De Mairan's Description of "Nebulae"

Reference:

• Traite physique et historique de l'Aurore Boréale. Par M. de Mairan. Suite des Mémoires de l'Académie Royale des Sciences, Année M.DCCXXXI [Physical and historical treatise of the Aurora Borealis. By M. De Mairan. Series of the Memoirs of the Royal Academy of Sciences, for the year 1731]. Royal Printing Office, Paris, 1733. Pp 259-263 & plate XV after p. 298.

On the Atmospheres of some fixed Stars.

The comparative anatomy is never more useful, than to exercise in some deformed part of man, or the animals: It is this what usually reveals a structure & a mechanism which completely escapes us otherwise. Shouldn't it be the same with comparative Astronomy? Despite the admirable uniformity which reigns in the operations of Nature, the Universe has its misfits in the large as in the small. This innumerable quantity of fixed Stars visible to the naked eye, & with the help of telescopes, present to us as many Suns similar to the one in the center of our Whirl:

More to come ..

[M31]
The first appearance of this nature which was noticed in the Sky, was, if I'm not mistaken, the Andromeda Nebula. The discovery of it is attributed by famous Authors [Halley] to M. Bouillaud, in 1661; but it is well older, & actually belongs to Simon Marius who noticed this Star in 1612, three or four years after the invention of Telescopes.

[More Nebulae]
Since, there have been found more other, similar appearances, & which are more or less in relation to the preceding:
[M22]
Made 1. A very small patch, but very luminous, & which ejects a ray between the head & the Bow of Sagittarius, in 1665, by a German named Abraham Ihle.
[Omega Centauri]
2. Another one in Centaurus, in 1677, by M. Halley, while he compiled the Catalog of Southern Stars.
[M11]
3. A patch which is close to the Northern foot of Ganymede or Antinous, discovered by M. G. Kirch, in 1681, & reported with a Figure, in the Appendix of his Ephemerides. It is a small cloud, very dense & very similar to the Nebula in Andromeda, yet unlike the latter, it lets see a Star which is close to its Center. Also M. Kirch was first in doubt if this wasn't a Comet.
[M13]
4. Another one finally, in the Constellation of Hercules, in 1714, by M. Halley.

[LMC/SMC]
I will not speak at all about the other small, obscure patches which have been seen, by accident, near some Planet when it was observed, but couldn't be recovered since, because of the lack of a fixed object which would lead back the Observer. Maybe it is also necessary to include into the same class the two cloudy patches which the Father de Beze, a Jesuit, noticed in 1689, near the South [Celestial] Pole, different from the two other, brighter ones, which are usually drawn on the [celestial] Globes, & which are known by the name of the Large & the Small Cloud.

[M42]
But I will not silently pass by the luminous Space which M. Huygens discovered in 1656, around the Orion Nebula, that brightness in an irregular Figure, less blue & less dark than the rest of the Sky. It appears, according to someone, as a piece of , or according to others, as a hole made in the celestial vault, & through which one notices a Light which that vault doesn't have. This space contains seven Stars, over a length in Declination of 5 to 6 minutes of arc, and over a width in [Right] Ascension of 3 or 4 [arc min].

More to come ..

[M43]
Finally I will add that close to the luminous space in Orion [M42], one sees the star d of Huygens [NU Orionis] currently (1731) surrounded by a brilliance very similar to that which produces, as I believe, the atmosphere of our Sun, if it were dense enough & extensive enough to be visible in Telescopes at a similar distance. See it in the form & the situation [given by] D, according to what was determined with the Reticule.

Figure XXVII represents these objects reversed, & such as they have appeared to me mostly since five to six years, with a Refractor of 18 & of 22 feet [FL]. I have turned into the same [orientation] the [figure] XXVI which is thius in the sense contrary to that of M. Huygens.

The Milky Way, seen with the same Telescopes, has appeared to me not to be in a multitude of places, as a stuff similar to a luminous space spangled with small [faint] Stars, like that of Orion.

Translation from French by Hartmut Frommert

Last Modification: May 24, 2002