Key Scientific Data
Object type: Emission nebula – H II region
Constellation: Cassiopeia
Other designations: NGC 7635, Sharpless 162, Caldwell 11, Bubble Nebula
Distance from Earth: approximately 7,100 light-years Diameter: approximately 7 light-years (central bubble)
Apparent size: approximately 15 × 8 arcminutes (surrounding nebula)
Apparent magnitude:approximately 10
Central star: SAO 20575 (BD+60°2522), massive O-type star
Stellar mass: approximately 40–45 solar masses
Estimated age: approximately 4 million years (central star)
Right Ascension: 23h 20m 48s
Declination:+61° 12′ 06″
Discovered by: William Herschel, 1787
Notable feature: Stellar-wind bubble expanding into surrounding interstellar gas
Light-travel time: approximately 7,100 years
Description
NGC 7635, known as the Bubble Nebula, is an emission nebula located in the constellation Cassiopeia.
Its distinctive spherical shell is created by powerful stellar winds from the massive, hot star SAO 20575, which push surrounding gas outward at high velocities.
The bubble's asymmetric structure results from interactions with the dense molecular clouds surrounding it.
This image combines Hα and OIII narrowband data with RGB stars, revealing the delicate shell, surrounding hydrogen emission and intricate dark dust structures.
Looking Back in Time
The light captured from NGC 7635 began its journey approximately 7,100 years ago, around 5100 BCE.
At that time, humanity was entering the Neolithic period in many regions, with agriculture and permanent settlements spreading across Europe and the Near East.
In Mesopotamia, early farming communities were developing increasingly complex societies, while in Europe the first agricultural cultures were establishing themselves.
The Egyptian pyramids and the earliest cities were still thousands of years away.
Image Data
Total integration: 22h 19m
Integration by filter:
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R: 1h 20m (80 × 60s)
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G: 59m (59 × 60s)
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B: 1h (60 × 60s)
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Hα: 9h 20m (56 × 600s)
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OIII: 9h 40m (58 × 600s)
Equipment:
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Telescope: Artesky ARTEC 250 Pro
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Camera: Player One Poseidon-M Pro
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Mount: 10Micron GM2000 HPS II
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Filters: Antlia 3nm H-alpha, Oxygen III and Sulfur II Pro Highspeed 2"; Antlia V-Pro RGB 2"
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Accessories: Pegasus Astro Prodigy Microfocuser, Player One Phoenix Wheel 7×2", WandererAstro WandererCover V4-EC
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Software: PixInsight, Adobe Photoshop, N.I.N.A.
Location: Innumerabili Mondi Observatory, Arpino, Italy Acquisition: October 2026 Processing: Hα + OIII + RGB stars
AstroBin: https://app.astrobin.com/i/wg34f5