Dr. Helena (or Heleen as she was called by family and friends) Kluyver was born in Leiden on 26 January 1909. She studied astronomy at Groningen (1928 - 1930), was appointed Secretary of Leiden Observatory, and continued her studies at Leiden (1931 - 1934). Her master's degree had theoretical astronomy as major; physics and mathematics as minors. She obtained her doctorate at Leiden on 22 June 1954, on a thesis "Line Intensities in the Spectrum of RR Lyrae", with Prof. Henk C. van de Hulst as promotor (thesis advisor).
Heleen Kluyver worked at Leiden Observatory from January 1931 till about 1980. For a number of years she worked with Dr. J. Woltjer in theoretical astrophysics, concentrating on the pulsation theory of Cepheids. This work led to several publications in the Bulletin of the Astronomical Institutes of the Netherlands (BAN). In 1932 she worked a few months at Harvard, with Dr. Cecilia H. Payne (later: Payne Gaposchkin), on spectra of novae and Wolf-Rayet stars.
From 1935 to 1948 Heleen Kluyver assisted Prof. J.H. Oort in his duties as General Secretary of the International Astronomical Union. And for many years, until 1964, she handled the editorial affairs of the Bulletin of the Astronomical Institutes of the Netherlands (now part of the Astronomy & Astrophysics journal) and of other Leiden Observatory publications.
Heleen Kluyver married Gerrit Pels, an astronomer at the Leiden Observatory. With him, she worked on the orbits of comets (Pels-Kluyver 1960, BAN 15, 163, 1960); and on stellar motions in the Hyades cluster, with a discussion of membership and structure of the cluster (Pels, Oort and Pels-Kluyver 1975, A&A 43, 423). Gerrit Pels died in 1966, and Heleen Kluyver later remarried with an other astronomer, Bert van Herk.
Heleen Kluyver died on 15 November 2001, at the age of 92.