This image of the Eagle Nebula (M16) presents an uncommon narrowband approach by isolating only sulfur (SII) and oxygen (OIII) emissions, deliberately excluding hydrogen-alpha.
Emission nebulae are typically imaged using broadband light, Hα–OIII combinations, or full SHO palettes. In this case, removing hydrogen-alpha allows the structure of the nebula to emerge from the interaction between sulfur and oxygen alone.
Oxygen dominates the ionized regions, producing smooth blue tones and revealing the volume of gas shaped by stellar radiation. Sulfur, often associated with denser material and shock fronts, traces the edges of structures, outlining transitions and giving definition to features such as the Pillars of Creation.
Without the overwhelming contribution of hydrogen-alpha, this view offers a different perspective on the Eagle Nebula, emphasizing geometry, contrast, and the balance between its main emission components.
Gear:
Telescope: GSO 8″ Imaging Newtonian
Camera: Touptek ATR2600C at -10ºC
Mount: HEQ5 Pro
Filter: Askar Colour Magic D2 (SII + OIII)
Guiding: Askar FMA135 + ASI220MM Mini
8 hours of integratio time (60 x 480s)
50 Darks, 50 Skyflats and 50 Darkflats
Loication: Vitória – ES, Brasil
Date: 29.6.2025