Democratic Sentinel, Volume 17, Number 3, Rensselaer, Jasper County, 3 February 1893 — POPULAR SCIENCE NOTES. [ARTICLE]

POPULAR SCIENCE NOTES.

It is a popular test of the power of an opera or a Held glass to try to sight four of Jupiter's moons. To ascertain the limit of a small telescope, having object glasses of 2 1-4 to 2 3-4 inches in diameter, try to sight the rings of Suturn. Bio and Litti.e Telescopes. —“ Great Telescopes” was the subject of an address delivered recently before the Chicago Academy of Sciences in the Athieneum building by Professor J. E. Keeler, formerly astronomer at the Lick Observatory, now director of the Allegheny Observatory, Allegheny, Pa. A lirgc and attentive audience, composed chiefly of professors and scientists, listened to the lecture, which lasted more than two hours. “The popular idea of telescopes,” said the professor, “is wholly erroneous. There is no use of increasing the magnitude of the lenses beyond a certain size. Nothing is gained. I have frequently been able to do more and better work on a clear night with a little two-inch lens of my own manufacture than was possible on a. ‘twinkling’ night with the great Lick telescope. The only real advantage possessed by the great telescopes is a much higher resolving power—that is, through the great lenses astronomers are able to distinguish an appreciable distance between two stars so close together that they have always been regarded as one. “The Lick telescope was an experiment, and the Chicago telescope will lie a further experiment in the same line, lu atmospheric conditions Chicago will have to yield the palm to Ciliforuia, although I do not doubt that the new observatory, taking advantage of past experiments, will be the most complete and perfect in existence."