Deconvolution is a fantastic tool for high resolution setups. I use it for sharpening of the stars and bright details in my images. Globular clusters are an excellent candidate for this process. The animation below shows subtle changes in clarity of the core and larger stars are reduced to a sharper, more focused point of light as the effect of atmospheric blurring is undone.
I intentionally chose to keep the brightness of the core on the low side to better show the star color all the way to the center, as high brightness washes out color.
Retrospective: small Apo versus large NewtonianBelow is an animated image comparison with results from my 80 mm triplet Apo refractor, captured in May 2019. Chromatic aberration is controlled much better in the image from the Newton, especially on bright and overexposed stars (see the revisions for full image and quality). It's just a lot easier to get good star color on the Newt. Dimmer stars are also slightly sharper in the Newt image, which is expected due to the larger aperture. The older image was shot with ZWO LRGB filters, and the new image with Astrodon LRGB so that will likely account for some of the difference in color. That said, the image from the much smaller telescope holds up surprisingly well!!
Technical: I drizzled the refractor data and tried to process it similar to the data from my Newt. Both images were color balanced with PixInsight's PhotometricColorCalibration module. All data was manually deconvolved with the regularized Richardson-Lucy algorithm, and stretched with a Log function. Before deconvolution, there was a lot more star bloat in the refractor data. Native and deconvolved refractor data was mixed to better match the star profile of the Newton. Green and Purple color casts were removed from the refractor data with application of 80% SCNR on normal and inverted colors.
2019 processing :
M13 - Hercules Globular Cluster 
Comments