The Iris Nebula is a bright, large reflection nebula located approximately 1,300 light-years away in the constellation Cepheus. With an apparent magnitude of 6.8, the nebula is visible in backyard telescopes. It is one of the most popular astrophotography targets in the northern sky.
The nebula has the designation NGC 7023 in the New General Catalogue and Caldwell 4 in the Caldwell catalogue of deep sky objects visible to amateur astronomers. The New General Catalogue designation refers to the open star cluster NGC 7023, which is associated with the nebula, while the nebula itself is designated LBN 487 or VdB 139. The star cluster is visible as the “top hat” above the center of the nebula.
Named for its resemblance to the iris flower, the Iris Nebula has a diameter of 6 light-years and occupies an area of 18 by 18 arcminutes of the apparent sky. It appears near Alfirk (Beta Cephei), one of the bright stars that outline the constellation figure of Cepheus. The fainter variable red giant T Cephei also appears near the nebula.
Image Session Details
-Location: 50.23°N, 8.46°E
-Target: NGC 7023 – Iris Nebula
-Integration: 85 × 180s = 4h 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: Waning Crescent (~17%)
-Filter: None (stock DSLR)
-Date: 19 August 2025
-Object Type: Reflection Nebula
-Constellation: Cepheus
-Apparent Size: ~18′ × 18′
-Distance: ~1,300 light years
General Properties
Coordinates: 21h 01m 36s, +68° 10′ 00″ (J2000)
Apparent Magnitude: 6.8
Angular Size: ~18′ × 18′
Distance: ~430 pc (1,400 ly)
Constellation: Cepheus
Discovery: Discovered by Sir William Herschel in 1794
Scientific Databases
[ POSITION ]
RA: 315.403700°
Dec: +68.163300°
Parallax: 2.905 mas
Proper motion: pmRA=7.82 mas/yr, pmDEC=-1.09 mas/yr
[ PHOTOMETRY ]
IRAS 12 µm: 26.70 Jy
IRAS 25 µm: 76.80 Jy
IRAS 60 µm: 638.00 Jy
IRAS 100 µm: 1100.00 Jy
1.4 GHz flux: 0.02 Jy
[ DISTANCE ]
340.67 pc (1.11 kly, Gaia proxy (median bright-star parallax))
[ ALIASES ]
IRIS Nebula, IRAS 20599+6755, IRAS 21009+6758, IRAS F20599+6755, IRAS F21009+6758, LBN 104.08+14.21, LBN 487, NGC 7023
-NED
Observation Notes
-Photographic Magnitude: 7.1
