Why Doesn’t Astronomy Magazine Recognize Messier 110?

Why It Matters

Maintaining the original 103‑object list preserves catalog consistency for education and amateur observing, while highlighting how legacy decisions still shape modern astronomy resources.

Key Takeaways

• M110 observed by Messier but omitted from original catalog.
• Amateur Kenneth Glyn Jones added M110 in 1966.
• Astronomy magazine follows Messier’s original 103-object list.
• Six later objects, including M104, stem from Méchain’s notes.
• Catalog consistency impacts educational resources and amateur observations.

Pulse Analysis

The Messier catalogue, compiled by French comet hunter Charles Messier in the late 18th century, was designed as a practical list of diffuse nebulae and star clusters that could be mistaken for comets. Messier published 103 objects before his death, ending with the Andromeda Galaxy (M31). Although he recorded the companion galaxy now known as M110 during his observations, he never assigned it a Messier number, leaving it outside the official roster. This historical cutoff has shaped how astronomers and educators reference deep‑sky objects for more than two centuries.

Decades after Messier’s death, amateur astronomer Kenneth Glyn Jones revisited the original logs and, in 1966, formally introduced M110 as a supplemental entry. Parallel to this, six additional objects—most notably the Sombrero Galaxy (M104)—were later incorporated based on notes from Messier’s colleague Pierre Méchain, who discovered many of the fainter nebulae. Modern publications, including Astronomy magazine, often adhere to the strict 103‑object framework to preserve the catalog’s historical integrity, while acknowledging the practical need for expanded lists in contemporary observing guides.

The decision to exclude M110 from mainstream magazine listings has tangible effects on the amateur community. Consistent numbering simplifies star‑chart software, telescope databases, and classroom curricula, reducing confusion for newcomers. However, omitting widely recognized objects can also limit exposure to the full diversity of nearby galaxies, especially for observers targeting the Andromeda system. As digital platforms increasingly allow customizable catalogs, the debate underscores a broader tension between honoring legacy classifications and embracing a more inclusive, data‑driven approach to celestial cataloguing.