A Three-Fold Masterpiece
The name 'Trifid' means 'divided into three lobes,' referring to the prominent dark dust lanes that split the glowing red emission nebula into sections. M20 is a rare combination of an emission nebula (red, powered by the central star HD 164492A), a reflection nebula (the blue 'top' portion), and a dark nebula (the 'gaps' between the red lobes). It is a star-forming factory located in the star-rich fields of the Sagittarius arm of our galaxy, providing a vivid example of the life cycle of stars and the diversity of cosmic dust.
Imaging Challenges
- • Low Altitude: Like Thor's Helmet, the Trifid sits low in the southern sky for northern observers, meaning you are fighting atmospheric dispersion and 'boiling' air.
- • Color Separation: It is easy to accidentally bleed the red Ha signal into the blue reflection area during processing. Keeping these colors distinct is the sign of a pro-level edit.
- • Dynamic Range: The central star system is quite bright, and the fine dark filaments within the red lobes require careful HDR processing.
M20 is home to 'stellar jets'—long, finger-like stalks of gas and dust that contain embryonic stars, visible as tiny 'spikes' in high-resolution images.