is not quite right in this respect. (2) ff IV. 45 ; A.R. 7" 22'° ; N. 21° 10'. A nebulous star in a small telescope ; in a large telescope, very peculiar — 2° southeast of 8- 31. Canis Minor (Map II.). — This constellation, just south of Gemini, is suf&ciently characterized by the bright star Pkocton, which is 26° due south of the mid-point between Castor and Pollux, a, /S, and y together form a configuration closely resembling that formed by a, /?, and y Arietis. Pro- cyon, u. Orionis, and Sirius form nearly an equilateral triangle with sides of about 25°. Names, a, Procyon ; ;S, Gomelza. Double Stars. (1) Procyon has a small companion, Dist. 40", Pos. 312°, — too small, however, for anything less than an 8-inch telescope. In 1896 a still smaller companion, like that of Sirius, was found much nearer the large star. (See Art. 464.) (2) (% 1126) (following Procyon 43^, and 2' south, — the brightest of the stars in that field), Mags. 7, 7.5 ; Pos. 145°; Dist. 1".5 ; a good test for a 4-inch glass. 489 24 TTEANOGEAPHT. [§ 32 32. Monoceros (The TTnicorn) (Map II.). — This is one of the new constellations organized by Hevelius to fiU the gap between Gem- ini and Canis Minor on the north, and Argo Navis and Canis Major on the south. It lies just east of Orion. It has no conspicuous stars, but is traversed by a brilliant portion of the Milky Way. The u. (fourth mag.) of the constellation lies about haK-way between a Orionis and Sirius, a little west of the line joining them. Double Stars. (1) 8, or & (7J° east and 3° south of a Orionis), Mags. 5, 8 ; Pos. 24° ; Dist. 12".9 ; colors, orange and lUac. A fine low-power field. (2) 11 Monocerotis, a fine triple (see Fig. 113 of Astr.), A.R. 6" 24" ; Dec. south 6° 57'; A to B-C, Pos. 130°, Dist. 8"; B-C, Pos. 120°, Dist. 2". 5. The star is very nearly pointed at by a line drawn from ^ Canis Majoris, north through /?, and continued as far again. Clusters. (1) ff VH. 2 ; A.R. 6" 24" ; Dec. N. 5° 2' (visible to the naked eye about 1J° N.E. of 8 Monocerotis described above). A fine cluster for a low power. (2) M. 50 ; A.R. 6" 57" ; Dec. S. 8° 9'. In the MUky Way, on the line from Sirius to Procyon, two-fifths of the distance. 33. Canis Major (Map II.). — This glorious constellation needs no description. Its a is the Dog Star, Sirius, beyond all comparison the brightest in the heavens, and probably one of our nearer neighbors. It is nearly pointed at by the line drawn through the three stars of Orion's belt. /3, at the ex- tremity of the uplifted paw, is of the second magnitude, and so are several of those farther south in the rump and tail of the animal, who sits up watching his master Orion, but with an eye out for Lepus. Names, a, Sirius; y8, Mirzam; y, Muliphen; 8, Wesen; c, Adara. y is said to have disappeared from 1670 to 1690, but at present is not recognized as variable, though much fainter than would be expected from its being lettered as y. Double Stars. (1) Smus itself has a small companion (see Art. 463). (2) ;u (4° ISr.E. of Sirius), Mags. 5, 9.5 ; Pos. 335°; Dist. 3".5. Clusters. (1) M. 41 (4° south of Sirius) ; a fine group with a red star near centre. 490 §3*] AEGO NAVIS. 25 34. Argo Navis (The Ship) (Maps II. and in.). — This is one of the largest, most important, and oldest of the constellations, lying south and east of Canis Major. Many Urauographers now divide it into three, Puppis, Vela, and Carina. Its brightest star, u, Argus, Canopus, ranks next to Sirius, but is not visible anywhere north of the parallel of 38°. The constellation, huge as it is, is only a lialf one, like Pegasus and Taurus, — only the stern of a vessel, with mast, sail, and oars ; the stem being wanting. In the part of the constellation covered by our maps the most conspicuous stars lie east and southeast of Canis Major. We have already mentioned ^, or Naos (Art. 28), at the southeast extremity of the " Egyptian X " ; and about 8° south and a little east of it is y, nearly of the second magnitude. Clusters. One or two clusters are accessible in our latitudes. (1) (W VIII. 38), A.E. T" SI"-; Dec. S. 14° 12'. Pointed at by the line from j3 Can. Maj. through Sirius, continued 2 J times as far. Visible to naked eye; rather coarse. (2) M. 46; a little more than 1° east and south of the preceding. (3) M. 93, A.K. 7" 39-"; Dec. S. 23° 34'; about 2° N.W. of ^ Argus. 35. Cancer (Maps II. and III.). — This is the fifth of the zodiacal constellations, bounded north by Lynx and Leo Minor, south by the head of Hydra, west by Gemini and Canis Minor, and east by Leo. It does not contain a single conspicuous star, but is easily recognizable from its position, and in a dark night by the nebulous cloud known as "Prsesepe," or the "Manger," with the two stars y and S near it, — the so-called "Aselli," or "Donkeys." Preesepe (sometimes also called the "Beehive") is really a coarse cluster of seventh and eighth magnitude stars, resolvable by an opera-glass. The line from Castor through Pollux, produced about 12°, passes near enough to it to serve as a pointer, a, of the fourth magnitude, is on the line drawn from Preesepe through 8 (the southern Asellus), produced about 7°; /8 may be recognized by drawing a line from y (the northern Asellus) through Prsesepe, and continu- ing it about 12°. Double Stars. (1) i, Mags. 4, 6.5 ; Pos. 308° ; Dist. 30" ; orange and blue ; nearly due north of y, distance twice that between the Aselli. 