Wikipedia-

NGC 2174 (also known as Monkey Head Nebula or Sh2-252) is an H II emission nebula located in the constellation Orion and is associated with the open star cluster NGC 2175. It is thought to be located about 6,400 light-years away from Earth. The nebula may have formed through hierarchical collapse.

There is some equivocation in the use of the identifiers NGC 2174 and NGC 2175. These may apply to the entire nebula, to its brightest knot, or to the star cluster it includes. Burnham's Celestial Handbook lists the entire nebula as 2174/2175 and does not mention the star cluster. The NGC Project (working from the original descriptive notes) assigns NGC 2174 to the prominent knot at J2000 06h 09m 23.7s, +20° 39' 34" and NGC 2175 to the entire nebula, and by extension to the star cluster. Simbad uses NGC 2174 for the nebula and NGC 2175 for the star cluster.

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 infrared wavelengths due to the radiation.

Location & Date	Backyard, Abbott Observatory- Long Island, NY,  Dec. 15-16, 2023
Telescope	Askar FRA400 F/5.5 Quintuplet Petzval Astrograph, ZWO focuser, iOptron GEM45G mount Image scale 1.93 arcsec/pixel
Camera	Player One Poseidon-M Pro Antlia  Ha (4.5nm) & SII OIII 3nm Pro filters Sensor temp -15°C
Exposures	Ha-18x5m SII-18x5m OIII-18x5m Bin 1x1  Gain=0 Offset=20
Planning & Acquisition	Sequence Generator Pro
Processing	Astro Pixel Processor - calibration, stacking Photoshop  2024 - HSO combine RC-Astro- Star xTerminator, Noise xTerminator

Initial stretch of 1 1/2 hours of Hydrogen Alpha (Ha) taken with Antlia 4.5nm filter.

Initial stretch of 1 1/2 hours of Sulfur (SII) taken with Antlia 3nm filter

Initial stretch of 1 1/2 hours of Oxygen (OIII) taken with Antlia 3nm filter