Capturing the Celestial Bubble: An Astrophotographer's Journey with NGC 7635

Cosmic clouds of gas and dust often paint the night sky with ethereal beauty, and the Bubble Nebula, NGC 7635, is a prime example. This stunning celestial object, a giant bubble of ionized gas surrounding a massive star, has been beautifully rendered in a recent astrophotography endeavor.

The Equipment and the Shot

The image was captured using a ZWO Seestar S50, a versatile telescope designed for astrophotography, in alt-az mode. The setup utilized the included tripod, ensuring a stable platform for long exposures. To enhance the capture of specific light wavelengths, the internal duoband "lp" filter was employed.

The exposure settings were set at 3192 individual frames, each with a duration of 10 seconds. This significant number of sub-exposures is crucial for gathering enough light and detail to reveal the intricate structures within the nebula.

Bringing the Data to Life: The Processing Pipeline

Post-processing is where the raw data truly transforms into a captivating image. The captured frames were stacked using Siril, a popular open-source astrophotography software. An average stacking method was used with rejection to minimize noise and artifacts, ensuring a clean foundation for further refinement. Importantly, no drizzle integration was applied in this stage.

The subsequent processing steps involved several key adjustments to bring out the nebula's characteristics:

• Background Extraction: This step meticulously removed unwanted background light and gradients, making the fainter details of the nebula more apparent.
• Asinh Stretch: An arcsine hyperbolic stretch was applied to enhance the contrast and bring out a wider range of faint details without blowing out the brighter areas.
• Histogram Stretch: Further manipulation of the histogram helped to balance the tonal range of the image, ensuring that both highlights and shadows were well-represented.
• Curve Adjustment: Fine-tuning of the color and brightness curves allowed for precise control over the final appearance of the nebula, accentuating its vibrant colors and intricate structures.
• Star Reintegration and Stretching: Finally, the stars were reintegrated and stretched to ensure they complemented the nebula's details without overpowering them. This crucial step balances the visibility of the stars with the delicate features of the nebula.

This comprehensive approach, from careful acquisition to meticulous processing, has resulted in a truly spectacular view of the Bubble Nebula, showcasing the power of modern astrophotography in unveiling the wonders of the universe.