491 26 TTKANOGRAPHY. [§ ^5 (2) £,, Triple (see Astr. Fig. 113) ; A-B, Mags. 6 and 7, Pos. (1905) 346°, Dist. 1"; in rapid motion; period about 60 years. A-C, Pos. (1905) 110°, Dist. 5" ; also in motion, but period unknown and much longer. Easily found by a line from a Gem. through P, produced two and a half times as far. 36. leo (Map III.). — East of Cancer lies the noble con- stellation of Leo, which adorns the eyening sky in March and April ; it is the sixth of the zodiacal constellations, now occu- pying the sign of Virgo. Its leading star Regulus, or " Cor lieonis," is of the first magnitude, and two others, j8 and y, are of the second, a, y, 8, and j8 form a conspicuous irregular quadrilateral (see map), the line from Eegulus to Denebola being 26° long. Another characteristic configuration is "The Sickle," of which a, 17 is the handle, and the curved line -q, y, ^, IX,, and e is the blade, the cutting edge being turned towards Cancer. The " radiant " of the !N"ovember meteors lies between i, and c. Names, a, Regultjs ; /B, Denebola ; y, Algeiba ; 8, Zosma. Double Stars. (1) y, Mags. 2, 3.5; Pos. 116°; Dist. 3".4; binary; period about 400 years. (2) i, Mags. 4 and 7 ; Pos. 65° ; Dist. 2".5 ; yellow and bluish ; easily recognized by aid of the map. (3) 54, Mags. 4.5, 7; Pos. 103°; Dist. 6".2. Found by producing the line from yS through 8 half its length. 37. Leo Minor and Sextans (Map III.).— ieo Minor is an insignificant modern constellation composed of a few small stars north of Leo, between it and the hind feet of Ursa Major. It contains nothing deserving special notice. A similar remark holds as to Sex- tans even more emphatically. 38. Hydra (Map III.). — This constellation, with its riders Crater and Corvus, is a large and important one, though not very brilliant. The head is marked by a group of five or six fourth and fifth magnitude stars just 16° south of Prsesepe. A curving line of small stars leads down southeast to a, " Cor Hydrce" a small second or bright third magnitude star stand* 492 § 38] VIRGO. 27 ing very much alone. From there, as the map shows, an irregular line of fourth-magnitude stars running far south and then east, almost to the boundary of Scorpio, marks the crear ture's body and tail, the whole covering almost six hours of right ascension, and very nearly 90° of the sky. About the middle of his length, and just below the hind feet of Leo (30° due south from Denebola), we find the little constellation of Crater; and just east of it the still smaller but much more conspicuous one of Oorvus, with two second-magnitude stars in it, and four of the third and fourth magnitudes. It is well marked by a characteristic quadrilateral (see map), with S and Tj together at its northeast corner. The order of the letters differs widely from that of brightness in this constellation, suggesting that changes may have occurred. Names, a Hydrse, Alphaed or Cor Hydrce; a Crateris, Alkes; a Corvi, Alchiha ; 8 Corvi, Algores. Double Stars. (1) e Hydrse (the northernmost one of the group that marks the head), Mags. 4, 8; Pos. 220°; Dist. 3".5 ; yellow and purple. (2) 8 Corvi, Mags. 3, 8; Pos. 210°; Dist. 24"; yellow and purple. (3) Nehula, fl[ IV. 27, A.R. 10" IQ"-; Dec. S. 18° 2' (3° S. and J° W. of fi. — see map). Bright planetary nebula, about as large as Jupiter. 39. Virgo (Map III.). — East and south of Leo lies Virgo, the seventh zodiacal constellation, bounded on the north by Bootes and Coma Berenices, on the east by Bootes and Libra, and on the south by Corvus and Hydra. Its a, Spica Vir- ginis, is of the 1-|- magnitude and, standing rather alone 10° south of the celestial equator, is easily recognized as the southern apex of a nearly equilateral triangle which it forms with Denebola {ji Leonis) to the northwest, and Arcturus northeast of it. /3 Virginis of the third magnitude is 14° due south of Denebola. A line drawn eastward and a little south from p (third magnitude) and then carried on, curving north- ward, passes successively (see map) through rj, y, 8, and e, 493 28 UEANOGEAPHY. [§ 39 of the third magnitude (notice the word formed by the letters Begde, like Bagdei in Cassiopeia, Art. 9). lies nearly mid- way between a and 8. There are also a number of other fourth- magnitude stars. Names, a, Spica and Azimech ; /3, Zavijava ; e, Vindemiatrix. Double Stars. (1) y, (Binary; periSd 185 years; not quite half-way from Spica to Denebola, and a little west of the line), Mags. 3, 3; Pos. (1905) 328°; Dist. 6".2; very easy and fine (Astr. Fig. 113). (2) & (two-flfths of the way from Spica towards 8), Triple; Mags. A 4.5, B 9, C 10; Pos. A-B, 345°, Dist. 7"; A-C, Pos. 295°, Dist. 65". (3) o (one-third of the way from Denebola towards y Virginis), Mags. 6 and 8 ; Pos. 228° ; Dist. 3".5. Spica is a spectroscopic binary (Art. 465*). Nehulce. (1) M. 49 ; A.R. 12'" 24°> ; Dec. -f 8° 40'. Forms an equi- lateral triangle with 8 and e. It lies in the remarkable " nebulous " region of Virgo. But most of the nebulse ai-e faint, and observable only with large telescopes. (2) t§ II. 74 and 75 ; A.R. 12" 47" ; Dec. + 11° 53' ; two in one field, 2° west and a little north of e. (3) M. 86 (midway between Denebola and c) ; A.R. 12" 20° ; Dec. -|- 13° 36 . A large telescope shows nearly a dozen nebulse within 2° of this place. 40. Coma Berenices (Map III.). —This little constellation, com- posed of a great number of fifth and sixth magnitude stars, lies 30° north of y and t] Virginis, and about 15° northeast of Denebola. It contains a number of interesting double stars, but they are not easily found without the help of an equatorial mounting and graduated circles. 41. Canes Venatici (The Hunting Dogs.). — These are the dogs with which Bootes is pursuing the Great Bear around the pole : the northern of the two is Asterion, the southern CJiara. Most of the stars are small, but a is of the 2J magnitude, and is easily found by drawing from rj Ursae Majoris (the star in the end of the Dipper-handle) a line to the southwest, perpen- dicular to the line from i; to ^ (Mizar) and about 15° long : it is about one-third of the way from rj Ursse Majoris to 8 Leonis. With Arcturus and Denebola it forms a triangle much like that which they form with Spica. 