Image of the solar eclipse on April 8, 2024 featuring a sharpened HDR corona.

See https://astrob.in/wz0sot/F/ for my eclipse story...  Observing the silvery halo of the corona during totality was an astounding experience.  I don't recall seeing a lot of detailed structure, but then again I was pretty much awestruck the entire time is was visible.  I took a series of images over a range of exposures with the hopes of generating an HDR corona image.  I spent the past week or so reading up on corona HDR image processing and sharpening.  My data isn't the greatest in part due to the high clouds we observed the eclipse through, but in the end with this processing I was able to pull out some interesting details that at least on a large scale match up with other HDR sharpened corona images from the eclipse.

Imaged with a Astro-Tech AT60ED, 1.6x Antares Barlow, UVIR Cut Filter 2", and Nikon D5300 (astro modified). Imaging train was configured to give ~F/11 (FL=650mm).  Eight exposures ranging from 1/4000 second to 1/50 second at ISO-1600.

Processing steps:
(1) Initial processing of RAW image files in Pixinsight:  debayering, noiseXterminator, color calibration, automatic background extraction, and histogram transformation stretch.
(2-original) HDR and radial filter processing using Affinity Photo 2:  Loaded 8 images into a stack and generated a merged image using mean combination.  Applied radial blur filters using the method outlined in:  https://www.cloudynights.com/topic/919097-eclipse-hdr-stack-processing-tips-for-affinity-photo/.  I tried radial filter increments from 10  to 90 degrees and found that 10 and 20 looked best and higher values looking over processed.  Export exported the radially blurred HDR images.  Using Pixinsight generated luminosity images for further processing.
(2-alternate) HDR and radial filter processing using Affinity Photo 2:  Loaded 8 images into HDR merge and then tone mapped.  Applied radial blur filters using the method outlined in:  https://www.cloudynights.com/topic/919097-eclipse-hdr-stack-processing-tips-for-affinity-photo/. Radial filter increments from 5  to 20 degrees were applied with 5 and 10 degree versions combined for the final image.  Export exported the radially blurred HDR images.  Using Pixinsight generated luminosity images for further processing.
(3)  Applied additional sharpening to the luminosity images using NAFE solar image processing software.  Reference:  http://www.zam.fme.vutbr.cz/~druck/Nafe/Index.htm
(4)  Additional processing on NAFE sharpened luminosity images in Pixinsight:  Generated master luminocity image by combining multple NAFE sharpened images, applying masked curves adjustments (central solar disk masked), applying noiseXterminator, and HDR multiscale transformation.
(5) Generated final color image using LRGB combination process in Pixinsight:  Luminosity from NAFE sharped master and RGB from base image.  Additional application of HDR multiscale transformation.

Original:  Final sharpened HDR corona image (using step 2 - original)

Rev B:  Base image generated from the mean of 8 sub images using Affinity Photo 2

Rev C: Radially blurred base image (10 degrees)

Rev D:  Master luminosity (Radially blurred image sharpened in NAFE and Pixinsight)

Rev E:  Master luminosity, inverted

Rev F:  Alternate Final HDR Tone Mapped image sharpened using radial blur and NAFE (using step 2-alternate)

Rev G:  HDR Tone Mapped Image with radial blur applied at 5 and 10 degrees