Half-hours with the Telescope eBook

Richard Anthony Proctor
This eBook from the Gutenberg Project consists of approximately 98 pages of information about Half-hours with the Telescope.

There are two other objects conveniently situated for observation, which the observer may now turn to.  The first is the great cluster in the sword-hand of Perseus (see Plate 4), now lying about 28 deg. above the horizon between N.E. and N.N.E.  The stars [gamma] and [delta] Cassiopeiae (see Map 3 of Frontispiece) point towards this cluster, which is rather farther from [delta] than [delta] from [gamma], and a little south of the produced line from these stars.  The cluster is well seen with the naked eye, even in nearly full moonlight.  In a telescope of moderate power this cluster is a magnificent object, and no telescope has yet revealed its full glory.  The view in Plate 5 gives but the faintest conception of the glories of [chi] Persei.  Sir W. Herschel tried in vain to gauge the depths of this cluster with his most powerful telescope.  He spoke of the most distant parts as sending light to us which must have started 4000 or 5000 years ago.  But it appears improbable that the cluster has in reality so enormous a longitudinal extension compared with its transverse section as this view would imply.  On the contrary, I think we may gather from the appearance of this cluster, that stars are far less uniform in size than has been commonly supposed, and that the mere irresolvability of a cluster is no proof of excessive distance.  It is unlikely that the faintest component of the cluster is farther off than the brightest (a seventh-magnitude star) in the proportion of more than about 20 to 19, while the ordinary estimate of star magnitudes, applied by Herschel, gave a proportion of 20 or 30 to 1 at least.  I can no more believe that the components of this cluster are stars greatly varying in distance, but accidentally seen in nearly the same direction, (or that they form an enormously long system turned by accident directly towards the earth), than I could look on the association of several thousand persons in the form of a procession as a fortuitous arrangement.

Next there is the great nebula in Andromeda—­known as “the transcendantly beautiful queen of the nebulae.”  It will not be difficult to find this object.  The stars [epsilon] and [delta] Cassiopeiae (Map 3, Frontispiece) point to the star [beta] Andromedae.  Almost in a vertical line above this star are two fourth-magnitude stars [mu] and [gamma], and close above [nu], 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 transcendantly beautiful queen of the nebulae is rather a disappointing object in an ordinary telescope.  There is seen a long oval or lenticular spot of light, very bright near the centre, 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.

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Half-hours with the Telescope from Project Gutenberg. Public domain.
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