NGC 2170

NGC 2170 is a reflection nebula located within the Monoceros R2 star-forming complex. It does not emit its own light, but instead reflects and scatters the light of recently formed, hot stars embedded within its dust clouds.

You can find NGC 2170 in the constellation Monoceros, which is situated near the prominent winter constellation Orion. It lies at a distance of roughly 2,400 to 2,700 light-years from Earth.

Because it is a reflection nebula composed of faintly lit dust, NGC 2170 is quite dark and difficult to spot visually. Most amateur astronomers capture it using long-exposure astrophotography rather than observing it directly through an eyepiece.

The striking blue hue is caused by interstellar dust grains scattering the blue light from nearby hot stars more efficiently than red light. This physical effect, known as Rayleigh scattering, is the exact same phenomenon that makes Earth's sky appear blue.