This image tracks the progress of the sun across the sky as it is progressively covered and uncovered by the moon. Here’s how this image was created.
The tripod mounted camera had a 17-40mm lens set at 17mm. From the information provided in this article I knew a 17mm focal length on a full sensor camera body would give me more than enough coverage to capture the entire eclipse as the sun moved across the sky from left to right. The lens had a white light solar filter from Thousand Oaks Optical which gives a nice, yellow-amber sun. I used a Canon TC-80N3 remote controller set to capture an images every five minutes for a total of 40 images. Once I started the timer I didn’t need to touch the camera again until the eclipse was over.
I didn’t want to mess with taking the filter off the lens during totality and changing the exposure setting. That would risk moving the camera and take up too much precious totality time. So I took the totality image the of the black sun and white corona with a different camera and lens with no filter.
A composite image of the sun moving across the sky needs a background. I used the same camera and 17-40mm lens that I used for the timed sequence and took the background image the night before the eclipse after the sun had set.
So there are 38 images of the sun (photographed with a filter) with camera A, the background image (no filter used), also taken with camera A, and the totality image (no filter used), taken with camera B, for a total of 40 images.
I put it all together using the information in this article. I put the 38 images together first, and saved the image with all 38 layers. Then I flattened the image. Before flattening, the image is 5.07 GB. That is such a big file size that it exceeds the file size limit for a PSD file, so I saved it as a PSB file (which is the big version of a PSD file).
Then I added the totally eclipsed sun and corona image and dropped it right in the middle of the other sun images. Lastly I dragged the entire sun sequence and dropped it on to the background image.
The Great American Eclipse Series