NGC 2174

NGC 2174 (“Monkey Head Nebula”) is an H II emission nebula located in Orion. It was discovered in 1877 by French astronomer Édouard Stephan. NGC 2174 is  located about 6,400 light-years away from Earth. 

Glowing gas and dark dust do not survive well in the Monkey Head Nebula. Young stars near the center of the nebula generate stellar winds and high energy radiation that causes the nebula's material to shift into complex shapes. The nebula is primarily composed of hydrogen which glows at 656 nm (H-alpha), and also sulphur (S[II], 672 nm) and oxygen (O[II], 501 nm) can be observed.

Emission nebula NGC 2174. Composite of 3 narrowband filter exposures: [SII] (yellow), H-alpha (green) and [OIII] (blue). These narrowband filters transmit at wavelengths of 672 nm, 656 nm and 501 nm with half width of 12 nm, respectively. 31 January and 01 February 2025, , Kempen, 

William Optics APO 110 mm, f/7, ASI1600mm pro, gain 139, T = -10C, H-alpha 7800 s, [SII] 7800 s, and [OIII] 7680 s

Image processing with PixInsight V.1.8.9

Emission nebula NGC 2174. 

Top: Composite of 2 narrowband filter exposures: H-alpha (red) and [OIII] (blue). 31 January and 01 February 2025, , Kempen, 

William Optics APO 110 mm, f/7, ASI1600mm pro, gain 139, T = -10C, H-alpha 7800 s, and [OIII] 7680 s

Bottom: Composite of 2 narrowband filter exposures: S[III] (red) and [OIII] (blue). 31 January and 01 February 2025, , Kempen, 

William Optics APO 110 mm, f/7, ASI1600mm pro, gain 139, T = -10C, S[III] 7800 s, and [OIII] 7680 s

Image processing with PixInsight V.1.8.9

Emission nebula NGC 2174. 

Top left: H-alpha 7800 s, Top Right: S[III] 7800 s, Bottom left:  [OIII] 7680 s

31 January and 01 February 2025, Kempen, William Optics APO 110 mm, f/7, ASI1600mm pro, gain 139, T = -10C, 

Image processing with PixInsight V.1.8.9