Adriaan Van Maanen on the Significance of Internal Motions in Spiral Nebulae

Fernie J. D. , “The Historical Quest for the Nature of the Spiral Nebulae”, Publications of the Astronomical Society of the Pacific, lxxxii (1970), 1189–1230; Hetherington Norriss S. , “Adriaan van Maanen and Internal Motions in Spiral Nebulae: A Historical Review”, Quarterly journal of the Royal Astronomical Society, xiii (1972), 25–39; Berendzen R. and Hart R. , “Adriaan van Maanen's Influence on the Island Universe Theory”, Journal for the history of astronomy, iv (1973), 46–56 and 73–98.

van Maanen A. , “Preliminary Evidence of Internal Motion in the Spiral Nebula Messier 101”, The astrophysical journal, xliv (1916), 210–28.

van Maanen Adriaan , “Internal Motion in the Spiral Nebula Messier 33”, Proceedings of the National Academy of Sciences, vii (1921), 1–5.

See op. cit. (ref. 1).

van Maanen A. , “Preliminary Evidence of Internal Motion in the Spiral Nebula Messier 101 from plates taken by G. W. Ritchey, J. E. Keeler, C. D. Perrine and H. D. Curtis, measured and discussed by A. van Maanen”, 13-page handwritten draft of van Maanen's 1916 paper (ref. 2), at the Hale Observatories.