Ramón María Aller Ulloa

Lore & Background

Aller Ulloa began his studies at a school owned by the Society of Jesus in A Guarda (Pontevedra) and continued at the theological seminary of Lugo. At age 20 he obtained his bachelor and doctorate in Sacred Theology and was ordained a priest within two years. In 1899 he began science studies at the University of Oviedo, finishing them at the University of Madrid in 1904, graduating with honours. His first astronomical studies began with a present from his grandmother—a monocular of 67 mm—and later a theodolite. With these simple devices he began writing home observations and mailing them to scientific publications. In 1912 the "Anuario del Observatorio de Madrid" published his first paper, "Observaciones del cometa de Joannesburgo 1910a." In 1917 he built a homemade observatory in his garden. Using an inheritance from his uncle, he acquired a refracting telescope (Steinheil, 120 mm aperture, 1800 mm focal length) and a dome to protect it. He then prepared a detailed scientific program focusing on double stars, planet surfaces, and occasional observations of eclipses, comets, and meteoroids. His scientific publications grew substantially, appearing in the German "Astronomische Nachrichten" and the French "L'Astronomie." The quality of his data led several European observatories to assume a team of researchers existed in Lalín, unaware that the data came from a single scientist in a homemade observatory.

Reader's Guide

Aller Ulloa's significance lies in his contributions to double-star astronomy from a private observatory in Lalín, Spain. He discovered four double stars (Aller 1–4) and was the first Spanish astronomer to calculate the orbit of a double star system (STT 77). His work earned him membership in the International Astronomical Union Commission 26 (double stars) in 1948 and the National Commission on Astronomy in 1949. He also designed and built devices for measurement and observation, some purchased by the Paris Observatory, and suggested modifications to the Zeiss astrograph that the manufacturer accepted without payment. He published 78 articles in European specialized publications, 4 books, and directed 5 PhD theses, three of them between 1960 and 1963 when he was 83 years old. His secondary studies included meteors, planet surfaces, auroras (describing one visible in Lalín in 1938), eclipses, transits, and biographies. A lunar crater was provisionally named "Aller" by English astronomers Hugh Percy Wilkins and Patrick Moore in their 1955 book "The Moon," but the crater was later renamed Atwood and officially adopted by the IAU in 1976.

Did You Know?

• Aller Ulloa spoke 10 languages and was recognized as a polyglot by his European counterparts.
• He received his second PhD, in astronomy, from the University of Madrid in 1943.
• He was elected a member of the Seminario de Estudos Galegos in 1928 and the Royal Galician Academy in 1942.
• A lunar crater was provisionally named 'Aller' by Wilkins and Moore in 1955, but later renamed Atwood.

From Sacred Theology to the Stars

Ramón María Aller Ulloa's path into science was anything but conventional. Born in 1878 in Galicia, he first attended a Jesuit-run school in A Guarda, Pontevedra, before moving to the theological seminary in Lugo. Remarkably, by the age of twenty he had already earned both a bachelor's and a doctorate in Sacred Theology, and within the following two years he was ordained a priest. Yet his curiosity did not end there. In 1899 he enrolled in science studies at the University of Oviedo, completing his degree with honours at the University of Madrid in 1904. His astronomical journey began modestly: a 67 mm monocular gifted by his grandmother, followed by a theodolite as a second present. With just these two simple instruments, he recorded observations from home and mailed them to scientific publications. His first paper, on the Johannesburg comet of 1910, appeared in the Anuario del Observatorio de Madrid in 1912. This humble beginning—priest, self-taught observer, and curious mind—set the stage for a career that would earn him a place among Europe's serious astronomers.

A One-Man Observatory in Lalín

In 1917, Aller Ulloa built a homemade observatory in his garden in Lalín. With the inheritance from a late uncle, he acquired a Steinheil refracting telescope with a 120 mm aperture and 1800 mm focal length, and because the equipment was too large to leave exposed, he also procured a protective dome. Once installed, he designed a rigorous programme covering double stars, planetary surface examinations, and occasional events such as eclipses, comets, and meteoroids. The output was extraordinary: his data appeared in the German Astronomische Nachrichten and the French L'Astronomie, and European observatories receiving his submissions assumed a full research team was operating in Lalín, unaware that a single priest-scientist in a garden shed was responsible. His specialisation in double stars produced four discoveries that still bear his name—Aller 1 through Aller 4—and he became the first Spaniard to calculate the orbit of a double star system, STT 77. He also invented several measurement and observation devices, including a sidereal-time clock and a base for a portable vertical-circle monocular, some of which were purchased by the Paris Observatory.

Academic Recognition and Prolific Scholarship

Aller Ulloa's institutional career accelerated in the 1930s and 1940s. Elected to the Seminario de Estudos Galegos in 1928 and to the Spanish Royal Academy of Sciences in 1939, he joined the Royal Galician Academy in 1942. In 1940 he began teaching analytic geometry and mathematical analysis at the University of Santiago de Compostela, and in 1944 the university created a dedicated chair in astronomy specifically for him. He earned a second doctorate, this time in astronomy from the University of Madrid, in 1943. His scholarly output was vast: 78 articles in specialised European publications, four books, and five directed PhD theses. Strikingly, even at eighty-three he was still supervising doctoral work—three theses between 1960 and 1963 on topics ranging from theodolite applications in geodetic astronomy to transits across vertical circles. Recognised as a polyglot who spoke ten languages, he was appointed to the International Astronomical Union's Commission 26 on double stars in 1948 in Zurich and to Spain's National Commission on Astronomy the following year. He also suggested modifications to Zeiss's astrograph production that the German manufacturer accepted and, in appreciation, declined his payment.

Legacy and the Crater That Was Not

Aller Ulloa's posthumous legacy carries a bittersweet note. In their 1955 book The Moon, English lunar specialists Hugh Percy Wilkins and Patrick Moore named a crater "Aller," placing it at 5.8°S, 57.7°E within the Mare Fecunditatis. However, the IAU later adopted the name Atwood for that same crater—honouring the English mathematician George Atwood—introducing it provisionally in 1974 and confirming it officially in 1976. The crater, 28.64 km in diameter and 2.5 km deep, thus never permanently carried his name. Nevertheless, his broader impact endures: his four named double stars remain in the catalogue, his 78 articles and four books continue to be referenced, and his inventive instruments—purchased by the Paris Observatory and refined for Zeiss—testify to a mind that bridged priestly vocation, mathematical rigour, and hands-on engineering. He died in Lalín in 1966 at the age of eighty-eight, and a museum dedicated to his memory now preserves his story.