Nebulae glow because their gases are ionized by energetic stars or stellar remnants. This ionization causes atoms to emit light at very specific wavelengths, known as emission lines.
Narrowband filters target these lines: H-alpha from hydrogen, OIII from doubly ionized oxygen, and SII from ionized sulfur. Each line corresponds to different physical conditions and chemical elements in the nebula.
By isolating these emissions, astrophotographers and astronomers can study the structure, composition, and dynamics of nebulae, turning beautiful images into scientific insights.
