SH2-142 (Wizard Nebula)

SH2-142 (also known as Wizard Nebula) is an emission nebula in constellation Cepheus with an apparent diameter of about 50' (arcminutes). The nebula is ionized by the young star cluster NGC 7380, in particular by DH Cephei, a binary system consisting in two O-type stars. DH Cephei lies at a distance of about 9600 ly from Earth (Gaia DR3 data).

Click on the images for a full scale version.

SH2-142 (Wizard Nebula) in false colors (SHO)
This image is a false color composite where [SII] is mapped to red, H-alpha is mapped to green and [OIII] is mapped to blue. Stars are partially subtracted using continuum images.

DH Cephei, the main ionizing source, is the brighter star in the center of the image.

SH2-142 (Wizard Nebula) in false colors (OHS)
Same view as above, but [SII] and [OIII] are swapped in order to improve the visibility of the oxygen structures (reddish).

Image data

FOV: 0.67° × 0.51°
Date: 2018-2021
Location: Pulsnitz, Germany
Instrument: 400mm Newton at f=1520mm
Camera Sensor: Panasonic MN34230
Orientation: North is up (approximately)
Scale: 0.8 arcsec/pixel (at full resolution)
Total exposure times:
H-alpha (3nm): 8.3 h
[OIII] (3nm): 10.4 h
[SII] (3nm): 14.1 h
NIR: 0.8 h
Blue: 0.4 h

Image processing

All image processing steps are deterministic, i.e. there was no manual retouching or any other kind of non-reproducible adjustment. The software which was used can be downloaded here.

Image processing steps where:

  1. Bias correction, photon counting
  2. Dark current subtraction, flatfield correction, noise estimation
  3. Alignment and brightness calibration using stars from reference image
  4. Stacking with masking unlikely values and background correction
  5. Extracting stars from the emission line images using information from continuum images
  6. Denoising and deconvolution both components (stars and residual)
  7. RGB-composition
  8. Dynamic range compression using non-linear high-pass filter
  9. Tonal curve correction

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