IC 434 - Horsehead Nebula

The Horsehead Nebula (also known as Barnard 33) is a small dark nebula in the constellation Orion. The nebula is located just to the south of Alnitak, the easternmost star of Orion’s Belt, and is part of the much larger Orion Molecular Cloud Complex. It appears within the southern region of the dense dust cloud known as Lynds 1630, along the edge of the much larger, active star-forming H II region called IC 434.

(Source: Wikipedia)

Exposure data

Total integration: 15 hours 51 minutes

Instrument and equipment

• Sigma 150-600mm at f/7.1
• Skywatcher H-EQ5
• Canon EOS 1300Da
• Lacerta M-Gen Autoguider
• Astronomik Hα, OIII, SII filters
• TS-Optics 60mm Guide tube

Location

• Balcony observatory, Germany, BW
• Bortle 4

Used software

• APT + Stellarium for camera control
• EQMod for telescope control
• PixInsight for image processing
• Photoshop for final touch

PixInsight processing workflow:

Filter images:

• Calibration (Flats+Darks+Bias), Weighting (SS), Integration for each wavelength
• DrizzleIntegration (2x)
• DBE+ABE for HA, OIII, SII masters
• Synthetic Flat by MMT (only Layer 8 + R) from OIII for lense flare correction on OIII
  • CloneStamp for big star removal before MMT
  • CloneStamp for cleanup after MMT
  • Convolution for softening synthetic Flat
  • Divided from OIII via ImageCalibration
• TGVDenoise
• MMT
• SII+OIII LinearFit against Ha
• PixelMath for RGB (R=HA, G=SII, B=OIII)

RGB image:

• RGBWorkingSpace (Same Weight)
• SCNR (Green, 0.25)
• BackgroundNeutralization
• ColorCalibration
• MMT
• TGVDenoise
• Deconvolution
• MaskedStretch

RGB L:

• L Extraction from RGB
• MMT
• CloneStamp (fixing few black pixels)
• LHE (masked, only bright areas)

Final image:

• LRGBCombination of RGB and RGB_L with CNR and saturation boost
• CurvesTransformation for final color balance
• ATrousWaveletTransform for noise reduction
• UnsharpMask
• Convolution (with bright star mask)