Half-hours with the TelescopeNext there is the great nebula in Andromeda -- known as "the transcendently beautiful queen of the nebulæ." It will not be difficult to find this object. The stars ε and δ Cassiopeiæ (Map 3, Frontispiece) point to the star β Andromedæ. Almost in a vertical line above this star are two fourth-magnitude stars μ and γ, and close above ν, a little to the right, is the object we seek -- visible to the naked eye as a faint misty spot. To tell the truth, the transcendently beautiful queen of the nebulæ is rather a disappointing object in an ordinary telescope. There is seen a long oval or lenticular spot of light, very bright near the center, especially with low powers. But there is a want of the interest attaching to the strange figure of the Great Orion nebula. The Andromeda nebula has been partially resolved by Lord Rosse's great reflector, and (it is said) more satisfactorily by the great refractor of Harvard College. In the spectroscope, Mr. Huggins informs us, the spectrum is peculiar. Continuous from the blue to the orange, the light there "appears to cease very abruptly;" there is no indication of gaseity. Lastly, the observer may turn to the pair Mizar and Alcor, the former the middle star in the Great Bear's tail, the latter 15' off. It seems quite clear, by the way, that Alcor has increased in brilliancy of late, since among the Arabians it was considered an evidence of very good eyesight to detect Alcor, whereas this star may now be easily seen even in nearly full moonlight. Mizar is a double star, and a fourth star is seen in the same field of view with the others (see Plate 5). The distance between Mizar and its companion is 14"·4; the magnitude of Mizar 3, of the companion 5; their colors white and pale green, respectively. |