I set out to investigate how the colour density of images of star clusters changes with exposure duration, and M28 was very conveniently located at zenith at the time.
It also gave me an opportunity to add another Messier object to my image collection.
I captured subs at various exposures, just to see what changes there might be, not really expecting to produce a publishable image.
I was astonished at the depth and complexity of this target. The central cluster itself is stunning, and the extent and richness of the surrounding star field is simply breathtaking.
I was tempted at first to publish this image tightly cropped around the central cluster, but felt that this would separate the cluster from its context, so the image you see here is full frame and uncropped.
First I integrated groups of subs according to exposure duration, then integrated the master images from each set to produce a Full Master. I've applied almost no post-processing - just the usual adjustment curves, a small amount of noise reduction and that's about all.
I'm particularly pleased at the roundness of stars across the field, and the rich variation in star colours from deep blue to rich red.
I published this image at full resolution, in the hope that viewers will be tempted to '
zoom in' for a closer look
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