494 § *1] BOOTES. 29 Names, a is known as Cor Caroli (Charles II. of England). Double Stars. (1) a, or 12 Canum, Mags. 3 and 5; Pos. 227°; Dist. 20". (2) 2 Canum (one-third of the way from a towards 8 Leonis), Mags. 6 and 8 ; Pos. 260° ; Dist. 41 ".3 ; orange, smalt blue. Nebulae. (1) M. 51 ; A.R. 13" 25-° ; Dec. 47° 49' (3° west and some- what south of Benetnasch). A faint double nebula in small tele- scopes; in great ones, the wonderful "Whirlpool Nebula" of Lord Rosse. (2 ) M. 3 ; bright cluster (half a degree north of the line from a Canum to Arcturus, and a little nearer the latter). It is one of the variable-star clusters discovered in 1895 (see Art. 455*). 42. Bootes (Maps III. and I.). — This fine constellation is bounded on the west by Ursa Major, Canes Venatici, Coma Berenices, and Virgo, and on the south by Virgo. It extends more than 60° in declination, from near the equator quite to Draco, where the uplifted hand overlaps the tail of the Bear. Its principal star, Akctueus, is of a ruddy hue, and in bright- ness is excelled only by Sirius among the stars visible in our latitudes. Canopus and a Centauri are reckoned brighter, but they are southern circumpolars. Arcturus is at once recog- nized by its forming with Spica and Denebola the great tri- angle already mentioned (Art. 39). Six degrees west and a little south of it is ij, of the third magnitude, which forms with it, in connection with v, a configuration like that in the head of Aries, e is about 10° northeast of Arcturus, and in the same direction about 10° farther lies S. A pentagon is formed by these two stars along with /3, y, and p. " Bootes " means "the shouter" (or, according to others, "the herds- man "). Names, a, Aecttteus ; P, Nekkar; t, Izar; rj, Muphridi y, Seginus. Double Stars. (1) e, Mags. 3, 6 ; Pos. 325° ; Dist. 3".l ; orange and greenish blue ; very fine. (2) ^ (about 9° southeast from Arcturus, at right angles to the line ae), Mags. 3.5, 4; Pos. 295°; Dist. 0".8; a good test for a 4-inch glass. (3) ir (2|° north of ^), Mags. 4.9, 6; Pos. 101°; Dist. 5".3. (4) f (10° due east from Arcturus, 3° N.E. from tt), Mags. 4.7, 6.6 ; Pos. (1905)176°; Dist. 2".5; yellow and purple. Binary ; period 127 years. 495 80 tTEANOGEAPHY. [§ 43 43. Corona Borealis (Map III.). — This beautiful little con- stellatiou lies 20° northeast of Arcturus, and is at once rec- ognizable as an alinost perfect semicircle composed of half a dozen stars, among which the brightest, a, is of the second magnitude. The extreme northern one is 6; next comes yS, and the rest follow in the /3 a y 8 c t (Bagdei) order, just as in Cassiopeia. Names, a, Gemma, or Alphacca. Double Stars. (1) f (nearly pointed at by £-8 Bootis ; 7° from e), Mags. 5, 6; Pes. 301°; Dist. 6"; white and greenish. (2) rj, rapid binary, at certain times can be split by a 4-inch glass. Mags. 6, 6.5; pointed at by the line from a through /S, 2° beyond /3. The tempo- rary star of 1866 ( Astr. 450) lies 1J° S.E. of c Coronse. 44. Libra (Map III.). — This is the eighth of the zodiacal constellations, and lies east of Virgo, bounded on the south by Centaurus and Lupus, on the east by the upstretched claw of Scorpio, and on the north by Serpens and Virgo. It is incon- spicuous, the most characteristic figure being the trapezoid formed by the lines joining the four stars a, i, y, /3. /?, which is the northernmost of the four, is the brightest (2\ magni- tude), and is about 30° nearly due east from Spica, while a is about 10° southwest of '/3. The remarkable variable 8 Librae is 4° west and a little north from /?. Most of the time it is of the 4|- or fifth magnitude, but runs down nearly two magni- tudes at the minimum. Names, a, Zuben el Genubi; jS, Zuhen el Chnmali. Cluster. M. 5 ; A.R. 15" 12'"; Dec. N. 2° 32'. This is within the boundaries of Serpens, and just a little north and west of the fifth- magnitude star 5 Serpentis. It is a variable-star cluster (Art. 455*). 45. Antlia, Centaunis, and Inpns (Map III.). — These constel- lations lie south of Hydra and Libra. Antlia Pneumatica (the " Air- Pump") is a modern constellation of no importance and hardly recog- nizable by the eye, having only a single star as bright as the 4J mag- 496 § *5] SCORPIO. 31 nitude. Ceniaunis, on the other hand, is an ancient and extensive asterism, containing in its (south) circumpolar portion two stars of the first magnitude : a Centauri stands next after Sirius and Canopus in brightness, and, as far as present knowledge indicates, is our nearest neighbor among the stars. The part of the constellation which be- comes visible in our latitudes is not specially brilliant, though it con- tains several stars of the 2 J and third magnitude in the region that lies south of Corvus and Spica Virginis. A line from e Virginis through Spica, produced a little more than its own length, will strike very near 6, a solitary star of the 2} magnitude in the Centaur's left shoulder, l (third mag.) lies 11° west of 6, and r] (third mag.) 9° southeast ; while 5° or 6" south of the line from Otoi lies a tangle of third-magnitude stars, which, if they were at a higher elevation, would be conspicuous. Centaurus is best seen in May or early in June. Lupus, also one of Ptolemy's constellations, lies due east of Cen- taurus and just south of Libra. It contains a considerable number of third and fourth magnitude stars ; but is too low for any satisfactory study in our own latitudes. It is best seen late in June. These constellations contain numerous objects interesting for a southern observer, but nothing available for our purpose. 