Barnard 72 is the famous "Snake" or "S" dark nebula in Ophiuchus.

It is a concentration of obscuring dust and dark matter in space that is opaque and doesn't let the stars behind it show through. Below and to the right of the Snake is B68, an extremely dense dark nebula, and to the lower left of it are B69, B70 and B71.

These dark nebulae get their name from pioneer astrophotographer Edwin Emerson Barnard, who cataloged many of them photographically, publishing a list in the 1919 paper in the Astrophysical Journal, On the Dark Markings of the Sky with a Catalogue of 182 such Objects.

Barnard also published the wonderful book A Photographic Atlas of Selected Regions of the Milky Way in 1927 with pictures of many of the dark nebulae that he discovered. B72 is on plate 19 of the Atlas.

• Lens: Astro-Physics 130EDT f/8 Triplet Apochromatic Refractor
• Focal Length: 780mm
• Focal Ratio: f/6 with Astro-Physics 0.75x Telecompressor Field Flattener
• Exposure: 7 x 8 minutes = 56 Minutes Total Exposure
• Mount: Losmandy GM100EQ German equatorial mount
• Guiding: ST-4 autoguided with SV70ED guidescope
• Camera: Modified Canon EOS 1000D (Digital Rebel XS) DSLR
• Mode: Raw
• ISO: 1600
• White Balance: Custom
• In-Camera Noise Reduction: Off
• Filter: Astronomik CLS filter
• Time: 1:30 a.m. EDT
• Date: June 11, 2010
• Location: Steelmantown, NJ
• Temp: 67F
• SQM Reading: 20.80
• Relative Humidity: 76 percent
• Seeing: NR
• Clouds: In and out
• Dew: NR
• Wind: Some
• Transparency: NR
• Calibration: Master Dark made of 24 x 10-min 60F subs, Master Bias made of 24 60F subs, calibrated in Images Plus
• Processing: Aligned, stacked in Images Plus, corrected and enhanced in Photoshop CS2