Integrated Flux Nebula around Polaris

Integrated Flux Nebulae (IFN) are very faint nebulae located far away from the galactic plane. They are not illuminated by a single nearby light source such as a star or a star cluster, but by the overall flux from all the Milky Way’s stars (hence the name “integrated flux”). Unobservable to the naked eye, they can be detected in long-exposure images of some areas of the sky. The most prominent IFN complex is the one located at far northern declinations, which makes it visible only in the northern hemisphere. The northern IFN sports some higher intensity areas, one of which is the well-known area around galaxies M 81 and M 82 in the Big Dipper, while the other is located around Polaris.

The big plus with the Polaris IFN is its visibility year-round. However, it’s so elusive it can be imaged only from locations with very a dark sky to the north. This rules out the Apennines in Northern Italy, due to the sheer light pollution coming from the Po plain.

I had the opportunity to capture this part of the IFN from a very dark site (SQM 21.75) near Col Agnel, at 2700 m elevation on the border between Italy and France. In spite of the very dark sky, I still had to fight against gradients in the post-production phase. The image is partly spoiled by halos around the brightest stars, probably caused by some AR coating reflections, but all in all I am quite pleased with the result.

Below is my image. Tech details: 197 x 2 min. (total 6h35m), baader-modified Canon 6D DSLR  with Samyang 135 mm f/2 telephoto lens @f/2.8, 1600 ISO, Skywatcher EQ5 equatorial mount.

Integrated Flux Nebula (IFN) around Polaris


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