Scroll Down

Horsehead and Flame Nebulae, DSLRa

The dark space horse (IC 434) and the star-forming flame (NGC 2024) in the Orion Molecular Cloud Complex, home to protoplanets and young and bright stars 1,400 light years away.

Processing Details

PixInsight

Dynamic Crop on the master calibrated and registered (star-aligned) light frame.

Background Noise Reduction with Automatic Background Extraction.

Auto-stretch with STF (ScreenTransferFunction) with linked RGB channels.

Noise reduction was performed with MultiscaleLinearTransform. 4 layers with the following settings (R as default):

  • Layer 1: Threshold 1.000, Amount 0.50, Iterations: 1

  • Layer 2: Threshold 1.000, Amount 0.50, Iterations: 1

  • Layer 3: Threshold 1.000, Amount 0.50, Iterations: 1

  • Layer 4: Threshold 1.000, Amount 0.50, Iterations: 1

Further noise reduction was applied with ACDNR and StdDev of 0.6 and Amount 0.50.

Star Reduction was applied with StarMask at 0.04000 Noise threshold, Scale 6 and Structure Growth as 0, 1 and 2 (Large-scale, Small-scale and Compensation).

Curves Transformations were applied to boost RGB/K and Saturation.

Photoshop

Selective Sharpening with High Pass Filter (radius 1.6).

Tech Card

Dates / Locations

10th November 2018, Exmoor, GMT+0, United Kingdom, TEMP: 8C, HUM: 96%, Bortle Class 3 ~SGM: 21.75 mag./arc sec2

14th, 16th, 28th & 30th January 2019, Bedworth, GMT+0, United Kingdom, Bortle Class 5 ~SGM: 19.57 mag./arc sec2

Equipment

Camera: Nikon D810A

Imaging Telescope: Takahashi FS-60CB

Correcting Lens: Takahashi Reducer 0.72x (composite focal length at 264mm and focal ratio at f/4.9)

Mount: iOptron CEM25EC

Image Quality

14 bit RAW (NEF)

Exposure time per image / number of composities and sensitivity

ISO 400 12 x 120" subs

ISO 400 77 x 180" subs

ISO 40, 5 x 240" subs

ISO 1600, 10 x 60" subs

ISO 1600, 8 x 180" subs (Bortle 5)

ISO 3200, 1 x 180" sub (Bortle 5)

Total Integration Time

5hrs 42mins

Calibration Frames

23 Darks, 23 Bias, 25 Flats

Software

PixInsight 1.8 Core

Photoshop