SH2-112

SH2-112 is an emission nebula in constellation Cygnus with an apparent diameter of about 18' (arcminutes). The nebula is ionized by the O-type star BD +45 3216 (the bright star near the center of the nebula) which lies at a heliocentric distance of about 8000 light-years.

Click on the images for a full scale version.

SH2-112 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.
SH2-112 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° × 0.5°
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): 10.6 h
[SII] (3nm): 14.2 h
NIR: 1.1 h
Blue: 0.5 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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