Visual Corona 4 - 2017 Total Solar Eclipse
The solar corona is only visible for a few brief minutes during a total eclipse of the Sun. Because the corona encompasses an enormous range of brightness (the innermost corona is over 1000 times brighter than the outer corona), it is difficult to capture an image that resembles what the eye sees.
This photo is an effort to produce an image that captures to what I saw through 8x42 binoculars during the total solar eclipse of August 21, 2017.
It is a composite of 57 separate exposures (1/2000 to 2 seconds) shot with an Astro-Physics 105EDT refractor and a Nikon D800 DSLR. The images were combined and processed using Photoshop CC 2017 and Photomatix Pro 6. My PDF article "Digital Compositing Techniques for Coronal Imaging" is a bit dated (for example there is a discussion on digitizing negatives) but it still gives a detailed description of some of the digital processing techniques I used to process my 2017 eclipse images.
There is a tremendous amount of structure visible in the underlying data, but I have held back much of it to approximate what was actually seen visually and to avoid the heavily sharpened appearance that is common in HDR images. This version shows more detail than Visual Coronal 1A.
The Moon appears darker than the sky because of the huge contrast between the Moon's disk and the very bright inner corona adjacent to the Moon. I've tried to preserve this visual impression in this image. A custom Curves layer was used to approximated the color to the dark blue sky.
This image is available as a Custom Print.
Additional eclipse photos can be seen at: 2017 Total Solar Eclipse Photo Gallery.
For more information on this event, see: EclipseWise 2017 Total Solar Eclipse.
Technical Details
- Title: Visual Corona 4 - 2017 Total Solar Eclipse
- Date/Time: 2017 Aug 21 at 17:44 UTC
- Eclipse Circumstances: Altitude = 54°, Azimuth = 143°, HA = -1.41
- Location: Casper College, Casper, WY
- Mount: Losmandy G-11 German Equatorial Mount
- Telescope: Astro-Physics 105EDT Refractor (105mm, f/5.9, fl=616mm)
- Camera: Nikon D800
- Exposure: 1/2000 to 2 seconds, f/5.9, ISO 200
- File Name: TSE2017-T2cmp103-1Bw.jpg
- Processing (Adobe Camera Raw): Exposure Adjustment, Clarity, Sharpening, Noise Reduction
- Processing (Adobe Photoshop CC2017): Curves, Layers
- Rights: Copyright 2017 by Fred Espenak. All Rights Reserved. See: Image Licensing.
