M81-82 with integrated flux nebula (IFN)

Mouse over for the main objects. Click for the high res version.

This field is usually black in standard processed images, but a hard stretch shows the faint nebulas known as flux nebula, or IFN - Integrated Flux Nebula. The name is due to the faint light reflected by the nebulas, coming from the total light flux (thus integrated) of the Milky Way stars!
Unfortunately I was able to capture only a few hours of exposure with a DSLR, and the processing was quite difficult because of low light noise and banding problem of 5D.

Technical Data
Optics Pentax 75
Focal Lenght 500mm
Focal Ratio f/6.7
Exposure Time 3h40min (single exp of 10 min)
CCD Canon EOS 5D with baader filter
Sensitivity 800 ISO
Location Capanne di Cosola (AL, Italian Appennines), at 1500 m height
25-26 Feb 2011
Mount Gemini G-41
Tracking Lodestar with a small lens of 100 mm focal length
Temperature and humidity T= - 8 °C, RH=90%
Sky brightness at zenith (with SQM-L) 21.5 mag/arcsec^2
Notes .

HTML Editing and Publishing by Lorenzo Comolli. Email me at comolli@libero.it.
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