Julie Marie Vinter Hansen was born on 20 July 1890 in Copenhagen, Denmark, the daughter of Jørgen Hansen (1837–1911), a teacher, politician and pioneer of the cooperative movement on Zealand, and Rasmine Sophie Vinter (1848–1929), who came from a seafaring family and was herself connected to the women’s movement. After her father’s parliamentary career ended, the family settled in Copenhagen. Julie attended N. Zahles Skole, a prominent girls’ school, and passed her studentereksamen in 1910. The following year she entered the University of Copenhagen to study physics with a concentration in astronomy.
While still a student she was appointed in 1915 as a computer at the university’s astronomical observatory on Østervold. The work consisted of laborious hand calculations of planetary perturbations, asteroid and comet orbits, and ephemerides, using logarithmic tables and mechanical calculators such as the Odhner machine. She was the first woman to hold any appointment at the university. In 1917 she became the first woman in Denmark to earn the degree of mag.scient. in astronomy. At first she considered a career in insurance mathematics, but Professor Elis Strömgren recognised her talent and arranged a newly created assistant post at the observatory in 1919.
A 1921 law opened public civil-service positions to women (with the exceptions of the church and the military). In 1922 Vinter Hansen was appointed observator, becoming both the first woman to hold a regular civil-service post at the University of Copenhagen and the first female observer at a European observatory. She lived in the observatory residence on Østervold for the rest of her life; her mother shared the house until 1929. By 1939 she was First Astronomer at the observatory and was widely known for the precision of her orbital computations of minor planets and comets. Her long series of calculations for Comet Comas Solá, discovered in 1926, was especially praised for its accuracy; she successfully predicted the comet’s 1933 return.
From 1920 she served as Danish editor of Nordisk Astronomisk Tidsskrift and sat on the board of the Astronomical Society. After Strömgren’s death in 1947 she succeeded him as chairman of the society (sometimes referred to as the Nordic Astronomical Society) and held the post until her own death. She also became director of the International Astronomical Union’s telegram bureau and editor of its Circulars, the official channel for reporting new astronomical discoveries worldwide. In 1931 she was elected a Fellow of the Royal Astronomical Society in London.
In 1939 she received the Tagea Brandt Rejselegat, a travel grant awarded to women of distinction in the arts or sciences. She used it for study visits to Japan and the United States. When war broke out she remained in America, working at Lick Observatory on Mount Hamilton under the University of California and holding a Martin Kellogg Fellowship. During these years she also conducted research on double stars. In 1940 the American Astronomical Society awarded her the Annie J. Cannon Award in Astronomy, then the highest honour given to a woman astronomer. In 1941 the Finnish astronomer Liisi Oterma named the newly discovered minor planet 1544 Vinterhansenia in her honour.
Vinter Hansen returned to Denmark in the autumn of 1945 and resumed her duties at the Østervold observatory. She later oversaw publications such as the long-running Københavns Universitets Almanak and helped supervise the planning of the new Brorfelde Observatory. From 1958 she served as departmental head. In 1956 she was appointed Knight of the Order of the Dannebrog. She published numerous papers in Danish and international journals and was regarded as an exceptionally careful observer and an outstanding numerical computer.
Beyond astronomy she was active in the Danish women’s movement. She served as international secretary of Danske Kvinders Nationalråd from 1929 to 1936 and sat on the executive committee of Danske Kvinders Erhvervsråd. She later established a foundation that awards travel grants to students of astronomy, mathematics and geology.
Julie Vinter Hansen died of heart failure on 27 July 1960 in Mürren, Switzerland, a mountain village in the Bernese Oberland that she loved and visited for her birthday. She was only days away from official retirement. She was buried at Vestre Kirkegård in Copenhagen.
Her career opened institutional doors that had been closed to women. She was Denmark’s first academically qualified woman astronomer, the first woman civil servant at the University of Copenhagen, and Europe’s first woman observatory observer. Her meticulous orbital work set standards for later comet and asteroid studies, while her editorial and organisational roles kept Nordic and international astronomical communication functioning through decades of change. The asteroid that bears her name remains a lasting astronomical memorial.