Messier's friend and colleague, Pierre Méchain, also continued his search for nebulous objects, evidently with the intention to communicate his observations to Messier for inclusion in a new revision of the Messier Catalog. When this revision did not occur, he communicated his observations of M104, M105, M106 and M107 in a letter of May 6, 1783, to Bernoulli for publication in in the 1786 Berliner Astronomisches Jahrbuch. He also reports the "nebulae" M108 and M109, which Messier had mentioned but not given an own catalog number.
These facts demonstrate that the original author and the main contributor themselves intended to extend the catalog beyond its original 103 entries; presumably this may mark the beginning of the attempts to enlarge the catalog.
M104 was more or less officially added to the catalog in 1921 by Camille Flammarion.
David Nash has found the earliest popular discussion of the objects M105 to M109 is the article by Owen Gingerich in the September, 1953 Sky and Telescope, in which he mentions the six "Méchain objects" (M104 to M109). Gingerich cites an article by Helen Sawyer Hogg in the RASC Journal, 41, p 265, (1947) as a reference for the Jahrbuch report.
Considering the efforts of Messier and Méchain of 1781 to 1783 as the beginning of attempts to extend the catalog, 1921 to 1953 may be regarded as the beginning of general acceptance thereof.
Early references containing extended versions of Messier's catalog include an early list of 109 Messier objects published in "Olcott's Field Book of the Skies", 4th ed., revised by R. Newton Mayall and Margaret W. Mayall. This came out in 1954 and lists 109 Messier objects, though M104 - M109 are noted as "not in Messier's List" and added by Helen Sawyer Hogg (M104 - 107) or Owen Gingerich (M108 and M109).
Within the next 15 years the additions became pretty widely accepted; David Levy, in his "The Sky: A User's Guide", mentions only the modern 110-object catalog and claims to have observed them all between 1962 and 1967. In 1967, Patrick Moore's "Amateur Astronomy" gives the "original" to 104 but has M105-M109 listed as an addendum. Similarly Neale E. Howard's "The Telescope Handbook and Star Atlas", also published in 1967, lists the original 103 but refers to M104 through M109 in a section devoted to observing the Messiers.
By the late 1970s this convention (modern Messier list of 109 or 110) was close to universal, showing up in just about every available guide, including the Royal Astronomical Society of Canada's Observer's Handbooks and the Webb Society Deep Sky Observer's Handbook (1981 edition). Nowadays, the modern list of 110 objects is widely accepted as the standard Messier Catalog.
This page is widely based on information provided by David Nash, whose help is gratefully acknowledged.
Last Modification: June 3, 2007