M42 - Orion's Nebula

While shooting one second images off my balcony was a good start, I was ready to head to dark skies and get my polar alignment working.

This was my first attempt and I am really happy with it!

I really did struggle with polar alignment.  Finding Polaris in the sky was easy.  Finding it through the polar scope, well, I don't think I did.  After about an hour of trying, I sort of just eyeballed it in the general direction of north.  It was just enough, though, to take 20sec images at 800mm!  I was setting up and shooting from about 7:00pm to 9:30pm.  So how come I only managed 11min of exposures?  Orion was pretty high in the sky by the time I got my act together.  Shooting vertical was awkward and the camera kept sagging on the ball head due to the weight of it and so M42 kept disappearing out of frame.  I am pretty sure I also need to invest in a second counter weight for the SkyGuider.


  • 800mm, f11, ISO4000, 34x20sec (11min)
  • 24xBias, 28xDark, 22xFlat

Orion's Nebula and the Running Man Nebula


I very quickly eliminated DeepSkyStacker for calibrating and stacking my images.  I tried all sorts of permutations and image formats (jpg, dng, tiff) but DSS just doesn't have the power to deal will the Sony A7RII images.  So by eliminating DSS, it meant that StarTools was also off the table as that program does not do stacking.  This left PixInsight.  Several hours of YouTubing later, I came up with a very nicely processed image.  I would recommend Richard Bloch.  PixInsight is pretty complicated but I think he has the right approach and that you can get better results sooner by actually doing things manually rather than using the short cuts and batch processing options.  A bit like learning how to do long division before you start using a calculator. :) 

That said, I manually calibrated and stacked the images in PixInsight and processed the image.  This took me about 9 hours.

The basic order of processing steps are:

  1. Crop
  2. Automatic background extractor
  3. Colour calilbration
  4. Manual histogram stretching
  5. Noise reduction
  6. Sharpen
  7. Contrast
  8. Saturation

I later researched that David Aldrich recommends doing noise reduction after colour calibration not after histogram stretching.  He has a more in depth method for noise reduction which I might try next time.

I took the final tiff from PixInsight and did some more tweaking in Lightroom and GoogleNix.  I did some more localised noise reduction and dodging and burning around M42.  The start points effects was done in Topaz Star plugin.  I really liked to be able to see how the stars are different colours. Red, orange, green, blue and white.

Next Target?  Pleiades M45 and the Horse Head and Flame nebulae.