Astronomical Image Processing

I have processed astronomical images since 2003, learning along the way through self-learning and workshops, and improving my image acquisition methodologies and equipment.


Deep sky objects – I normally take light, dark and flat frames using either a dSLR or cooled CCD astronomical imager. I rarely take bias frames, since the contribute minimal improvements to resultant images. Original images are exposed to ensure the histogram indicates sufficient data to successfully support stacking of multiple images.  If using a cooled CCD imager, I make use of the Pelletier cooler to reduce the sensor temperature by at least 20°C, which improves the noise levels immensely.

Solar System objects – I use video frames, single shot exposures, and sequential exposures to image the Sun, Moon, planets and comets.

Setup of my imaging hardware varies widely, so I won’t describe that here.


  • ImagesPlus is my main image processing software to process the raw files through to a useable resultant image. Mike Unsold created this software about the same time I started imaging the night sky. ImagesPlus is optimized to work with large datasets, large format files, and uses hard drive storage efficiently. I have been very pleased with the advances in the software, so I have supported Mike in his efforts by purchasing updates as he released them. He has never released a buggy version of his software – a testament to his conservative approach to software development. ImagesPlus supports both astronomical and consumer dSLR camera raw formats directly, but works in the FITS format internally, and produces FITS as a resultant processed image. I have tried other astronomical image processing software along the way, but I always consider ImagesPlus to be the trusted tool to process my night sky images.
  • Lightroom is the software I use to manage my image datasets during the last few years. Adobe recently moved away from perpetual licensing to a subscription licensing model, which I do not like, however Lightroom Classic is my go-to software to manage my extensive astronomical image datasets (up to 2019). I also use Lightroom Develop to finish the resultant images produced by ImagesPlus (in TIFF format), since Adobe has integrated many of the more useful image processing capabilities of Photoshop into Lightroom.
  • ACDSee Photo Studio is the software I am transitioning to (in 2019) to manage my image datasets, since it has all the functionality of Lightroom Classic, but has perpetual licensing instead of a subscription. It is much faster to use than Lightroom.
  • Other software – The above two packages are my main tools to produce final results, however I make use of other software on occasion to manage noise, file conversion and development, image acquisition using a computer/USB connection, planning imaging sessions, and more.

Processing logs – I keep notes of everything I do to produce my final results, so I can learn from my mistakes, document new approaches that are successful, and simply to refresh my memory when I haven’t processed a particular type of image for awhile.