Cosmic reflections: the splendours of the vdB catalog

A reflection nebula is created when light from a star is scattered or reflected by a nearby dust cloud. Scattered light  has a spectrum similar to that of the illuminating star, but bluer,  blue light being scattered more efficiently than longer red wavelengths. This often blue color is therefore characteristic of these nebulae.

Reflection nebulae are generally less dense than dark nebulae and have sizes that are determined by the light source: their extent is not defined by the size of the dust cloud but rather by the area over which their luminosity remains. above the detection point.

Perhaps the best-known example of a reflection nebula is the nebulosity surrounding the stars of the Pleiades.

Very photogenic when they are large enough, or sometimes associated with obscure nebulae giving very beautiful compositions, they are nevertheless sometimes very small and difficult to access in amateur photography.

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The van den Bergh Catalog of Reflection Nebulae is a  astronomical catalog  compiled by  Sidney van den Bergh in 1966 which initially had 158  nebulae . It will be extended to 159 objects two years later by René Racine.

To establish this, Sidney van den Bergh has  listed the  stars  catalogs  DM  and  CD of the Northern Hemisphere ( north of 33 °  declination  south), surrounded by reflection nebulae and visible in the red and blue photos of the  Palomar Observatory Sky Survey .

The symbol used in sky charts for the objects in this catalog is vdB followed by its object number. However  many objects have multiple names and we tend to indicate the name of the van den Bergh catalog only if there is no denomination by more well-known catalogs such as the  Messier catalog  (M), the  New General Catalog  (NGC) or the Index Catalog  (IC).

The nebulae in the catalog closest to us can be found on the  gould belt  ( star ring  of the  Milky Way about 3,000  light years  in diameter, inclined about 16 to 20  degrees  related to  galactic plane, and who  could constitute the  spiral arm  local whose  Sun  is part), and the most distant are on the  galactic disc  or on the arms of the  Sagittarius  and of  Perseus , next to the  ours .  

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Note that there is also the van den Bergh-Herbst (vdbH) catalog which includes 93  reflection nebulae , some of which consist of multiple sub-regions, for a total of 136 objects. It was developed by  Sidney van den bergh  and  William herbst  and lists the  stars  catalogs  DM  and  Southern Hemisphere CD  ( south of 33 ° of  declination  south), surrounded by reflection nebulae and visible in the red and blue photos of the  Palomar Observatory Sky Survey .

It should also be noted that there are other reflection nebulae in the northern hemosphere not listed in the vdB catalog.

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Astrophotographically speaking, reflection nebulae are sometimes large and / or superb enough to constitute the main subjects of an image, and sometimes are interesting in a composition where their often bluish and vivid color brings an interesting contrast with dark nebulae or molecular clouds. often associated, or with the deep red of ionized hydrogen in emission nebulae.

The vdB catalog presented here offers a selection of photos of vdB objects, sometimes in close-up and sometimes in a wide-field composition integrating them.

The goal this time is not to present the whole vdB catalog, so some (as little as possible) of the smaller or less photogenic ones have been deliberately left out and we can turn to the great work of the Irida Observatory. to view the complete catalog imaged by  Velimir Popov and Emil Ivanov with a 300mm Newton telescope. Some have also been grouped together, because of their lower astrophotographic interest because they are small or isolated, on images that can sometimes include up to 8 vdB catalog entries.

Others were also retained although smaller than some which were discarded, quite simply because of the photographic interest which the neighboring object can present.

As with the Messier and Caldwell catalogs presented on this site, each image is from a different astrophotographer, and a total of 85 images from 85 astrophotographers were used to illustrate 115 of the 159 objects in the catalog.

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The images were collected with the permission of the contributors (Astrobin, FlickR, personal websites ...) and have not undergone any modification, and the link to the galleries or websites of the contributors is available by clicking on their name. A brief description of the material used is given to get an idea of the size of the object and its accessibility for a particular configuration, and a brief description of the object is also given for guidance, without going into details. to make room for images.  The images are all made with amateur material (sometimes large-scale ...) and by amateurs.