The spiral arms of our Milky Way galaxy contain a multitude
of dark clouds composed of gas and dust, mostly carbon. These
clouds absorb and block the light from stars behind them, and
so we see them silhouetted against the starry background. The
distince "S" shape in this image is Bernard 72, often called the
Snake Nebula. It is only one of several such clouds in this image.
The Snake Nebula is in the constellation Ophiuchus. It is a few
light years across, and 650 light years from earth.

Image data:
Camera: Canon 350 XT (modified)
Telescope: William Optics 66mm ZS, Baader MPCC
Exposure: 5 minutes x 13