The Adolfo Stahl lectures in astronomy, delivered in San Francisco, California, in 1916-17 and 1917-18, under the auspices of the Astronomical Society of the Pacific (1919)
Astronomical Society of the Pacific, Aitken, Robert Grant, 1864-1951 · San Francisco Stanford University Press · leaf 167
Fig. 1—.-^t left, region in the Milky Way showing ten to twenty thousand stars,one planetary (N. G. C. 6563), and no spirals. Fig. 2—At right, region near N. G. C. 2507, some distance from the Milky Way,showing few stars and tifty-thrce small nebulae, indicated by rings. Thearea of eacli lialf is… … Fig. 3—At left, is a drawing of the Spiral Nelnda, Messier 11)1, made by Hunterin 1851 with the 6-foot reflector of Lord Rosse. Fig. 4—At right, a photograph of the same nebula. PLATE XXII. Photographs of Spiral Xehulae bv H. D. Curtis; DrawingOF Messier 101 bv S. Hunter. The Nebulae 101 of spiral…
Astronomy
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