Horsehead Nebula

The image shows:

the (upside down) Horsehead Nebula, Barnard 33;
the red emission nebula IC434 (mag 7.3);
the emission nebula NGC 2024, Flame Nebula (mag 10);
the very bright star Alnitak (mag +1.7 and +3.7 double);
the smaller nebula NGC 2023 (mag 10); and
an Earth orbiting satellite trail.

The Horsehead is a challenging object for visual observers to detect but using live stacking photography it is a sheer joy to behold, as it it slowly reveals, on site, the red nebulosity and the dark outline of the Horsehead itself.

Object Details:

Barnard 33
Constellation: Orion.
Visual magnitude: na
Apparent size: 6′ x 4′
Distance: 1,600 light years.
Altitude: 47° above NE horizon.


Exposure: 61 x 60 sec = 61 min. Live stacked.
Gain 337
Date: 2018-12-08 commencing approx 11.15 pm
Location: The Oaks, NSW.


Sky: semi-dark rural.
Cloud: clear.
Moon: no.


Image acquisition software: SharpCap.
Image post-processing:  GIMP.
Cropping: no.

Geek Log

[ZWO ASI071MC Pro]
Output Format=PNG files (*.png)
Capture Area=4944×3284
Colour Space=RGB24
Hardware Binning=Off
Turbo USB=80(Auto)
Frame Rate Limit=Maximum
Timestamp Frames=Off
White Bal (B)=61(Auto)
White Bal (R)=59(Auto)
Cooler Power=100
Target Temperature=-15
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Anti Dew Heater=On
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=None
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.5
#White Point
Display White Point=1

Imaging telescope: Skywatcher Esprit 120ED Super APO triplet refractor.
Focal length: 840 mm, focal ratio: f/7.
Imaging camera: ZWO ASI 071 MC Pro
Guiding: off (guide camera malfunction).
Telescope mount: SkyWatcher EQ6-R.
Polar aligning method: QHYCCD PoleMaster.
Polar alignment error: 1′ 51″.
Field flattener: yes; filter: no.
My gear.

Observing Notes:

This was another frustrating night because again the mount would not carry out a successful three star alignment. It will shortly be on it’s way back to the manufacturer for replacement under warranty.

I was determined not to let the problems beat me and I managed to image not only the Horsehead but also Comet 46P Wirtanen.

Despite my alignment woes, I was able to manually manoevre the telescope to find the Horsehead. Regardless of its dark nature, it was surprisingly easy to find, being very close to the bright star Alnitak in Orion’s Belt.


The Orion Nebula : December 2018

My Nebula Portfolio


Since posting this I have learned that to avoid inclusion of satellite trails I need to select sigma-clipping alignment in the live stacking options. Too late now!

Image © R.Powell




  1. Hi Richard. That’s an orbiting satellite gate-crashing my party.
    It’s increasingly common these days but I choose to live stack on site – and a consequence of that is accepting the final product, warts and all.
    Thanks for your comment.


    1. Hi Will.
      This object is probably the only one where flipping 180 degrees would be mandatory.
      If I had done so, the image may have had more visual impact – but I would not have had so many comments on the various forums,.., LOL…
      Happy New Year!

      Liked by 1 person

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