Pleasures of the telescope: An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General ReadersServiss, Garrett Putman
Science
Pleasures of the telescope: An Illustrated Guide for Amateur Astronomers and a Popular Description of the Chief Wonders of the Heavens for General Readers
With either of our telescopes we shall have a feast for the eye when we
turn the glass upon the star cluster No. 1454, some four degrees south
of Sirius. Look for a red star near the center. Observe the curving rows
so suggestive of design, or rather of the process by which this cluster
was evolved out of a pre-existing nebula. You will recall the winding
streams in the Great Nebula of Orion. Another star cluster worth a
moment's attention is No. 1479, above and to the left of Sirius. We had
better use the five-inch for this, as many of the stars are very faint.
Not far away we find the double star , whose components are of the fifth
and eighth magnitudes, distance 2.8", p. 343 deg.. The small star is pale
blue. Cluster No. 1512 is a pleasing object with our largest aperture.
In No. 1511 we have a faint nebula remarkable for the rows of minute
stars in and near it. The star gamma is an irregular variable. In 1670
it is said to have almost disappeared, while at the beginning of the
eighteenth century it was more than twice as bright as it is to-day. The
reddish star delta is also probably variable. In my "Astronomy with an
Opera Glass" will be found a cut showing a singular array of small stars
partly encircling delta. These are widely scattered by a telescope, even
with the lowest power.
Eastward from Canis Major we find some of the stars of Argo Navis. Sigma
1097, of the sixth magnitude, has two minute companions at 20" distance,
p. 311 deg. and 312 deg.. The large star is itself double, but the distance,
0.8", p. 166 deg., places it beyond our reach. According to Burnham, there
is yet a fourth faint star at 31", p. 40 deg.. Some three degrees and a half
below and to the left of the star just examined is a beautiful star
cluster, No. 1551. Nos. 1564, 1571, and 1630 are other star clusters
well worth examination. A planetary nebula is included in 1564. With
very powerful telescopes this nebula has been seen ring-shaped. Sigma
1146, otherwise known as 5 Navis, is a pretty double, colors pale yellow
and blue, magnitudes five and seven, distance 3.25", p. 19 deg.. Our
three-inch will suffice for this.
[Illustration: MAP NO. 3.]
Public-domain text, read in full here on John Shaqi.
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