46. Scorpio (or Scorpius) (Map III.). — This, the ninth of the zodiacal constellations, and the most brilliant of them, lies southeast of Libra, which in ancient times used to form its claws (Chelce). It is bounded north by Ophiuchus, south by Lupus, Norma, and Ara, and east by Sagittarius. It is recognizable at once on a summer evening by the peculiar con- figuration, like a boy's kite, with a long streaming tail reach- ing far down to the southern horizon. Its principal star, Ajsttaees, is of the first magnitude and fiery red, like the planet Mars. Prom this it gets its name, which, means "the rival of Ares" (Mars). /3 (second magnitude) is in the arch of the kite bow, about 8° or 9° northwest of Antares, while the star which Bayer lettered as y Scorpii is well within Libra, 20° west of Antares. (There is no little discordance and con- fusion among Uranographers as to the boundary between the 497 32 TJBANOGRAPHT. [§ *8 two constellations.) The other principal stars of the constel- lation are easily found on the map ; 8 is 3° southwest of p, while £, 4 V' ^) h '^! ^^<1 ^ follow along in order in the tail of the creature, except that between e and ^ is interposed the double ix. £, 0, and A. are all of the second magnitude, and the others of the third. 47. Names, a, Antakbs ; /3, Akrab. Double Stars. (1) a, Mags. 1 and 7 ; Pos. 270° ; Dist. 3."5 ; fiery red and vivid green. A beautiful object when the state of the air allows it to be well seen. (2) (3, Triple ; Mags. A 2, B 4, CIO ; A-B, Pos. 25°, Dist. 13"; A-C, Pos. 89°, Dist. 0".9. (3) v (2° due east of /3), Quadruple; Mags. A 4, B 5, C 7, D8; A-B, Pos. 7°, Dist. 0".8 ; A-C, Pos. 337°, Dist. 41"; C-D, Pos. 47°, Dist. 2".4. A beautiful object. (4) i Scorpii (8^ due north froni /?), Triple; Mags. A 5, B 5.2, C 7.5 ; A-B, (Binary) Pos. 200°, Dist. 1".4 ; i(A + B) to C, Pos. 65°, Dist. 7".3. /u.^ is a spectroscopic binary (Art. 465*). Clusters. (1) M. 80, A.R. 16" 10" v Dec. S. 22° 42'; haK-way between a and /3; one of the finest clusters known. (2) M. 4, A.R. 16" le™ ; Deo. S. 26° 14' ; 1|° west of a; not so fine as the preceding. Norma lies west of Scorpio, between it and Lupus, while Ara lies due south of r/ and 0- Both are small and of little importance, at least to observers in our latitudes, 48. Ophmchus {or Serpentarius) and Serpens (Map III.).— Ophiuchus means the "serpent-holder." The giant is repre- sented as standing with his feet on Scorpio, and grasping the " serpent," the head of which is just south of Corona Borealis, while the tail extends nearly to Aquila. The two constella- tions therefore are best treated together. The head of Serpens is marked by a group of small stars 20° due east of Arcturus, and 10° south of Corona, fi and y are the two brightest stars in the group, their magnitudes three and a half and four. S lies 6° southwest of /?, and there the serpent's body bends southeast through a and e Serpentis (see map) to S and e Ophi- uchi in the giant's, hand. The line of these five stars carried upwards passes nearly through e Bootis, and downwards 498 § 48] OPHITJCHTTS. 33 through f Ophiuchi. A line crossing this at right angles, nearly midway between c Serpentis and S Ophiuchi, passes through /i Serpentis on the southwest, and X Ophiuchi to the northeast. The lozenge-shaped figure formed by the lines drawn from a Serpentis and ^ Ophiuchi to the two stars last mentioned forms one of the most characteristic configurations of the summer sky. a Ophiuchi (2^ magnitude) is easily recognized in connection with a Herculis, since they stand rather isolated, about 6° apart, on the line drawn from Arcturus through the head of Serpens, and produced as far again, u, Ophiuchi is the eastern and the brighter of the two. It forms with Vega and Altair a nearly equilateral triangle. /3 Ophiuchi lies about 9° southeast of a ; and 5° east and a little south of /8 are five small stars in the Milky Way, forming a V with the point to the south, much like the Hyades of Taurus. They form the head of the now discredited constellation " Poniatowski's Bull" (Taunts Poniatovii), proposed in 1777. 49. Names, a Ophiuchi, Ras Alaghue; /3, Cehalrai; 8, Yed ; X, Marjic: a. Serpentis, UnuTcalhai ; 6, Alya. , Double Stars. (1) X Ophiuchi, Binary ; period, 234 years ; Mags. 4, 6 ; Pos. (1905) 60° ; Dist. 1".2. (2) 70 Ophiuchi (the middle star in the eastern leg of the V of Poniatowski's Bull), Binary; period, 93 years ; Mags. 4.5, 7; Pos. (1905) 180° ; Dist. 2". The position angle changes very rapidly just now, and the star is too close to be resolved by a small instrument. (3) 8 Serpentis, Mags. 4, 5 ; Pos. 185° ; Dist. 3!'.6 ; very pretty. (4) Serpentis, Mags. 4, 4.5; Pos. 104°; Dist. 21". (5) V Serpentis (4° N.E. of tj Ophiuchi), Mags. 4.5, 9 ; Pos. 31°; Dist. 51" ; sea-green and lUac. Clusters. (1) M. 23, A.R. 17" 50"; Dec. S. 19° 0'. Fine low- power field. (2) M. 12, A.R. 16" 41" ; Dec. S. 1° 45'. On the line between p and e Ophiuchi, one-third of the way from e. (3) M. 10, A.R. 16" SI"" ; Dec. S. 3° 56'. On the line between p and f Ophiuchi, two-fifths of the way from ^. (4) ^ VIII. 72, A.R. 18" 22" ; Dec. N. 6° 29'. Pointed at by the eastern leg of the Poniatowski V. 8° from 70 Ophiuchi. 499 84 TJEANOGRAPHY. [§ 50 60. Hercules (Maps I. and III.)- — This noble constellation lies next north of Ophiuchus, and. is bounded on the west by Serpens, Corona, and Bootes, while to the east lie Aquila, Lyra, and Cygnus. On the north is Draco. The hero is represented as resting on one knee, with his foot on the head of Draco, while his head is close to that of Ophiuchus. The constellar tion contains no stars of the iirst or even of the second mag- nitude, but a number of the third. The most characteristic figure is the keystone-shaped quadrilateral formed by the stars ^! t> v> with TT and p together at the northeast corner. It lies about midway on the line from Vega to Corona. The line tte, carried on 11°, brings us to /8, the brightest star of the aster- ism ; and y and k lie a few degrees farther along on the same line continued toward y Serpentis. The angle eySa is a right angle opening towards Lyra, a is irregularly variable, besides being double. 