Barnard 138 is the Black Lizard, a large dark nebula located in the constellation of Aquila.

B138 was cataloged by E. E. Barnard in 1919.

His notes describe it as a "Great curved, semi-vacant lane over 3° in length. This great curved 'lane' extends from a = 19h 12m, d = -1°.6, its concave side to the east. Perhaps its most striking feature is the definiteness of its eastern outline. To the west it is less definite, and in the southern half it consists of dark branching structures which blend into a part of the Milky Way relatively dimmer than that to the east. The stars embraced by the curve to the east are much brighter or coarser than those to the west. The southern end terminates in the small black spot, B 139."

The small globular cluster at upper right in the frame is NGC 6760. It shines at an apparent magnitude of 9.1 and has an apparent size of 3.5 arcminutes.

North is to the top in the above image.

Barnard 138 Catalogs: Barnard 138 Common Name: Black Lizard Object Type: Dark Nebula Size: 180' x 60' Constellation: Aquila Image Field Centered At: RA: 19h 18m 02s Dec: +00° 03' 18"