What is the origin of the letters used in star classification? Why didn't astronomers use ABCD? J. HaldimanChicago, Illinois ...

THE author has brought together in a small compass a list of the more prominent objects in the heavens for the use of possessors of small telescopes. The list is accompanied also by brief historical ...

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Stellar spectral types were initially arranged alphabetically; however, subsequent detailed observations led to the consolidation and reordering of categories, establishing the current OBAFGKM ...