Two dark nebulae in M24 in Sagittarius

ukastronomy wrote:
Lynds' Catalogue of Dark Nebulae (LDN 327 and 323) show up well in
these two images. Of almost equal interest are the stars that are very
bright in the infra-red but almost invisible in V (green) band. Are
these stars very cool red giants or perhaps Carbon stars?.

Nice images. I expect the biggest cause of difference between the two
images is interstellar reddening. The position is less than a degree
from the Galactic plane.

Carbon stars are rare; you won't be seeing many of those.