Reflection- and Dark Nebulae

Other astronomical objects

Reflection Nebulae

Reflection nebulae are vast interstellar clouds of gas and dust that do not emit their own light. Instead, they become visible by reflecting and scattering the light of nearby stars — like cosmic mirrors in the darkness of space.

Key Characteristics

  • Composed mainly of fine dust particles (similar to soot or silicate dust).
  • Not hot enough to emit light on their own.
  • Often appear bluish, as shorter wavelengths are scattered more efficiently.
  • Extremely cold, only a few tens of Kelvin above absolute zero.

Well-Known Examples

  • M45 – The Pleiades (Seven Sisters)
  • NGC 1435 (Merope Nebula)
  • vdB 141 (The Ghost Nebula)

In short:
Reflection nebulae are cosmic “dust mirrors” that reveal themselves through the light of nearby stars.

Dark Nebulae

Dark nebulae are dense clouds of interstellar gas and dust that obscure the light of objects behind them, appearing as dramatic dark silhouettes against the glowing backdrop of the Milky Way.

Key Characteristics

  • Primarily composed of cold molecular hydrogen (H₂) and dust.
  • Very low temperatures (~10–20 Kelvin).
  • Do not emit visible light — they block it.
  • Often serve as stellar nurseries where new stars and planetary systems are born.

Well-Known Examples

  • The Horsehead Nebula (Barnard 33)
  • Barnard 68

Comparison

  • Reflection nebulae → scatter light (bluish appearance)
  • Emission nebulae → emit their own light (reddish glow)
  • Dark nebulae → block light (dark silhouettes)

external links
Wikipedia: Reflection Nebula
Wikipedia: Dark Nebula
Wikipedia: Molecular Cloud

The colorful nebula complex in the left part of the image is the Angel Nebula in the constellation Monoceros. To its right are the bluish reflection nebulae VdB 72 and VdB 73.
The Ghost Nebula on the left was cataloged by Sidney van den Bergh in 1966 as vdB 141. The embedded stars illuminate the nebula with a brownish light. The bright Iris Nebula at the upper right is illuminated by the hot star HD200775. Both reflection nebulae are located in the constellation Cepheus.
The Iris Nebula (also known as NGC 7023 and Caldwell 4) is a bright reflection nebula in the constellation Cepheus.
The reflection nebulae Messier 78 on the right and NGC 2071 on the lrft in the constellation Orion.
The open star cluster Messier 45 (Pleiades) is surrounded by bluish reflection nebulae and faint molecular clouds. The Baby Eagle Nebula LDN777 is visible in the upper right.
IC 2087 is a small emission nebula in the center of the dark nebula Barnard 22. This is part of the Taurus molecular cloud.
Large amounts of interstellar matter can be found in the Cepheus/Cassiopeia region. Here also lies the little-known dark nebula LDN 1251 from the Lynds catalog of dark nebulae.
Van den Bergh 126 and van den Bergh 134 are 2 blue reflection nebulae in the constellation of Vulpecula, surrounded by numerous dark nebulae, in the arrangement of which the silhouette of Nessie can be seen.
A reflection nebula in the constellation Perseus, the Embryo Nebula NGC 1333 is a vast star-forming region of young stars less than a million years old.
The dust cloud Sh2-73 illuminated by the light of the Milky Way between the constellations Hercules (top left) and the northern crown (Corona Borealis)
The Cosmic Hairpin (Sh2-73) is a dust cloud in the constellation Hercules illuminated by the light of the Milky Way. Nebulae of this type are also known as galactic cirrus clouds.
The Cocoon Nebula IC 5146, upper right, is a star-forming region with the embedded open star cluster Collinder 470 in the constellation Cygnus. IC 5146 is located at the end of the elongated dark cloud Barnard 168 and, together with it, is part of an extensive dust cloud.
Barnard's Dark Nebula B142 and B143, also known as the E Nebula, are located in the constellation Eagle (Aquila) and in an area of ​​enormous abundance of stars.
Lynds Dark Nebula (LDN673) is a molecular cloud complex in the constellation Aquila, in the so-called Aquila Rift
In the left part of the image is the reddish emission nebula Sh2-92, in the right part the dark nebulae LDN 796, 799, 800, 803, 804, 806, 807, 808 and 812
In the constellation Pegasus is the barred spiral galaxy NGC 7497 surrounded by the molecular cloud MBM 54.
LBN 438 (Lynds' Catalog of Bright Nebulae) in the constellation Lizard is part of Lacerta OB1, a vast star-forming region. It is about 1200 light-years from Earth.
Barnard 150 is a dark nebula visible in Cepheus constellation. It is also known as the Seahorse Nebula due to its shape.
Emission NebulaeStar Clusters and Asterisms