NGC 7023 - Iris Nebula
NGC 7023 is the designation of an open star cluster which is
embedded in a reflection nebula located in the west central section of the
constellation Cepheus. The nebula is known as "Iris Nebula" and is catalogued as
LBN 487 and as number 4 in the Caldwell catalogue. Its dust particles reflect
the light of the 7.1 mag star V 280 Cep. The distance to the nebula measures
about 1300 light years and the diameter about 6 light years.
The Iris Nebula shines at an apparent magnitude of 6.8 and is theoretically
bright enough to be visible with binoculars, but its large apparent size (18 arc
minutes) and diffuse nature makes this a hard task.
NGC 7023 was discovered by Sir William Herschel in 1794.
NGC 7023 - Iris Nebula and Surrounding
Area, telelens photograph.
- Instrument: 8" f/5 Newtonian
- F/stop: 4.75
- Exposure: 10 x 10 min
- Camera: ZWO ASI294MC Pro
- Offset/Gain/Temp: 30 / 0 / -24°C
- Date: September 10, 2018
- Exposure start: 02:51 MESZ
- Location: Wallackhaus, Carinthia
- Conditions: Visual limiting magnitude 6.3 mag, SQM-L sky brightness 21.4 mag/arcsec2, seeing 2.7" FWHM, temperature 1°C, no wind, no dew
- Autoguider: Lacerta MGEN
- Enhancement: Basic data reduction, registration and combination, background flattening, color calibration, noise reduction, deconvolution, non-linearization, local contract enhancement, star size reduction
- Notes: Photo taken during my stay at the
Großglockner-Hochalpenstraße in September 2018. My third try
with the Alpha Tauri 2000/1000 Newtonian and the ZWO ASI camera. Deconvolution
helped to decrease star sizes and improve the overall detail. Morning twilight
ended this exposure series.