M92 and Quasars
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June 15, 2026
Globular cluster Messier 92 (M92) lies in Hercules, not far from M13, which usually gets more attention from both visual observers and imagers. M92 is one of my favourite telescope targets, especially in my 20″ reflector. It lies about 26,700 light years away from us, and appears a little less than half the width of the full Moon. Its mass is about 200,000 times that of the Sun, and its age is estimated at 14 billion years.
On close inspection, there are a few obviously fuzzy ‘stars’ in this image. They are galaxies each of which is made of billions of stars. They’re marked in yellow in the annotated image. Although they are far away – on the scale of tens of millions of light years, that is nearby when you are talking about the scale of the universe. Check out the hundreds of quasars (‘quasi-stellar radio sources’) marked with white crosshairs. Quasars are extremely bright galaxies which are visible even though they lie up to 10 billion light years away. Zoom in to see their photons captured by my Player One camera and Sky-Watcher Esprit 120 telescope after billions of years of travel! I never cease to be amazed at what I can capture from my back yard.
I shoot M92 every few years with a variety of equipment, most recently in 2024 with my C14 and in 2021 with 6″and a 4″ refractors.
Tekkies:
Acquisition, focusing, and control of Sky-Watcher Wave 150i mount and other equipment with N.I.N.A. and Green Swamp Server. Primalucelab 3″ ESATTO focuser, ARCO rotator, GIOTTO flat panel and ALTO cover motor. Equipment control with Primalucelab EAGLE 6 Pro computer. All pre-processing and processing in PixInsight. Acquired from my SkyShed in Guelph. Acquired under above average transparency and seeing and moderate moonlight from May 27-June 4, 2026.
Sky-Watcher Esprit 120, Player One Poseidon-C Pro camera, Optolong L-Quad Enhance filter.
145 x 5m = 12hr 05m
17 x 2m = 0hr 34m
23 x 1m = 0hr 23m
Total = 13hr 02m
Preprocessing: The WeightedBatchPreProcessing script was used to perform calibration, cosmetic correction, debayering, weighting, registration, and Drizzle integration.
Gradient Removal: DynamicBackgroundExtraction was applied to remove gradients and most of the colour imbalance.
Colour Calibration: BlurXterminator was applied to the RGB master with Correct Only selected, followed by SpectrophotometricColorCalibration.
Deconvolution: BlurXterminator was applied to the RGB master with Automatic psf , star sharpening set to 0.5, and non-stellar set to 0.9.
Stretching: MultiscaleAdaptive Stretch was applied to make a pleasing image with background approximately 0.1.
Nonlinear Processing
Star Removal: StarXterminator was used to remove the stars from the master using default settings, except Large Overlap was selected. The stars-only image was retained and processed as described below.
Nonlinear Noise Reduction: NoiseXterminator was applied to the starless image with Amount=0.9 and Iterations = 4
Re-stretch: HistogramTransformation was used to boost contrast in the starless image by raising the dark point about halfway to the toe of the histogram and slightly decreasing the mid-point slider.
Contrast, Brightness and Colour: Brightness, contrast, hue, and saturation were adjusted in several iterations using CurvesTransformation.
Stars-only steps: The CIE L* channel (i.e. the lightness channel) was extracted from the stars-only image using ChannelExtraction and was then applied to the star image as a mask. CurvesTransformation’s Saturation slider was used to boost colour in the stars.
Star Restoration: The PixelMath expression combine(starless, stars, op_screen()) was used to combine the starless starless image with the stars-only image.
Final Steps: Background, cluster, and star brightness, contrast, and saturation were adjusted in several iterations using CurvesTransformation with masks as required. ICCProfileTransformation (sRGB IEC61966-2.1; Relative Colorimetric with black point compensation) was applied prior to saving as a jpg. The finder chart was made using the FindingChart process. The annotated image was made with the AnnotateImage script.
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