OCR Text |
Show Have Catalogue of Stars, At Cambridge, Mass., there now exists ex-ists tbe most extensive and valuable collection of stellar photographs In the world, numbering over 240,000; and 100,000 or more of them have been secured at Harvard University Observatory at Arequlpa, Peru, at an elevation of 8.000 feet. The number of stars revealed on tfce different pla'ts depends, of course, on the den-sltj den-sltj of the part of the sky being photographed, pho-tographed, and on the length of the exposure, tbe longer the exposure the more stars, provided tbe light of tbe sky does not fog the plate. On one plate alone, namely the region about Eta Carlnae, 240,000 stars have been actually counted. |