Association of Lunar and Planetary Observers

The Association of Lunar and Planetary Observers, commonly abbreviated ALPO or A.L.P.O., is an international scientific and educational organization devoted to systematic observation of the Solar System. Established in the United States in March 1947 by Walter H. Haas, it was created to encourage astronomical work by both amateur and professional observers and to preserve observations that might otherwise lack a suitable specialist publication outlet. The organization later became incorporated in 1990 and is headquartered in Springfield, Illinois. ALPO's scope covers a broad range of Solar System subjects, including the Sun, Earth's Moon, planets, asteroids and other minor planets, meteors, meteorites, comets, eclipses, and transits. Its work combines visual observing, drawing, photography, imaging, measurement, reporting, and the use of other instruments available to nonprofessional and professional astronomers. Rather than operating as a commercial astronomy company, ALPO functions as a membership-based scientific community and coordination network. Its activities help observers organize around common targets, apply repeatable observing methods, and share records that can contribute to long-term study. The organization developed specialized sections as members concentrated on particular celestial objects and phenomena. These sections were modeled in part on the structure of the British Astronomical Association. Each section was initially led by a recorder and later by a coordinator. ALPO has maintained observing sections for the Sun, Mercury, Venus, meteors and meteorites, the Moon, Mars, minor planets, Jupiter, Saturn, the remote planets, comets, eclipses, and transits. It has also maintained special sections concerned with computing, history, publications, training, and youth programs. This structure allows the association to support both focused observing projects and broader educational and administrative functions. The Lunar Section has been one of ALPO's most active areas. Its work has included detailed drawings and records of lunar features, as well as observations of reported transient lunar phenomena. The Saturn Section, founded in 1971, is associated with Julius L. Benton, who served as its first coordinator and continued in that role for decades. Historical ALPO observers have also contributed to wider astronomical work; for example, Alika K. Herring's lunar drawings were published in Sky & Telescope, and her work helped inform assessments of astronomical seeing conditions in Hawaii alongside observations by Franklin E. Roach. ALPO's principal publication is The Strolling Astronomer, also known as The Journal of the Association of Lunar and Planetary Observers, or StAst and JALPO. Published quarterly since 1947, the journal provides a continuing archive for observational reports, technical methods, research notes, and organizational material. In its early years it helped fill a gap in planetary-science publishing before the establishment of the journal Icarus in 1962. ALPO has also issued specialized works, conference proceedings, and ALPO Monographs. Its Minor Planets Section publishes The Minor Planet Bulletin. The association holds an annual summer conference, generally in cooperation with other astronomical organizations. Through its publications, specialist sections, training activities, youth programs, online communities, and conferences, ALPO connects observers across experience levels and countries. Its continuing identity is based on collaborative Solar System observation, practical training, and the preservation and dissemination of observational records.

ALPO was founded in March 1947 in the United States by Walter H. Haas. Its original purpose was to promote systematic Solar System observation among amateurs and professionals and to provide a durable channel for publishing observations. The association began without a rigid formal structure, but the increasing specialization of its members led it to create dedicated sections for individual planets, the Moon, the Sun, minor planets, comets, meteors, eclipses, and related subjects. The section-based model was influenced by the organizational approach of the British Astronomical Association. Early section leaders were known as recorders; the title later changed to coordinator. The Saturn Section was established in 1971, with Julius L. Benton as its first coordinator. The Lunar Section became another major area of activity, maintaining detailed observations and drawings of lunar features and recording reports of transient lunar phenomena. Work by ALPO observers also intersected with wider astronomical practice, including the documentation of lunar features and the assessment of observing conditions. From its beginning, publication was central to the association's identity. Haas established The Strolling Astronomer, later titled The Journal of the Association of Lunar and Planetary Observers, to create an archive for systematic observations at a time when existing journals did not adequately serve that community. The quarterly periodical has continued from 1947 and is commonly identified by the abbreviations StAst and JALPO. ALPO later expanded its publication activity through specialized material, conference proceedings, and ALPO Monographs. The Minor Planets Section publishes The Minor Planet Bulletin. As its activities expanded, ALPO added special sections covering computing, history, publications, training, and youth programs alongside its observing sections. These areas reflect the association's dual scientific and educational mission. It supports not only the collection of observations but also the development of observing skills, the organization of historical records, and participation by younger astronomers. The organization was incorporated in 1990. It remains headquartered in Springfield, Illinois, and continues to operate as an international association. Its activities include specialist observing programs, publication of observational material, online member communication, and an annual summer conference often held with other astronomical groups. ALPO's historical contribution lies in building a durable structure through which amateur and professional observers can coordinate Solar System studies and make observations available to the broader astronomical community.

• 1990

  Organization incorporated

  [1]Association of Lunar and Planetary Observersen.wikipedia.org

  ALPO became an incorporated organization.

• 1971

  Saturn Section established

  [1]Association of Lunar and Planetary Observersen.wikipedia.org

  ALPO created its Saturn observing section, with Julius L. Benton serving as its first coordinator.

• 1947

  Association founded

  [1]Association of Lunar and Planetary Observersen.wikipedia.org

  Walter H. Haas established ALPO in the United States in March 1947 to advance coordinated Solar System observation by amateur and professional astronomers.

• 1947

  The Strolling Astronomer begins publication

  [1]Association of Lunar and Planetary Observersen.wikipedia.org

  ALPO began publishing its quarterly journal, creating a continuing archive for observational reports and technical astronomical work.

A specialist international astronomy association positioned at the intersection of amateur observing, professional research support, scientific education, and long-term documentation of Solar System phenomena.

• Scientific journal · 1947

  The Strolling Astronomer

  ALPO's quarterly periodical, also known as The Journal of the Association of Lunar and Planetary Observers and by the abbreviations StAst and JALPO. It publishes observational reports, methods, research notes, and association material. The journal has appeared continuously since 1947 and was created to preserve specialist Solar System observations in a formal publication.

• Astronomical bulletin

  The Minor Planet Bulletin

  A publication associated with ALPO's Minor Planets Section. It disseminates material relating to observations and studies of minor planets, extending the association's publication work beyond its general journal.

• Specialist astronomy publications

  ALPO Monographs

  A series used for specialized astronomical works and, on occasion, conference proceedings. The monographs complement the regular journal by providing space for focused subjects and longer-form material.

• Scientific observing program

  Solar System observing sections

  A network of specialist sections covering the Sun, Mercury, Venus, meteorites, meteors, the Moon, Mars, minor planets, Jupiter, Saturn, the remote planets, comets, eclipses, and transits. Coordinators organize observations, encourage consistent methods, and support the exchange of results among participants.

• Astronomy education

  Training and youth programs

  Special sections and activities intended to develop observing skills and broaden participation in astronomy. They form part of ALPO's educational mission alongside its scientific observing and publication programs.

1. 1Association of Lunar and Planetary Observersen.wikipedia.org
2. 2Association of Lunar and Planetary Observers official websitealpo-astronomy.org