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Fig. 7c. Planetary Nebula, N. G. C. 7.009. Photographed at the Lick Observatory. Two exposures, one short and one long.
Page:Popular Science Monthly Volume 87.djvu/232
Fig. 7c. Planetary Nebula, N. G. C. 7.009. Photographed at the Lick Observatory. Two exposures, one short and one long.