Sh2-261 – Lower’s Nebula in Orion
Sh2-261, widely known as Lower’s Nebula, is a faint and expansive emission nebula situated approximately 3,300 light-years away in the constellation Orion. Tucked away in the northernmost reaches of the Hunter, near the border of Gemini, this ionized hydrogen cloud offers a more subtle and sophisticated target than its famous neighbor, the Great Orion Nebula.
The nebula glows with a characteristic deep red hue, fueled by the intense ultraviolet radiation from the massive, hot blue star HD 41997. This O-type star acts as the primary engine for the region, exciting the surrounding hydrogen gas and causing it to fluoresce. Unlike many dense, compact nebulae, Sh2-261 is characterized by its delicate, wispy structures and a central “void” or darker region that gives it a distinctive, eye-like appearance—earning it the nickname the “Eye of Ra.”
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