The Night Sky - Episode 10
THE VEIL NEBULA COMPLEX
This is episode 10 in my series on our night sky.
The Veil Nebula Complex (Sh2-103), also known as the Cygnus Loop, is an intricate and enchanting cloud of ionized gas and dust. It is a nebula that spans a significant portion of the night sky and is located in the Cygnus constellation. This celestial masterpiece is the remnant of a massive star's cataclysmic death, a supernova that occurred thousands of years ago.
Let’s take a closer look.
An image of the Veil Nebula Complex (Sh2-103). A total of 15 hours of faint light from deep space were captured to create this image.
Image by Achint Thomas
The complex, approximately 2,600 light-years from Earth, stretches across an expanse of space that’s 120 light-years across. The sheer size of this nebula complex in the night sky is staggering, covering an area of about 3 degrees across the celestial sphere. To put it in perspective, that's roughly six times the diameter of the full moon. This vast expanse allows it to be easily observed with binoculars and telescopes, and it's a favourite target for astrophotographers seeking to capture its mesmerizing details.
The Sharpless Catalog
In the field of astronomy, Stewart Sharpless left an indelible mark by doing seminal work on the structure of the Milky Way galaxy. He also surveyed several H II regions (emission nebulae) in the night sky and listed them in the Sharpless Catalogue. The Sharpless catalogue serves as a guide to some of the most intriguing and visually stunning objects in the night sky, making it an invaluable resource for both amateur and professional astronomers. The Veil Nebula Complex is part of this catalogue and is designated as Sharpless 103 (Sh2-103).
Supernova Remnants: Echoes of Celestial Explosions
Supernova remnants, like the Veil Nebula Complex, are the relics of massive stars that met their explosive end. These cataclysmic events, in which a star dramatically collapses and then rebounds in a massive explosion, are integral to the universe's life cycle. The remnants testify to the unfathomable energy released during these cosmic outbursts. As the explosion tears the star apart, it propels its outer layers into space, creating shockwaves that collide with surrounding interstellar material. This collision creates the vibrant, glowing gases that we observe in regions like the Veil Nebula Complex.
The star that went supernova to create the Veil Nebula Complex is estimated to have been 20 times as massive as our sun and met its violent end between 10,000 and 20,000 years ago. At the time, the explosion would have been so powerful that the supernova would have been visible from Earth during the daytime. Over the millennia, the remnants of the explosion have evolved into a breathtaking display of filaments, arcs, and wisps that stretch across the cosmos, much like the tattered remnants of a once-majestic veil.
Supernova remnants also play a crucial role in enriching the cosmos with heavy elements such as iron, gold, and silver, which are necessary for forming planets and life as we know it. They are the cosmic forges where these elements are born, and their remnants continue to influence the regions around them, shaping the environment for new star formation.
As we gaze upon the Veil Nebula Complex, we are transported into the heart of a cosmic explosion, witnessing the birth of new stars and the dispersal of essential elements into the cosmos. It is a stunning example of the beauty found in the remnants of destruction, where the delicate interplay of forces and materials results in the old giving way to the new.
Update (Oct 28, 2023)
On Oct. 29, 2023, at 9:35 p.m. MDT, NASA will be flying a special "sounding rocket mission" to study this specific nebula. The mission, named INFUSE, will collect readings of the nebula in the far ultraviolet wavelengths to study how material from supernovae becomes part of planets and humans.
Locating the Veil Nebula Complex
The Veil Nebula Complex resides within the Cygnus constellation's boundaries, often affectionately referred to as the "Swan" due to its distinctive shape. Cygnus is sometimes called the backbone of the Milky Way galaxy. It is a prominent constellation in the summer night sky, and stargazers can easily spot its characteristic cross-like pattern.
Location of the Cygnus constellation in the Milky Way. The “Region of Interest” marks an area teeming with numerous nebulae including the Veil Nebula Complex.
Image by Achint Thomas
Cygnus is home to numerous nebula since it is a hydrogen-rich area of the galaxy, including the Gamma Cygni Nebula (IC 1318), the North America Nebula (NGC 7000), the Pelican Nebula (IC 5070), the Crescent Nebula (NGC 6888), and the Tulip Nebula (Sh2-101).
The Veil Nebula Complex is located beside the left wing of the swan.
Location of the Veil Nebula Complex in the Cygnus constellation.
Image by Achint Thomas
Components of the Veil Nebula Complex
The Veil Nebula Complex is vast. It is composed of many notable structures. Several interesting features are present in the immediate vicinity of the complex, including HII regions, objects from the NGC, IC, and LDN catalogues, and prominent stars in the Cygnus constellation.
Annotated image of the region around the Veil Nebula Complex
Image by Achint Thomas
The nebula complex itself has several prominent components, each with its unique characteristics.