61. Names, a, Ras Algelhi; j3, Korneforos. Double Stars. (1) a, Mags. 3, 6 ; Pos. 119° ; Dist. i".5 ; orange and blue. A very beautiful object for a 4-inch glass (Astr. Fig. 113). (2) f (the S.W. corner of the " Keystone ") , Binary ; period, 34 y. (Astr. Fig. 113); Mags. 3, 6.5; Pos. (1905)190°; Dist. 1".5. Rather difficult for a small instrument. (3) p (2J° east of tt at the N.W. corner of the " Keystone "), Mags. 4, 5 ; Pos. 312° ; Dist. 4" ; white, emerald green. (4) S (on the line from 77 through e produced nearly its own length), Mags. 3, 8 1 Pos. 184° ; Dist. 18" ; white, light blue. Apparently an " optical pair " ; the relative motion being rectilinear. (5) [x (nearly midway between Vega and a Herculis — see map). Triple; Mags. A 4, B 9.5, C 10 ; A, ^ + ^, Pos. 246° ; Dist. 31". B-C, too faint and close for separation by any but large telescopes ; Dist. about 1" ; position angle rapidly changing — about 20° in 1890. (6) 95 Herculis (the N.W. corner of a little quadrilateral [sides 1° to 2°] of fourth and fifth mag. stars, on line from p through ft,, produced two-thirds its length), Mags. 5.5 and 6 ; Pos. 262°; Dist. 6" ; light green, cherry-red. Peculiar in showing contrast of color between nearly equal components. Clusters. (1) M. 13, A.R. 16" 37"' ; Dec. 36° 41'. Exactly on the western boundary of the Keystone, one-third the way from m towards 500 § 51] LYEA. 35 f. On the whole, the finest of all star clusters. (2) M. 92, A.R. 17" 13" ; Dec. 43° 16' (6° north and a little west of p). Fine, but not equal to the other. 52. Lyra (Map IV.). — The great white or blue star Vega sufficiently marks this constellation. It is attended on the east by two fourth-magnitude stars, e and 4 which form with it a little equilateral triangle having sides about 2° long, ji and y of the third magnitude {j3 is variable) lie about 8° southeast from Vega, 2^° apart. Double Stars. (1) Vega itself has a small companion, 11th mag. ; Pos. 160°; Dist. 48". Only optically connected; the small star does not share the proper motion of the larger one, and has been used as a reference point in measuring Vega's parallax. (2) p, multiple; i.e., it has three small stars near it, forming a very pretty object with a low power. (3) Ej and Cj, Quadruple (the northern of the two which form the little triangle with a.) A sharp eye unaided by a telescope splits the star, and a small telescope divides both the components (see Astr. 468, and Fig. 113) : ci (or 4 Lyrse), Mags. 6, 7 ; Pos. 12° ; Dist. 3".2. c-2 (or 5 Lyrse), Mags. 5.5, 6 ; Pos. 132° ; Dist. 2".5. c^ ■:„ Pos. 173° ; Dist. 207". On the whole, the finest object of the kind. (4) f, Mags, 4, 6; Pos. 150°; Dist. 44". (5) r) (10° E. of Vega), Mags. 4.5, 8; Pos. 85°; Dist. 28"; yellow, indigo. (6) 8; fine field for low powers. Nebula. M. 57, the Annular Xebula. A.K. 18" 49-" ; Dec. 32° 53'. Between /? and y, one-third of the way from /3. (Art. 470.) 53. Cygnus (Maps I. and IV.). — This lies due east from Lyra, and is easily recognized by the cross that marks it. The bright star a (1^ magnitude) is at the top, and /3 (third mag- nitude) at the bottom, while y is where the cross-bar from S to £ intersects the main piece, which lies along the Milky Way from the northeast to the southwest. I is (nearly) on the pro- longation of the line from y through c, not quite so far from e as e from y. Names, u., Arided, or Deneb Cygni (there are other Denebs ; e.g., Deneb Kaitos in Cetus) ; fi, Albireo; y, Sadr. 501 36 UEANOGRAPHY. [§ 63 Double Stars. (1) j8, Mags. 3.5, 7; Pos. 56°; Dist. 35"; orange, smalt blue. This is the finest of the colored pairs for a small tele- scope. (2) fx (as far beyond f as ^ is east of e, at the tip of the east- ern wing), Mags. 5 and 6 ; Pos. 118°; Dist. 3".8. (3) x (one-third of the way from /3 towards y), Mags. 5 and 9 ; Pos. 73° ; Dist. 26" ; yel- low and blue. (4) 61 Cygni (easily found by completing the parallel- ogram of which a, y, and e are the other three corners. ; Dec. 47° 54' (about 3° north of p ; p itself (fourth mag.) being found by drawing a line from 8 through a, and carrying it an equal distance beyond. (2) y VIII. 56, A.R. 20'" W" ; Dec. 40° 20'. Beautiful group, J° north and a little east of y. The brigW spots in the Milky Way all through Cygnus afiord beautiful fields for a low power. 54. Vulpecula et Anser (Map IV.). — This little constella- tion is one of those originated by Hevelius, and has obtained more general recognition among astronomers than most of his creations. It lies just south of Cygnus, and is bounded to the south by Delphinus, Sagitta and Aquila. It has no conspicuous stars, but contains one very interesting tele- scopic object, — the " Dumb-Bell Nebula," — M. 27, A.R. W 54" ; Dec. 22° 23'. On a line from y Lyrse through j8 Cygni, produced as far again, where this line intersects another drawn from a Aquite through y Sagittse, 3^° north and half a degree east of the latter star. 55. Sagitta (Map IV.). — This little asterism, though very incon- spicuous, is one of the old 48. It lies south of Vulpecula, and the two stars a and /?, which mark the feather of the arrow, lie nearly midway between j3 Cygni and Altair, while its point is marked by y, 5° farther east and north. Double Stars. (1) f (|° N.W. of 8, the middle star in the shaft of the arrow), Mags. 5.5, 9; Pos. 312°; Dist. 8".6: the larger star is itseK close double, distance about i", making an interesting triple system. 602 § 56] AQUILA. 