Charles Messier is known for (among other things) a catalog of "Messier objects".

Neither article shows an image of "Messier's telescope", though the latter includes:

Since these objects could be observed visually with the relatively small-aperture refracting telescope (approximately 100 mm ≈ 4 inches) used by Messier to study the sky, they are among the brightest and thus most attractive astronomical objects...

Question: Which telescope(s) did Charles Messier use to catalog his 110 objects? Is the telescope (or telescopes) still around?

Note that after describing the advent (and invention) of the achromatic lens, Neil English in Figure 6.5 on page 92 in the chapter Charles Messier, the Ferret of Comets in Chronicling the Golden Age of Astronomy; A History of Visual Observing from Harriot to Moore shows the following telescope with the caption:

Fig. 6.5 A small refracting telescope by Dollond, similar to the best telescope used by Charles Messier. (Image courtesy of Wiki Commons https://en.wikipedia.org/wiki/File:Telescope_by_John_Dollond_in_VULibrary.JPG)

but this is meant as an illustrative example only.

English: 4 inch refracting telescope by John Dollond (1706-1761) (tube) and J. Ramsted (mount). London, 18th cent. White hall of the Vilnius university library https://en.wikipedia.org/wiki/File:Telescope_by_John_Dollond_in_VULibrary.JPG (click for full size)

English: 4 inch refracting telescope by John Dollond (1706-1761) (tube) and J. Ramsted (mount). London, 18th cent. White hall of the Vilnius university library

Different (obviously) but related in History of Science and Mathematics SE:


1 Answer 1


According to Kenneth Glyn Jones' book "Messier's Nebulae and Star Clusters", Messier used many different telescopes in his career, some of which are listed below, translated from Messier's 1807 "Connaissance des Temps" article "Quatrième Recueil d'Observations astronomiques de 1765 à 1769".

Telescope Type Focal Length (ft) Magnification Owner
1 Ordinary refractor 25 138
2 Achromatic refractor 10.5 120 M. de Courtanvaux
3 Achromatic refractor (Dollond) 3.25 120 Duc de Chaulnes
4 Ordinary refractor 23 102
5 Ordinary refractor 30 117 M. Baudoin
6 Campani refractor 64 M. Maraldi
7 Gregorian refractor 6 110 M. Lemonnier
8 Gregorian refractor 30 104
9 Newtonian refractor 4.5 60
10 Newtonian refractor 1 44 M. de Saron
11 Refractor 19 76 Paris Observatory

According to Owen Gingrich, Messier's favourite telescope is not listed above, and was a 32 ft Focal Length FL, 7.5-inch aperture Gregorian reflector with magnification 104x.

I cannot find any mention that any of Messier's telescopes survive, but lots of other 18th century French telescopes are around, e.g. here or here, so it is possible a telescope used by Messier may still survive somewhere.

  • 1
    $\begingroup$ Thanks this is wonderful! For astronomical observations the aperture is an important parameter, I'm surprised that magnification was available but aperture diameter wasn't! Also Messier did a lot more than catalog his 110 objects, so could it have been possible that that work was done with a much more limited set of instruments? $\endgroup$
    – uhoh
    Commented Apr 8, 2023 at 18:12

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