Alnilam nebulae: IC423-424-426 and LBN 935 

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This star field is between two famous stars: Alnilam (below) and Mintaka (out of field, above). There stars are respectively the central and right components of the Orion belt. North is toward top-left. The field is very interesting because of many faint nebulae, mainly blue colored. They are really faint and here I've acquired more than 7 hours exposure in a single night.
Here is a list of the main objects:
An interesting paper describing the area is Ogura, Sugitani, "Remnant Molecular Clouds in the Ori OB 1 Association", Publ. Astron. Soc. Aust., 1998, 15, 91-8.

Technical Data
Optics TEC 140
Focal Length
1011 mm
Focal Ratio f/7.2
Exposure Time 7h10m (single exp of 10 min)
CCD Canon EOS 5D with Baader filter
Sensitivity 800 ISO
Location Bogli (PC, Italian Apennines) at 1350 m height
27-28 December 2011
Mount Gemini G-41
Tracking Lodestar on an 80mm f/5 refractor
Temperature and humidity T= -3°C, RH=70%
Sky brightness at zenith (with SQM-L) 21.3 mag/arcsec^2
Notes Low noise thanks to a dark sky and cold temperatures.

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