Degree of difficulty 3 (of 5)

Minimum aperture 50mm

Designation NGC 1982

Type Galactic nebula

Class E

Distance 1300 ly (see M 42)

Size 3 ly

Constellation Orion

R.A. 5h 35.6min

Decl. –5° 16′

Magnitude 6.8

Surface brightness 22mag/arcsec2

Apparent diameter 6′×3′

Discoverer de Mairan, 1733

History Today, M 43 is regarded as just a part of M 42, but the early observers cataloged it as a separate object. In 1733, Jean-Jaques Dortous de Mairan was the first to notice the apparently separate nebula. He wrote: “Brightness around a star, similar to the atmosphere of our Sun, if it was dense and extended enough to be visible in telescopes from such a distance.” The French man was wrong about this comparison, but his thoughts reflected the ideas of his time concerning the formation of the Solar System.

Messier added M 43 to his catalog on the 4th of March 1769, the same day as the Orion Nebula. He characterized M 43 as “a small star, which is surrounded by nebulosity.” Later, in 1771, Messier included it in his drawing of the Orion Nebula. In 1783, William Herschel de- scribed M 43 as a “circular glory of whitish nebulosity, faintly joined to the great nebula.” From later observations, however, he believed that the central star in M 43 was instead located behind the nebula, shining though it like the moon through thin clouds. His son John was the first to recognize the “tail” of the nebula towards the north, and he also saw a dark division cutting into the nebula.

Lord Rosse believed that he saw a nebula with spiral structure around the star. Secchi agreed to that and likened the general shape to a mirror-image of a comma. In the 1870s, Holden observed small dark dots to both sides of the “central star.” By that time, de Mairan's nebula was long considered an integral part of the M 42 complex.