Triangulum Galaxy in LRGB with Ha & OIII

This is my LRGB + Ha/OIII rendition of the Triangulum Galaxy (M33), captured over a multi-night integration. I built the final color image by first creating a high-dynamic-range RGB base using long (300s) and shorter (120s) exposures. Once the RGB was balanced, I blended H-alpha and OIII into the red and blue channels to highlight the galaxy’s rich star-forming regions and outer nebulosity.

The added narrowband data brings out many of the smaller HII knots and filamentary structures that don’t fully appear in broadband alone. For comparison, I included a second version of the image showing the pure RGB result without Ha/OIII, to better illustrate how much additional structure these narrowband channels contribute.

Processing included color calibration, mild noise reduction, selective enhancement of the Ha/OIII regions, and careful masking to preserve natural star colors and avoid overwhelming the broadband structure of the galaxy.