IC1396: A Dual Narrowband Journey Through 13 Hours of Data

Astrophotography is a journey of patience, perseverance, and often, a battle with data. My recent capture of the IC1396 nebula is a prime example of this. This target, shot over 13 hours of integration time, presented a unique set of challenges, particularly in the processing phase, but the results are, I believe, well worth the effort.

The Setup and the Target

IC1396, often referred to as the Elephant's Trunk Nebula, is a vast emission nebula located in the constellation Cepheus. Its intricate structures and vibrant hydrogen-alpha and oxygen-III emission lines make it a captivating subject for astrophotographers.

For this project, I utilized a Canon R7 unmodified mirrorless camera, a versatile tool for deep-sky imaging. The dual narrowband filter allowed me to isolate the crucial H-alpha and OIII wavelengths, bringing out the detailed tendrils of gas and dust within IC1396. The imaging train consisted of a Vixen R130sf telescope with a Skywatcher 0.9 coma corrector, providing a focal length of 585mm. Guiding was handled by an SV305 Pro guide camera with a 120mm guide scope, ensuring sharp, unblurred subs.

All acquisition was performed from my backyard in a Bortle 9 zone near Philadelphia. This means battling significant light pollution, making narrowband imaging essential for isolating fainter details.

The Data and the Processing

I managed to accumulate 266 frames of 180 seconds each, totaling 13 hours of integration. This extensive integration time is crucial for pulling out the subtle details and signal from the noisy background of a light-polluted sky.

The processing workflow was as follows:

• Stacking: Performed using Siril, ensuring proper calibration with darks, flats, and bias frames.
• Initial Stretch & Clarity: Cosmic Clarity and a statistical stretch in Sette Astro were applied to reveal the faint structures.
• Noise Reduction: Noisexterminator was used in Affinity Photo to tackle the inherent noise in the data, especially important given the Bortle 9 location.
• Refinement and Integration: Pixel math in Siril was employed for further refinement, followed by a "remove stars" process and the combination of Ha and OIII data.
• Final Touches: Back to Affinity Photo for final curve adjustments, another pass of Noisexterminator for ultimate noise control, and a star recomposition to bring back the star field.

This iterative process is key to achieving a clean and detailed final image when working with challenging data. While I'm still aiming for a total of 20 hours of integration to further enhance the nebula's detail, I'm very pleased with the progress and the quality of the image captured so far.

It's moments like these, after hours of imaging and careful processing, that the universe truly reveals its breathtaking beauty.