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Total Solar Eclipse Animation in HDR: Prominences, Coronal Loops and Streamers, Rick Veregin

Total Solar Eclipse Animation in HDR: Prominences, Coronal Loops and Streamers

Acquisition type: Lucky imaging
Total Solar Eclipse Animation in HDR: Prominences, Coronal Loops and Streamers, Rick Veregin

Total Solar Eclipse Animation in HDR: Prominences, Coronal Loops and Streamers

Acquisition type: Lucky imaging

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Acquisition details

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Description

Understanding the motion during totality
  • Each time point was aligned on the moon, so the Moon appears stationary.
  • Thus, the Sun moves, along with its prominences and corona, from the upper left to lower right.
  • In reality of course, both Sun and Moon are moving West toward sunset, with the Moon lagging due to its orbital motion to the East, so the Moon passes over the Sun from right to left.
  • Prominences on the top/north appear to get smaller as they move down/right, as the moon covers them, while prominences on the bottom/south appear to get larger.
  • Prominences to the left/east disappear in time sequence, while those on the right/west grow. At the end of totality, Bailey’s beads, as well as the Diamond ring, pop out on the right.
  • Aside from the relative Moon/Sun motions, there appears to be some subtle changes in the corona within the 3 minutes. Generally, one doesn’t expect much change in such enormous structures, in such as short time.

Imaging in SharpCap
  • I ran a sequence of 9 different exposures (0.5, 1, 3, 10, 30, 100, 300, 1000 and 2000 ms at gain 200), which on average were a little over 2 seconds apart.
  • The sequence was repeated 9 times over the course of 3 minutes of totality, so I had 62 images to process (1000 and 2000 ms were too overexposed to be useful in the HDR).
  • Bailey’s Beads and Diamond Ring images were taken at 0.5 ms and 1 ms exposure, respectively, these single images were pulled out of the exposure sequences.
  • I collected 16-bit color fits files to maintain maximum data integrity. I could have collected 16-bit tif files, but in trials beforehand tif debayering was giving me odd results. Fortunately, I had worked the process out before eclipse day, so I knew fits files would work.

Deep Sky Stacker Processing
  • I “stacked” each fits file separately. DSS debayered the image, registering zero stars, but still “stacked” to a 32-bit tif. This was a simple, fast way to debayer without losing any quality.

Photoshop
  • I converted to 16-bit images.
  • HLVG was a fast way to remove the overall green cast, it worked like a charm.
  • For each image I did the same color and curves adjustments. I found this gave me a better HDR effect and color than using the as-is “raw” images.
  • Manually I aligned all images in the sequence, saving each sequence as a 16-bit tif.
  • In PhotoMatix Pro, I tone mapped each image sequence using Tone Compression, for a natural look. Tone mapping is wonderful, but it can produce some pretty fantastical results without care.
  • I used APF-R, which is a multi-scale unsharp mask (used by NASA), to remove blurriness in the final HDR image.
  • I then used a Radial Blur unsharp Mask to accentuate the detail further (Radial Blur>Spin 3>Apply Image>Subtract (Offset=128)>Levels (100,1,156)>Overlay 33%)
  • I did noise reduction using NoiseXterminator on the final HDR image.
  • HDR showed a weakly Earth-lit new moon, with a few vague details. There was too much scattered light for a good image, so I darkened the moon with curves.
  • I repeated these steps for all 9 image sequences!


Animation of the image sequences in Photoshop
  • All nine HDR images were loaded and aligned manually.
  • I did levels/curves adjustments to level out brightness and contrast variations in the sequence.
  • I used Tween to add 2 intermediate images between each image in the sequence, to smooth out the animation. A huge shoutout again to @Darkstar  who showed me how to Tween, when everyone on the internet said that what I wanted to do,could not be done in Photoshop. I am forever grateful!
  • The result is 23 frames representing 3 minutes in real time, so about 8 s realtime per frame.
  • The final image sequence was saved as a gif at 50% resolution, to make the size manageable.

Thus, weeks later, exhausted, I am done. I did not realize how big this project would be…

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