37 56. Aquila (Map IV.). — This constellation lies on the ce- lestial equator, east of Ophiuchus and north of Sagittarius and Capricornus. It is bounded on the east by Aquarius and Delphinus, and on the north by Sagitta. Its characteristic configuration is that formed by Altaie (the standard first-mag- nitude star), with y to the north and ji to the south. It lies about 20° south of /3 Cygni, and forms a fine triangle with Vega and a Ophiuchi. Double Star. (1) ■n- Aquilae (1J° N.E. of y), Mags. 6 and 7 ; Pos. 120°; Dist. 1".5. Good test for Sfinch glass. Cluster. M. 11, A.R. 18" iS-"; Dec. S. 6° 24'. A fine fan-shaped group of stars in the Milky Way. A line carried from Altair through 8 Aquilse (see map), and prolonged once and a half as far again, will find it about 4° S.W. of A. The southern part of the region allotted to Aquila on our maps has been assigned to Antinoiis. This constellation was recognized by some even in Ptolemy's time ; but he declined to adopt it. Hevelius appro- priated the eastern portion of "Antinoiis" for his constellation of " Scutum Sobieski," and M. 11 falls just within its limits. 57. Sagittarius (Map IV.). — This, the tenth of the zodia- cal constellations, is bounded north by Aquila and Ophiuchus, west by Scorpio and Ophiuchus (though Bode and some other authorities crowd in a piece of " Telescopium " between it and Scorpio), south by Corona Australis, Telescopium, and Indus, and east by Microscopium and Capricornus. It contains no stars of the first magnitude, but a number of the 2^ and third. The most characteristic configuration is the little inverted " milk dipper " formed by the five stars, X, <^, o-, t, and ^, of which the last four form the bowl, while X (in the Milky Way) is the handle. 8, y, and e, which form a triangle right-angled at S, lie south and a little west of X, the whole eight together forming a very striking group. There is a curious disregard of any apparent principle in the lettering of the stars of this constellation; a and ^ are stars not exceeding in brightness 503 38 URANOGRAPHY. [§ 57 the fourth magnitude, about 4° apart on a north and south line and lying some 15° south and 5° east of ^ (see map). The MUky Way in Sagittarius is very bright, and complicated in structure, full of knots and streamers, and dark pockets. Names. A., Kaus Borealis ; S, Kaus Media; e, Kaus Australis ; er, Sddira. This star is strongly suspected of irregular variability. Double Stars. (1) /xi (7° N.W. of A.; on the line from ^ through <^ produced), Triple; Mags. A 3.5, B 9.5, C 10; A-B, Pes. 315°, Dist. 40"; A-C, Pos. 114°, Dist. 45". Clusters and Nebulce. (1) M. 22, A.R. 18" 29°' ; Dee. S. 24° 0' (3° JST.W. of X, and midway between ft, and cr). Capital object for a 4-inch telescope. (2) M. 25, A.R. 18" 25°' ; Dec. S. 19° 10' (7° north and 1° east of X; visible to naked eye). (3) M. 8; A.R. 17" 57'°; Dec. S. 24° 21' (a little south of the line ^X produced, and as far from X as X from <^; also visible to naked eye). (4) ^ IV. 41, The Trifid Nebula, A.R. 17" SS-" ; Dec. S. 23° 2' (lJ-° north of M. 8, and ahnost exactly on the line ijiX produced). A very beautiful and interesting object. 58. Capricornus (Map IV.). — This, the eleventh of the zodiacal constellations, follows Sagittarius on the east. It has Aquarius and Aquila (Antinous) on the north, Microscopium and Piscis Austrinus on the south, and Aquarius on the east. It has no bright stars, but the configuration formed by the two a's (ai and oj) with each other and with p, 3° south, is characteristic and not easily mistaken for anything else. The two a's, a pretty " double " to the naked eye, lie on the line from yS Cygni (at the foot of the cross) through Altair, pro- duced about 25°. On the line a/3, about 3° distant, lies p (of the fourth magnitude), with two other small stars near it. From this a line 20° long, carried due east through $ and t (of the fourth magnitude), brings the eye to y and 8 of the third, the latter marking the constellation's eastern limit. Names, a, Algiedi {piima and secunda) ; 8, Deneb Algiedi. Double Stars. (1) a^ and a, (pretty with a very low power), Mags. 3 and 4 ; Dist. 6' 13". n^ has also a veiy faint companion, invisible 504 § 58] DELPHINUS. 39 with any telescope of less than 6-inch aperture ; Pos. 150°; Dist. 7".5. The companion is itself double; Dist. about 1"; Pos. 240°. (2) p, Mags. 3.5, 7 ; Pos. 267° ; Dist. 3' 25". The companion is also a close and difficult double. (3) p (the northern star in the little triangle it forms with t and o), Mags. 5, 9; Pos. 177°; Dist. 8".8. (4) tt (the S.W. one in the same triangle), Mags. 5, 9 ; Pos. 146°; Dist. 3".5. Nebula. M. 30, A.R. 21" 34°' ; Dec. S. 23° 42' (about 1° west and a little north of 41 Capricorni, a fifth-magnitude star, 7° south of y Capricorni). 59. DelpMnus (Map IV.). — This little asterism is ancient, and unmistakably characterized by the rhombus of third-mag- nitude stars known as " Job's Coffin." It lies about 15° north- east of Altair, bounded north by Vulpecula and west by Aquila. There are a few stars visible to the naked eye in addition to the four that form the rhombus. Epsilon, about 3° southwest^ is the only conspicuous one. Names, a, Svalocin; /3, Rotanev. These were given in joke by Nicolaus Caociatore, a Sicilian astronomer, about 1800. The letters of the two names reversed make Mcolavs Venator; Venator being the translation of the Italian " Cacciatore," which means "Hunter." The joke is good enough to keep. X Double Stars. (1) y (at the N.E. angle of the rhombus), Mags. 4, 7; Pos. 271°; Dist. 11".3. (2) j3, a very close and rapid binary, beyond the reach of all but large telescopes. It has, however, two little companions, distant about 30". 60. Equuleus (Map IV.). — This little constellation is still smaller than the Dolphin, and contains no such characteristic star group. It lies about 20° due east of Altair, and 10° S.E. of Delphinus (see map). Double Stars. (1) £, Mags. 5, 7.5; Pos. 73°; Dist. 11". The larger star is also close double ; Mags. 5.5. and 7 ; Pos. 290° ; Dist. 0".9. Per- haps resolvable with a 4-inch telescope. 