NGC 7635: Capturing the Bubble Nebula from Bortle 8 Skies

Astrophotography is often about pushing boundaries, reaching for targets that test our equipment and skills under less-than-ideal conditions. Today, we're diving into the fascinating capture of NGC 7635, more commonly known as the Bubble Nebula.

This particular image represents a significant challenge: the nebula itself is quite small, requiring a substantial crop at a 264mm focal length. Furthermore, the acquisition took place around the summer solstice, from a relatively northern latitude, which means less than optimal observing conditions for this target. Yet, it's precisely these challenging conditions that make the pursuit of such targets so rewarding – it's part of the inherent game of astrophotography to strive for what is difficult when the skies grant us the opportunity.

The Equipment and Acquisition

Achieving this detailed capture required a robust setup and careful planning:

• Mount: Skywatcher 150i Wave mount
• Telescope: Askar SQA55 f/4.8
• Camera: ASI2600MC with gain 100 and offset 50, cooled to -5°C.
• Filter: Optolong L-Ultimate HaOIII filter
• Sub-Exposures: 203 subs of 300 seconds each, totaling an impressive 16 hours and 55 minutes of integration time.
• Observing Conditions: Captured under Bortle 8 skies, with a limiting magnitude of approximately 17.8.

The Processing Workflow

Turning raw data into a stunning image like this involves a meticulous post-processing workflow, primarily utilizing PixInsight and Lightroom:

1. Stacking: The individual sub-exposures were stacked using PixInsight's Weighted Batch Processing Platform (WBPP), with drizzle integration set to x2 for enhanced detail.
2. Initial Processing: This included an initial crop to frame the target, followed by Dynamic Background Extraction (DBE) to correct any gradients.
3. Detail Enhancement: BlurXterminator was used to sharpen the image and reduce noise, followed by Histogram Transformation to set black and white points and boost contrast.
4. Star Reduction: StarXterminator was employed to manage star sizes, allowing the nebula to truly pop. Further curve transformations and NoiseXterminator were applied for refined detail and noise reduction.
5. Final Touches: "Lightroom shenanigans" – a creative touch in Adobe Lightroom to bring out the final colors and impact of the image.

This image is a testament to the perseverance required in astrophotography, demonstrating that even with challenging skies and a difficult target, beautiful results can be achieved through dedication and skill.