51 Zubenisch Mali 2 1 The Scorpion ..... 44 Antares The Archer 69 ....... The Goat.............. 51 The Water-carrier 108 Scheat ............................................ Constellations on the North Side of the Zodiac. Constellations. No. Principal Stars and .... The Little Bear Cepheus........ terian and Chara Cor. Caroli .......... Perseus ................ 59 Algenib 60 Rastaber The Greyhounds.. 25 Charles' Crown.... 3 Triangulum ................ The Triangle........ 16 Triangulum Minus...... The Lesser Triangle 5 Musca Lynx..... 1 21135 35 The Bee .............. 6 Leo Minor ..... The Little Lion .... 24 Changes among the fixed stars. as far distant from each other as from the centre, and supposing the nearest fixed stars to be as far distant from each other as from the sun, he concludes that there can strictly speaking be only 13 stars of the first magnitude. Hence at twice that distance from the sun there may be placed four times as many, and so on; and this mode of calculation gives us pretty nearly the number of stars of the first, second, third, &c. magnitudes. It is a fact no less singular than well ascertained, that stars which were observed by the ancients are now no longer to be seen, and new ones have appeared in different places, which were unknown to the ancients, and some of these have also disappeared and again become visible. Hipparchus, the ancient astronomer, having observed the disappearance of a star, was induced to make a catalogue of the fixed stars, that posterity might judge whether any other change took place among them. Many ages afterwards, a new star having been observed by Tycho Brahe and his contemporaries, this astronomer also determined to make a catalogue with the same view as Hipparchus. Of the new star seen by Brahe, and on the subject of changes among the stars in general, we have the following interesting account by Dr. Halley: "The first new star in the Chair of Cassiopeia was not seen by Cornelius Gemma on the 8th of November, 1572, who says, he, that night, considered that part of the heaven in a very serene sky, and saw it not; but that the next night, November 9, it appeared, with a splendour surpassing all the fixed stars, and scarcely less bright than Venus. This was not seen by Tycho Brahe before the 11th of the same month; but from thence he assures us that it gradually decreased and died away; so as in March, 1574, after 16 months, to be no longer visible; and at this day no signs of it remain. Its place in the sphere of fixed stars, by the accurate observations of the same Tycho, was 0' 9° 17′ a 1ma, with 53° 45′ north latitude. Such another star was seen and observed by the scholars of Kepler, to begin to appear on September 30, St. Vet. anno 1604, which was not to be seen the day before; but it broke out at once with a lustre surpassing that of Jupiter; and like the former, it died away gra dually, and in much about the same time disappeared totally, there remaining no footsteps thereof in January, 1605-6. This was near the ecliptic, following the right leg of Serpentarius; and by the observations of Kepler and others, was in 7' 28° 0′ a Ima Y, with north latitude 1° 56'. These two seem to be of a distinct species from the rest, and nothing like them has appeared since. But between them, viz. in the year 1596, we have the first account of the wonderful star in Collo Ceti, seen Changes among the fixed stars. by David Fabricius on the 14th of August, as bright as a star of the third magnitude, which has been since found to appear and disappear periodically; its period being precisely enough seven revolutions in six years, though it returns not always with the same lustre. Nor is it ever totally extinguished, but may at all times be seen with a six feet tube, [telescope.] This was singular in its kind, till that in Collo Cygni was discovered. It precedes the first star of Aries 1° 40', with 15° 57' south latitude. Another new star was first discovered by William Jansonius, in the year 1600, in Pectore, or rather in Eductione Colli Cygni, which exceeded not the third magnitude. This having continued some years, became at length so small, as to be thought by some to have disappeared entirely; but in the years 1657, 1658, and 1659, it again arose to the third magnitude; though soon after it decayed by degrees to the fifth or sixth magnitude, and at this day is to be seen as such in 9 18° 38' a 1ma Y, with 55° 29′ north latitude. A fifth new star was first seen by Hevelius in the year 1670, on July 15, St. Vet. as a star of the third magnitude; but by the beginning of October, was scarcely to be perceived by the naked eye. In April following, it was again as bright as before, or rather greater than of the third magnitude, yet wholly disappeared about the middle of August. The next year, in March, 1672, it was seen again, but not exceeding the sixth magnitude: since when, it has been no further visible, though we have frequently sought for its return; its place is 9 3° 17′ a 1, and has lat. north 47° 28'. The sixth and last is that discovered by G. Kirch in the year 1686, and its period determined to be of 4044 days, and though it rarely exceeds the fifth magnitude, yet it is very regular in its returns, as we found in the year 1714. Since then we have watched, as the absence of the moon and the clearness of the weather would permit, the first beginning of its appearance in a six feet tube, that, bearing a very great aperture, discovers most minute stars. And on June 15th last, it was first perceived like one of the first telescopical stars; but in the rest of that month and July, it gradually increased, so as to become in August visible to the naked eye, and so continued till the month of September. After that it again died away by degrees: and on the 8th of December, at night, was scarcely discernable by the tube; and as near as could be guessed, equal to what it was at its first appearance on June 15, so that this year it has been seen in all nearly six months, which is but little less than half its period; and the middle, and consequently the greatest brightness, falls about the 10th of September." List of the constellations. Constellations on the North Side of the Zodiac (continued.) Constellations. No. Principal Stars and of Stars. their Magnitudes. Herculus, cum Ramo Hercules kneeling 113 Ras Algiatha .... 3 et Cerbero Serpentarius sive Ophiuchus ...... Taurus Poniatowski .. Lyra 7 1 The Harp...... 22 Vega.. Vulpecula et Anser.... The Fox & Goose 37 Sagitta.... Aquila....... Delphinus Cygnus Equaleus Lacerta Pegasus. Andromeda 18 40 Altair The Arrow The Eagle The Dolphin 18 The Swan.............. 73 Deneb Adige The Horse's Head 10 The Lizard ........ 16 The Flying Horse 85 Markab 66 Almaac 22 List of the constellations. Constellations on the South Side of the Zodiac (continued.) Touean.... The Altar .... 9 The Telescope 9 Southern Crown .. 12 14 The Indian .......... 12 .......... 14 American Goose.. 9 Piscis Australis ....... The Southern Fish 20 Tomalhaut........ 1 The whole number of stars reckoned in the preceding lists, amounts to 3192, but the number which may be discerned with the assistance of telescopes is incalculable. Dr. Hook, with a telescope of twelve feet, saw 78 stars among the Pleiades; and with a longer telescope still more; and in the constellation Orion, which is usually reckoned to contain 78 stars, there have been seen 2000. Dr. Herschel, with a telescope that magnifies from five to six thousand times, has counted fortyfour thousand in a space of sky, eight degrees in length, and three in width; and supposing this quantity to be the same in all portions of the sky, of equal dimensions, the whole number of stars, that may be rendered visible by such a telescope, cannot be fewer than seventy-four millions. Kepler has made a very ingenious observation upon the magnitudes and distances of the fixed stars. He observes, that there can be only thirteen points upon the surface of a sphere, 25. VOL. I. 4 E |
