- Barnard 72 The Snake Nebula
Barnard 72 is a curiously shaped dark nebula lying within the stream of the Summer Milky Way in the constellation Ophiuchus. Its sinuous shape has given it the name of the Snake Nebula. This object is visually located only 7 degrees from the Galactic Center in neighboring Sagittarius. My image is a fairly long exposure, so the nebula stands out from the multitude of tiny stars making up the Milky Way stream in this region. It is the combined light from these countless stars that gives us the glowing stream of the Milky Way that we see with our naked eye on Summer nights. The tiny stars in my image appear reddened due to their distance and the attenuation of their light (primarily in the blue spectral band) by intervening dust.
There are several smaller dark nebulas located just below B 72. These smaller nebulas have been called the "Snake's Eggs". From right to left, they have the designations B 68, B 69, B 71, B 70, and B 73. The larger dark nebula along the left side of my image (next to the bright star) is B 74. The ability of the interstellar dust comprising these nebulas to block starlight is remarkable, considering that the nebulas contain only a few dust grains per cubic meter. In particular, B 68 is completely opaque to the light from the stars behind it. This whole region abounds in dark nebulas of various shapes and sizes.
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