Page:Popular Science Monthly Volume 31.djvu/203

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ASTRONOMY WITH AN OPERA-GLASS.
191

powerful absorptive atmosphere, and which are believed on various grounds to be, as Lockyer has said, "in the last visible stage of cooling"; in other words, almost extinct. This great, red star probably in actual size exceeds our sun, and no one can help feeling the sublime nature of those studies which give us reason to think that here we can

Scorpio and Sagittarius.

actually behold almost the expiring throes of a giant brother of our giant Sun. Only, the lifetime of a sun is many millions of years, and its gradual extinction, even after it has reached a stage as advanced as that of Antares is supposed to be, may occupy a longer time than the whole duration of the human race.

The opera-glass will show a number of faint stars scattered around Antares. Turn now to Beta (ß) in Scorpio, with the glass. A very pretty pair of stars will be seen hanging below ß. Sweeping down, ward from this point to the horizon you will find many beautiful star-fields. The star marked Nu (ν) is a double which you will be able to separate with a powerful field-glass, the distance between its components being 40".

And next let us look at a star-cluster. You will see on the map an object marked 4 M., near Antares. Its designation means that it is No. 4 in Messier's catalogue of nebulæ. It is not a true nebula, but a closely compacted cluster of stars. With the opera-glass, if you are looking in a clear and moonless night, you will see it as a curious nebulous speck. With a field-glass its real nature is more apparent, and it is seen to blaze brighter toward the center. It is, in fact, one of those universes within the universe where thousands of suns are associated together by some unknown law of aggregation into assemblages of whose splendor the slight view that we can get gives us but the faintest conception.