Note 7 — PART I. CLASSIFICATION OF NEBULAE
Reading edition
The classification was presented in the form of a memorandum to the Commission on Nebulae of the International Astronomical Union in 1923. Copies of the memorandum were distributed by the chairman to all members of the Commission. The classification was discussed at the Cambridge meeting in 1925, and has been published in an account of the meeting by Mrs. Roberts in
L’Astronomie
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40
, 169, 1926. Further consideration of the matter was left to a subcommittee, with a resolution that the adopted system should be as purely descriptive as possible, and free from any terms suggesting order of physical development (
Transactions of the I.A.U.
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2
, 1925). Mrs. Roberts’ report also indicates the preference of the Commission for the term “extra-galactic” in place of the original, and then necessarily non-committal, “non-galactic.”
Meanwhile K. Lundmark, who was present at the Cambridge meeting and has since been appointed a member of the Commission, has recently published (Arkiv für Matematik, Astronomi och Fysik, Band 19B, No. 8, 1926) a classification, which, except for nomenclature, is practically identical with that submitted by me. Dr. Lundmark makes no acknowledgments or references to the discussions of the Commission other than those for the use of the term “galactic.”