61. Lacerta (Maps I. and IV.). — This is one of Hevelius's mod- ern constellations, lying between Cygnus and Andromeda, with no stars above the 4J magnitude. It contains a few telescopic objects, but nothing suited to our purpose. 506 40 T7EAN0GRAPHT. [§ ^^ 62. P6g«su8 (not Pegas'us) (Map IV.). — This covers an immense space which is bounded on the north by Andromeda and Lacerta, on the west by Cygnus, Vulpecula, Delphinus, and Equuleus, on the south by Aquarius and Pisces, and on the east by Pisces and Andromeda. Its most notable config- uration is " the great square," formed by the second-magnitude stars a, p, and y Pegasi, in connection with u, Andromedae (sometimes lettered 8 Pegasi) at its northeast corner. The stars of the square lie in the body of the horse, which has no hindquarters. The line drawn from u, Andromedse through a Pegasi, and produced about an equal distance, passes through ^ and ^ in the animal's neck, and reaches 6 (third magnitude) in his ear. Epsilon, 8° northwest of 6, marks his nose. The forelegs are in the northwestern part of the constellation just east of Cygnus, and are marked, one of them by the stars -q and IT, the other by i and k. Names, a, Markah ; /8, Scheat; y, Algenib ; e, Enif. Double Star, k, Mags. 4, 11 ; Pos. 302° ; Dist. 12". The large star is also itself an extremely close double; Dist. 0".3; (pointed at by the northern edge of the " square," at a distance one and a quarter times its length.) Cluster. M. 15, A.R. 21" 24°' ; Dec. 11° 38' (on the fine from $ through £, produced half its length, and just west of a sixth-magni- tude star). j^ 63. Aquarius (Map IV.). — This, the twelfth and last of the zodiacal constellations, extends more than 3^ hours in right ascension, covering a considerable region which by rights ought to belong to Capricornus. It is bounded north by Delphinus, Equuleus, Pegasus, and Pisces ; west by Aquila and Capricornus ; south by Capricornus and Piscis Austrinus, and east by Cetus. The most notable configuration is the little Y of third and fourth magnitude stars which marks the "water jar" from which Aquarius pours the stream that meanders down to the southeast and south for 30°, till it 506 § 63] PISCIS AUSTEINUS. 41 reaches the Southern Fish. The middle of the Y is about 18° south and west of u, Pegasi, and lies almost exactly on the celestial equator. A line drawn west and a little south from y (the westernmost star of the Y) to a Capricorni, passes through fi (third magnitude) at one-third of the way, and through /x and e (fourth and 3\) two-thirds of the way. a (third magnitude) lies 4° west and a little north of y. 8 (third magnitude) lies aboat half-way between the Y and Fomalhaut in the Southern Fish, 3° or 4° east of the line that joins them. Names, a, Saad el Melik ; y3, Saad el Sund ; 8, Skat. Double Stars. (1) f (the central star of the Y), Mags. 4, 4.5; Pos. 332° ; Dist. 3".6 ; pretty and easy. (2) 12 Aquarii (7° due west of /3, and the brightest star in the vicinity), Mags. 5.5, 8.5 ; Pos. 190° ; Dist. 2". 8 ; yellowish white and light blue. Clusters and Nebula;. (1) M. 2 ; A.R. 21i> 17-° ; Dec. S. 1° 22' (on the line drawn from t, through u, produced one and a quarter times its own length). (2) H IV. 1, A.R. 20" SS"; Dec. S. 11° 50' (nearly on the line from a through p, produced its own length, and 1J° west of V ; fifth magnitude) ; planetary nebula, bright and vividly green. 64. Piscis Austrinus {or Australis) (Map IV.). — This small constellation, lying south of Aquarius and Capricornus, pre- sents little of interest. It has one bright star, Fomalhaut (pronounced FomaUiawt), of the 1^ magnitude, which is easily recognized from its being nearly on the same hour-circle with the western edge of the great square of Pegasus, 46° to the south of ix, and solitary, having no star exceeding the fourth magnitude within 16° or 20°. It contains no telescopic objects available for our purpose. South of it, barely rising above the southern horizon, lie the con- stellatious of Microscopium and Grus. The former is of no account. The latter is a conspicuous constellation in the southern hemisphere, and its two brightest stars, u and j8, of the second magnitude, rise high enough to be seen in latitudes south of Washington. They lie about 20° south and west of Fomalhaut. 607 Magnitudes 1 S S ^ 6 Netula GUtiter Symbols m * * * + • ° ® 9 P.M. MAPI. Magnitudes 1 2 S 4 5 Neiula Cluty^r Symbol s ^ jfe :>: ^ -t- . O ® w. MAP II. DECEMBER li5 I I • NOVEMBER 1.5 \ CASSIOP. +H + < PERSEUS *. / m° \- \ ^. E '^ar. PVi TV ,j ^-- ANDROW'EipA . / TRIANipLUM .-'"^ Tt + I T. A^ + « T*- ■k • a* ^ J M ^^J ANTLIA j ARPO NAVIS + +• \ r* irAURUS r*^ • + (VELA) Magnitudes 1 8 S 4' 5 Nebula Clutter " " ' ^ » * • -^ ' o ®_ M. SEPTEMBER 1,5 AUGUST 1,5 MAPW . JULY @MS9 . • I Deneb *oc +'' «* /' 1" +< af9«® CYGNUS^ + 4. \. 1— ^^1 Ring Nep1.ila • f^'i- HERCULES 30 •"^-^'A +1 VULPECnLA. Mi 9 Dumb' bell ^^^ . > -r- •I 1 + 1+ I ELPHINUSI Ttta tM®,— 1^ T h -5- I \Fo»T 10 '■4 lAl ait' r/r pa • St- AQUItAjf ' .rc ^ * OPHIUCHHS 10 ■t-+l --k? ■^<' ^«¥HI- ^SEHPENir I + ^ II ctr. -;, ^^< • \A .?) +;« TEXTBOOKS ON ASTRONOMY By Charles A. Young Late Professor of Astronomy in Princeton University LESSONS IN ASTRONOMY (Revised Edition). Including Star Maps. ix + 420 pages, illustrated, ^1.25. ELEMENTS OF ASTRONOMY. With a Uranography. 464 + 42 pages and four double-page star maps, ^1.60. Uranography. From the " Elements of Astronomy." Flexible covers, 42 pages and four double-page star maps, 30 cents. MANUAL OF ASTRONOMY. 611 pages, illustrated, S2.25. GENERAL ASTRONOMY. A textbook for colleges and scientific schools. 