The Lagoon Nebula (Messier 8, NGC 6523), is a star-forming region located around 5-6 thousand light years away in the Sagittarius-Carina arm of the Milky Way. At magnitude 6, it is the only star-forming region aside from the Orion Nebula that is visible to the naked eye from northern latitudes. The western half of the Lagoon is illuminated by 9 Saggitarii, an extremely hot spectral class O5 star that is 23,000 times brighter than our sun in visible light, yet is still 44 times brighter in ultraviolet, than it is in visible wavelengths. That ultraviolet light ionizes the hydrogen clouds that comprise the visible parts of the nebula. When the absorbed energy is released by the hydrogen returning to a relaxed state, the energy is released as lower-energy visible light. Most is released as red light (H-alpha), and the remainder as blue (H-beta).

The Lagoon has already produced an open cluster of about 30 young stars (NGC 6530), visible just to the left of the largest dark dust lane, which illuminates the eastern half of the nebula. At roughly 90x40 arc-minutes, the Lagoon Nebula covers an area just over 3 times the size of the full moon.

Equipment:

-William Optics Zenithstar 73mm FPL-53 doublet APO refractor.

-William Optics Flat73r focal reducer/field flattener.

-SkyWatcher EQ6R-Pro equatorial mount.

-ZWO ASI533MC-Pro color camera with ZWO luminance filter.

-William Optics Uniguide 32mm guide scope.

-ZWO ASI462MC color camera with Antlia 685nm IR-pass filter.

-ZWO ASIair Pro.

Pre-processing/Calibration performed in DeepSkyStacker:

-21 120-second lights (gain 0), calibrated with temperature matched darks, flats, and bias frames (30/60/60 at 0 degrees Celsius).

-Debayered with Auto Homogeneity Directed interpolation.

-Stacked with Auto Adaptive Weighted Average algorithm.

-Export to 3-plane FITS.

Post-processing performed in Siril:

-Crop.

-Background Extraction.

-Photometric Color Calibration.

-Histogram Transformation.

-Export to TIFF.

Final image adjustments performed in GIMP:

-Noise reduction (NR, gaussian blur, Selection tools).

-Fine tune colors (Curves, Saturation, Selection tools).

-Histogram adjustment (Curves, Levels, Selection tools).

-Sharpening (lighten only/darken only).

-Export to PNG.