Pickering’s Triangle

This is my recent photograph of Pickering’s Triangle, showing the remnant entrails of an exploding star.  It is part of a much bigger deep space object called the Veil Nebula. Between about 10,000 and 20,000 years ago, a massive star exploded in a supernova leaving behind an expanding shell of hot gas which is now impacting and exciting other nearby gases to give it its colours. Blue is oxygen and red is hydrogen. Pickering’s Triangle is part of the northern edge of that shell.

Hera 0.4 processing

I continue to develop my astrophotograph processing software, Hera, now in version 0.4. Here is a two-minute demonstration of processing this image in Hera:

Processing in Hera version 0.4

You will see in the video that I made use of one of my latest processing tools, nox (color), to separate the stars from the rest of the image. This allowed me to separately enhance the nebula and reduce the stars, before recombining the nebula and stars at the end. Nox is turning out to be extremely powerful and useful. I love the starless images it produces, like the one below (during an early stage of processing):

AI-driven nox star removal

One of my other favourite processing tools is CLAHE (contrast-limited adaptive histogram equalization), which produces an effect that is very similar to Clarity in Adobe’s Camera Raw Filter or Local Contrast Enhancement in Astronomy Tools. The image below shows Pickering’s Triangle before and after histogram equalization.

Image details


  • 109× 150-s light frames (Gain 900)
  • 4 h 32 min 30 s total integrated exposure time
  • Full use of calibration frames (darks, flats, dark flats)


  • Explore Scientific ED 102 mm Apo f/7 refractor
  • Revelation Adjustable Field Flattener
  • Sky-Watcher EQ6-R PRO SynScan GOTO equatorial mount
  • Altair Hypercam 294C PRO colour fan-cooled camera
  • Altair quad-band one-shot colour (OSC) 2″ filter
  • Pegasus FocusCube v2
  • Altair 60mm guide scope
  • Altair GPCAM2 AR0130 mono guide camera
  • Hystou Rugged Fanless Mini PC i5 7260U


  • SharpCap 4.0
  • PHD2
  • DeepSkyStacker
  • Hera 0.4
  • Topaz DeNoise AI Low Light for sharpening

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