Trifid Nebula Captured Under Challenging Bortle 8/9 Skies

Astrophotography often conjures images of pristine, dark skies, far from the glare of urban light pollution. However, dedicated amateurs are constantly pushing the boundaries, and the results can be nothing short of breathtaking. Today, we're diving into a remarkable capture of the Trifid Nebula, achieved from skies with a Bortle 8/9 classification – a testament to perseverance and skillful processing.

The Challenge of Light Pollution

Bortle 8 and 9 skies are considered the most light-polluted, characterized by a pervasive orange glow from streetlights and other artificial sources. Capturing faint celestial objects like nebulae in such conditions presents a significant hurdle. The ambient light can easily drown out the subtle details of distant galaxies and gas clouds, making traditional long-exposure techniques difficult.

Equipment and Acquisition

Despite the challenging environment, the astrophotographer utilized a specific setup to tackle the Trifid Nebula:

• Telescope: IEXOS 100 mount with an AT60 ED telescope.
• Filter: Antlia Triband filter, a crucial tool for isolating specific wavelengths of light emitted by nebulae, thus helping to cut through light pollution.
• Camera: Playerone Saturn (uncooled, even at a warm 32°C).
• Integration: A total of 10 hours of integration time, using 30-second sub-exposures.

While the final image is heavily cropped, impacting its raw resolution, the dedication to gathering a significant amount of data is evident.

The Processing Pipeline

Achieving a detailed image from light-polluted skies relies heavily on sophisticated processing. The following software was employed:

• Stacking & Initial Processing: Siril and GraXpert were used for stacking the sub-exposures and performing initial noise reduction and stretching.
• Advanced Processing: Seti Astro Suite, Affinity, and Darktable were then used to further refine the image, bringing out the intricate details of the Trifid Nebula and managing the remaining noise and color casts inherent to shooting under such conditions.

A Look at the Trifid Nebula

The Trifid Nebula (M20) is a fascinating object located in the constellation Sagittarius. It's a unique combination of a bright emission nebula (the red part), a dark dust cloud (giving it its name, meaning 'divided into three'), and a blue reflection nebula.

This capture, despite the environmental challenges, showcases the vibrant colors and structural complexity of the Trifid Nebula. It serves as an inspiration to fellow astrophotographers, demonstrating that with the right equipment, filters, and a robust processing workflow, beautiful deep-sky images can be obtained even from urban or suburban locations.

Have you ever tried capturing deep-sky objects from light-polluted skies? Share your experiences in the comments below!