630 pages, illustrated with 250 cuts and diagrams and supplemented with the necessary tables, $2.7^. A SERIES of textbooks on astronomy for higher schools, acad- ■^^ emies, and colleges, prepared by one of the most distinguished astronomers of the world, a popular lecturer and a successful teacher. The " Lessons in Astronomy " was prepared for schools that desire a brief course free from mathefnatics. The book is fully down to date, and several beautiful plates of astronomical objects and instruments have been inserted in the revised edition. The " Elements of Astronomy " is a textbook for advanced high schools, seminaries, and brief courses in colleges generally. Special attention has been paid to making all statements accurate. The " Manual of Astronomy " is a new work prepared in response to a pressing demand for a classroom textbook intermediate between the author's " General Astronomy" and his " Elements of Astronomy." It is largely made up of material drawn from the earlier books, but re- arranged, rewritten when necessary, and added to in order to suit it to its purpose and to bring it thoroughly down to date. The eminence of Professor Young as an original investigator in astronomy, a lecturer and writer on the subject, and an instructor in college classes, led the publishers to present the " General Astronomy" with the highest confidence; and this confidence has been fully justified by the event. It is conceded to be the best astronomical textbook of its grade. , GINN AND COMPANY Publishers LABORATORY AND EXERCISE MAN- UALS IN ASTRONOMY WILLSON'S LABORATORY ASTRONOMY By Robert W. Willson, Professor of Astronomy, Harvard University Svo, cloth, 189 pages, illustrated, §1.25 This book outlines a course in astronomy in which the fundamental principles are developed by laboratory and home observations of celes- tial phenomena. All the more important celestial motions are studied. The arrangement is logical and interesting. The book can be used in connection with any good textbook in elementary astronomy and is suitable for college students or pupils in the last years of high school. WHITING'S DAYTIME AND EVENING EXERCISES IN ASTRONOMY By Sarah Frances Whiting, Whitin Observatory, Wellesley College i2mo, cloth, XV 4- 104 pages, illustrated, 75 cents In this laboratory course in astronomy the study of illustrative appa- ratus and of photographs of celestial bodies largely, though not wholly, replaces telescopic observation, making the class independent of atmos- pheric conditions and relieving it of much of the burden of evening work. The method of presentation leaves the student, wherever possi- ble, to draw his own conclusions from the data discussed. The course has been used successfully with college classes. BYRD'S LABORATORY MANUAL IN ASTRONOMY By Mary E. Byrd, recently Director of the Observatory, Smith College Svo, cloth, 273 pages, illustrated, Si. 25 This manual offers elementary laboratory work and is especially suit- able for secondary schools or beginning astronomy classes in college. One third of the book is devoted to practical exercises on almanacs, globes, and time. The remainder is largely made up of observations with the unaided eye and with homemade instruments. 164 GINN AND COMPANY Publishers THE ELEMENTS OF GEOLOGY By WILLIAM HARMON NORTON Professor of Geology in Cornell College, Mt. VernoHj Iowa 8vo, cloth, 461 pages, illustrated, S1.40 THE essentials of the science of geology are treated with fullness and ample illustration in this text-book for beginners. By limiting his discussion chiefly to this continent the author has been able to devote a large amount of space to the principles which he describes. The following characteristics are important. 1. The outline is exceptionally simple. Under the leading geological processes are grouped the rock structures and land forms of which they are the cause. 2. The inductive method is emphasized throughout. Concrete examples are given large space as the basis of generalizations of the science. Numerous exercises and problems, many of vfhich are in the form of diagrams, are designed to train the pupil and to test his knowledge. 3. The cycle idea is made prominent, and both the records of erosion and those of sedimentation are given special attention. 4. In historical geology a broad view is afforded of the development of the North American continent and of the evolution of life upon the earth. Only the leading types of plants and animals are mentioned, and special attention is given to those which mark the lines of descent of forms now living. The book is designea for use in high schools and acad- emies, and may also be found useful in short elementary college courses. GINN & COMPANY Publishers TEXTBOOKS IN ASTRONOMY, GEOLOGY, AND PHYSICAL GEOGRAPHY FOR HIGHER SCHOOLS AND COLLEGES ASTRONOMY Byrd : Laboratory Manual in Astronomy $1.25 Greene: Introduction to Spherical and Practical Astronomy . 1.50 Upton : Star Atlas 2.00 Whiting: Exercises in Astronomy .75 Willson : Laboratory Astronomy 1.25 Young : Elements of Astronomy. With Uranography . . . i .60 Young: General Astronomy 2.75 Young : Lessons in Astronomy (Revised Edition). With Uranography . . 1.25 Young : Manual of Astronomy . . . . 2.25 GEOLOGY AND PHYSICAL GEOGRAPHY Davis : Elementary Meteorology .... . . 2.50 Davis: Elementary Physical Geography . . .... 1.25 Davis: Physical Geography .... 1.25 Davis: Exercises in Physical Geography. With Atlas . . . .75 Davis : Harvard Geographical Models. Per set of three . . 20.00 Gregory, Keller, and Bishop : Physical and Commercial Geography . ... 3.00 Norton : Elements of Geology ... . ... 1 .40 Russell: Glaciers of North America . . .... 1.75 Russell: Lakes of North America ... 1.50 Trafton : Laboratory and Field Exercises in Physical Geog- raphy . . . . ... .40 Ward: Practical Exercises in Elementary Meteorology . . 1.12 Wright : Field, Laboratory, and Library Manual of Physical Geography 1. 00 146 b GINN AND COMPANY Publishers