PixInsight & Photoshop CS6.
eXcalibrator v5.0 for
color balancing, using 307 stars from the SDSS-DR9 database.
processing includes calibration, registering, stacking, LRGB
creation, gradient removal and non-linear stretching
with HistogramTransformation .
Noiseware 5, a
final touch up.
North is to the
At the image bottom is
the blue reflection nebula, Cederblad 201 . The extended dark nebula
is cataloged as Barnhard 175. Together, they are known as Van den
Bergh 152, in the constellation Cepheus.
To the upper left is the ancient planetary nebula Dengel-Hartl 5.
The red filaments, extending to the image bottom, are part of the
huge supernova remnant SNR 110.3+11.3. These two red objects give a
wonderful contrast to the beautiful chocolate color of Bernard 175.
Max Wolf's assistant,
August Kopff, photographically discovered the complex structure on
October 21, 1908. To Wolf, it looked like a cave and he started
calling it the Cave Nebula. Wolf also thought the nebula was an
actual cave formation in the Milky Way stars. It was finally
designated as vdB 152 and is still sometimes called Wolf's Cave.
Here is Max Wolf's
Dec. 1908 announcement
in the Monthly Notices of the Royal Astronomical Society, Vol. 69,