Sh2-129 OU4: Unveiling the Flying Bat and Squid Nebulae in Stunning Detail

Prepare to be captivated by the ethereal beauty of Sh2-129 OU4, affectionately nicknamed the Flying Bat and Squid Nebulae. This incredible image showcases the intricate structures and vibrant colors of these celestial wonders, brought to life through dedicated astrophotography.

The Imaging Process: A Symphony of Data and Dedication

The creation of this stunning image involved a substantial investment of time and expertise. The acquisition phase alone spanned an impressive 25 hours and 8 minutes, utilizing a total of 277 exposures, each lasting 240 seconds. The clear night skies allowed for an NELM (Naked Eye Limiting Magnitude) of Mag 4, with 31 Cygni being visible, indicating excellent observing conditions.

Specifically, the Oiii (Oxygen III) data was extracted from the full 25 hours of acquisition, while the Ha (Hydrogen Alpha) data was culled from 16 hours and 56 minutes. These two crucial datasets were then masterfully combined using the Perfect Palette Picker within the Seti Astro Suite, resulting in the striking HOO (Hydrogen Alpha, Oxygen III, Oxygen III) color combination.

The Gear Behind the Image:

To achieve such remarkable detail, a specialized setup was employed:

• Imaging Telescope: Askar V with an 80mm reducer (resulting in a focal length of 384mm).
• Camera: Ogma AP26CC (IMX571 sensor).
• Filters: Antlia Triband filters were used to capture the specific light emissions.
• Guiding: Skywatcher Evoguide 50DX paired with a Player One Uranus C camera and a UV-IR Cut filter for precise guiding.
• Mount: Skywatcher Wave 100i.
• Software: A robust suite of software powered the acquisition and guiding, including Green Swamp Server, ASCOM, NINA for acquisition, and PHD2 for guiding.

A Deep Dive into the Processing Pipeline:

The journey from raw data to the final polished image involved a meticulous processing workflow:

1. Image Calibration: 15 Darks and 50 Dark Flats (Bias) were used alongside 50 Flats for image calibration.
2. Initial Alignment & Enhancement: RGB Alignment was performed, followed by Autostretch and Astrometry.
3. Background Management: Background Extraction was crucial, employing RBF (Residual Background Flattening) with specific smoothing and sampling settings, along with a Polynomial approach for background removal.
4. Color Calibration: Photometric Color Calibration using GAIA data ensured accurate color representation.
5. Noise Reduction: Green Noise Removal was carried out in Siril.
6. Star Removal: Starnet was used to create a starless version of the image.
7. Data Extraction & Combination: The DxBextract script in Siril was instrumental in isolating Ha and Oiii data. These were then combined in the Perfect Palette Picker (Seti Astro Suite) to generate the HOO composite.
8. AI Denoising: The starless image was processed with AI Denoise in ON1, saved as a PNG, and then converted back to FIT format in Siril.
9. Star Recomposition: The starless image was recomposed with an unstretched starmask to reintroduce stars naturally.
10. Final Touches: The image was resized in ON1 and saved as a PNG.

This image is a testament to the dedication and skill involved in modern astrophotography, offering a unique window into the vastness and beauty of our universe.