NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region emission nebula in the constellation Cassiopeia. It lies close to the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575. The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in November 1787 by William Herschel
Image Session Details
-Location: 50.23°N, 8.46°E
-Target: Messier 52 and Bubble Nebula
-Integration: 130 × 90s = 3h 15m
-Camera: Nikon D3500 (APS-C DSLR) – ISO 400
-Telescope: Askar 103 APO + 0.8× reducer (576 mm)
-Mount: Bresser Exos-2 + OnStep
-Control: ASIAIR Mini
-Guiding: SVBONY SV165 + ASI120MM Mini
-Sky Quality: Bortle 4, SQM ~20.8
-Moon Phase: Waxing Gibbous (~61%)
-Filter: None (stock DSLR)
-Date: 01Octomber 2025
-Object Type: Globular Cluster + Planetary Nebula
-Constellation: Cassiopeia
-Apparent Size: ~15′ × 8′
-Distance: ~7,100–7,500 ly (≈2.2–2.3 kpc)
General Properties
Coordinates: RA 23h 20m 48s, Dec +61° 12′ 06″
Apparent Magnitude: ~10
Angular Size: ~15′ × 8′
Distance: ~7,100–7,500 ly (≈2.2–2.3 kpc)
Constellation: Cassiopeia
Discovery: William Herschel, 1787
Scientific Databases
[ POSITION ]
RA: 350.201200°
Dec: +61.201700°
[ PHOTOMETRY ]
IRAS 12 µm: 28.50 Jy
IRAS 25 µm: 182.00 Jy
IRAS 60 µm: 433.00 Jy
IRAS 100 µm: 313.00 Jy
1.4 GHz flux: 0.59 Jy
[ DISTANCE ]
388.73 pc (1.27 kly, Gaia proxy hot-star parallax)
~2.2–2.3 kpc (7.1–7.5 kly, nebula literature consensus)
[ PROVENANCE ]
Gaia DR3: source_id 2014149588055625984, G=6.91, BP−RP=0.05, π=2.572±0.025 mas
[ ALIASES ]
Bubble Nebula, LBN 548, NGC 7635, NGC7635, SH 2-162
-NED
Observation Notes
-Photographic Magnitude: 9.0