The Western Veil: Filaments of Cosmic Fire
The Western Veil, also known as the Witches' Broom Nebula, is one of the most visually striking segments of the Veil Nebula Complex. It is a complex network of bright, intricate ionized gas filaments emitting a radiant glow. The filaments within this portion of the nebula complex are the remnants of the outer layers of the star that exploded in a supernova to create the complex. The Western Veil's intricate structure is evidence of the dynamic forces at play during the explosion, with shockwaves and stellar winds sculpting its delicate threads.
Western Veil Nebula
Image by Achint Thomas
The Eastern Veil: A Spectacular Curtain of Light
In contrast to the Western Veil, the Eastern Veil showcases a different aspect of the nebula complex's splendour. This portion of the complex is often called the Network Nebula due to its intricate, lace-like appearance. The delicate, filamentary structure of the Eastern Veil results from the interactions between the fast-moving shockwaves and the surrounding interstellar medium. Prominent in the Eastern Veil is 52 Cygni, a yellow-hued giant star that is easily visible to the naked eye from relatively dark locations.
Eastern Veil Nebula
Image by Achint Thomas
Pickering's Triangle: A Playful Melange of Colours
Pickering's Triangle is yet another intriguing component of the complex. Named after the American astronomer Edward Charles Pickering, this region is a striking triangular-shaped area of ionized gas. Its unique geometry results from the intricate interplay between shockwaves and the denser regions of the surrounding interstellar medium.
Pickering’s Triangle
Image by Achint Thomas
While each component of the Veil Nebula Complex is unique, what is common to all components is the contrasting complementary colours that render the nebula complex a captivating visual spectacle. The tendrils of gas that constitute the nebula complex are rich in ionized oxygen and hydrogen, lending the vivid blue-green and red colours which captivate observers.
Special Image Processing Techniques for Nebulae
Astrophotography is a blend of science and art, requiring a delicate balance of technical precision and artistic sensibility. When capturing an image of the Veil Nebula Complex or any other celestial object, several specialized image processing techniques are employed to produce a striking final image.
Most images of nebulae benefit from narrowband image processing methods like HOO Processing.
Read more about HOO processing in my episode on the Crescent Nebula.
Another technique is Star Removal, where the nebula is processed separately from the stars in the frame.
Processing astro images without first removing the stars results in the stars being overblown and dominating the frame. The details of the nebula are not easily visible, and accurate colour rendition is difficult.
Image by Achint Thomas
Specialized software first extracts only the stars from the original image to end up with a stars-only image and a star-less image. A commonly employed technique is to use morphological operations with image processing algorithms to detect the stars and create masks to exclude them from the image. This is usually a time-consuming and error-prone process.
In recent years, there have been remarkable advances in astrophotography driven by artificial intelligence. Neural networks, specifically convolutional neural networks (CNNs), have been harnessed to develop innovative solutions for star removal. AI-based tools can now intelligently identify and remove stars, making the process more efficient and user-friendly. These neural networks are trained on vast datasets of astronomical images, learning to distinguish between stars and other celestial objects.
Using the Star Removal technique to first extract stars from the image and processing the nebula and stars separately results in a better final image.
Image by Achint Thomas
The star removal step allows astrophotographers to enhance the details and colours of the nebula without overexposing the stars or introducing unwanted artifacts. It involves a meticulous process of layering and combining multiple exposures, each with a specific focus on either the nebula or the stars. The result is a striking image that reveals the nebula complex's intricate beauty while preserving the surrounding stars' brilliance, creating a visual masterpiece that bridges art and science.
The Veil Nebula Complex, with its intricate filaments, vibrant colours, and dynamic structure, is a testament to the grandeur and complexity of the cosmos. This captivating supernova remnant serves as a perpetual reminder of the incredible forces that shape our universe. It invites us to explore the universe's history and glimpse its future, reminding us of the eternal cycle of creation and destruction that governs the cosmos.
Check out some other nebulae I have captured.
Capture details
Camera: Astro-modified Canon 80D
Lens: Sigma 100-400mm f/5-6.3 DG OS HSM
Focal length: 250mm (equivalent to 400mm full-frame)
f-Ratio: 6.3
ISO: 800 and 3,200
Number of exposures: 179 total
- 179*300s with Optolong L-Enhance filter
Total integration time: ~15 hours over 4 sessions
Calibration frames: 30 darks, 30 flats, 30 bias for each session
Mount: SkyWatcher Star Adventurer
Guide camera: ZWO 120mm mini
Guide scope: ZWO Mini Guide scope
Capture control: ZWO ASIAir Pro
Dew control: CooWoo dew heater
Sky quality: Bortle 5
Moon phase: No visible moon
Processing: PixInsight, Photoshop