Two dark nebulae in M24 in Sagittarius

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. These
stars must be very cool red giants?.

Lynds' Catalogue was based on a study of the red and blue prints of
the National Geographic - Palomar Observatory Sky Atlas. The catalogue
contains positions for the centers of dark nebulae or clouds found by
Lynds, the cloud sizes in square degrees and visual estimates of their
opacity. Many make excellent targets for the amateur astronomer.

http://www.martin-nicholson.info/baa/darkregions2.htm


Martin Nicholson, Daventry, England.

My website is at http://www.martin-nicholson.info/1/1a.htm
My informal Astronomical Blog is at http://ukastronomy.livejournal.com/