Cooperative Institute for Research in Environmental Sciences
Friday, August 18, 2017

Coming Soon: 2017 Total Solar Eclipse Movie

CIRES researcher developed computer code to process thousands of eclipse path photos

Larisza Krista’s movie of the 2012 total solar eclipse in Queensland, Australia didn’t require a zoom lens, a solar filter, a tripod, or a video camera. Instead, it took computer programming and hundreds of still photos. Krista developed a tool to process solar eclipse images from many sources and stitch them together, to create a solar eclipse “movie.”

Image removed.
Interested in contributing to the 2017 Eclipse Megamovie citizen science project, powered in part by Dr. Krista's algorithm. Download the Eclipse Megamovie app on Android or iOS to take and upload photos.

And Google’s version of that tool is about to hit the big time: it’s part of a huge citizen-science effort to collect and process thousands of images taken by people along the path of the August 21 total solar eclipse. The Eclipse Megamovie Project—a partnership between Google, the Space Sciences Laboratory at the University of California Berkeley, and others, including CU Boulder and NCAR—will create a continuous view of the total solar eclipse as it crosses the United States, using a tool developed by Google, which is based on Krista’s Solar Eclipse Image Standardisation and Sequencing (SEISS) algorithm.

Images taken during the November 14 2012 total solar eclipse in Queensland, Australia, were processed with the Solar Eclipse Image Standardisation and Sequencing (SEISS) tool and used to create this short eclipse movie. Image: Larisza Krista/ CU Boulder and CIRES

“The algorithm we developed using the 2012 eclipse images was in preparation for this eclipse,” said Krista, a solar physicist with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, working at the NOAA National Centers for Environmental Information. Krista and her colleague Scott McIntosh, Director of the High Altitude Observatory at the National Center for Atmospheric Research in Boulder, created a program to process thousands of total solar eclipse images, taken by many people in many different places.

“The SEISS algorithm uses advanced image processing techniques to select high-quality solar eclipse images and prepare them for the eclipse movie sequence,” Krista said. Broadly, that process involves adjusting the images to a standard size, resolution, and orientation, and then ordering them to create a movie of an observed total solar eclipse. 

The starting point for the movie of the 2012 eclipse was about 200 images, including amateur and professional eclipse images, eclipse images of varying resolutions and orientations, and even some random non-eclipse images, such as holiday photos.

It was the SEISS tool’s job to make sense of those images. “Our goal was to process this database in the most efficient and automated fashion,” said Krista. “We developed an algorithm that would work on any images.”

The first step in processing the images was to identify the solar disk—the Sun—in the eclipse images. The next step was to standardize the images, so they were uniform in size and alignment or orientation.

Image removed.Image processing of the “diamond ring” phase of the 2012 total solar eclipse (in this example, the first glimpse of the Sun after totality). Left: a raw photo of the diamond ring phase. Middle: the analysis of the image. The purple contour shows the circle fitted to the solar disk (the ring); the pink contour highlights the identified diamond feature; the green line connects the disk center to the diamond centroid and allows the determination of the inclination angle and the diamond width. Right: the final, standardized image. Image: Larisza Krista/ CU Boulder and CIRES

Finally, the algorithm sorted the images according to time: “By analyzing the geometry and eclipse phases, we can determine the temporal order of the observations, then put them in the right sequence to create a movie of the observed total solar eclipse,” Krista said.

Image removed.An illustration of the aligned and time-ordered solar eclipse observations. Image: Larisza Krista/ CU Boulder and CIRES        

When Krista tested the SEISS algorithm with the 200 images from the 2012 total solar eclipse, it successfully processed them and created a short eclipse movie. After next week’s eclipse, Google will use a version of that code, modified to run on their servers for the Eclipse Megamovie Project, to process the estimated 10,000 images expected to come in.

“If you’re standing at one point along the eclipse path, you’ll see about two minutes of totality,” said David Konerding, a Google software engineer working on the project. “But imagine that you have people spread across the country along the eclipse path, taking photos of totality at each point. What you’ll get is essentially a cross-section of totality across the United States.”

By connecting with observers all along the eclipse path (you can sign up here, download the free mobile app, and follow the team online), including amateur astronomers and volunteer photographers, the Eclipse Megamovie team hopes to collect and assemble those thousands of images of the totality taken during the event. The end result will be the Eclipse Megamovie, a high-definition, time-expanded video of the August 21 total solar eclipse. This project will provide a treasure trove of data that far exceeds what any one person could gather from a single location.

A solar physicist by training, Krista also has a science experiment planned for the eclipse. She’ll be collaborating with Eclipse Megamovie to collect science-quality images along the eclipse path. “If we have good weather, we’ll be able to see the corona during totality,” she said. The corona is the Sun’s outer atmosphere, much dimmer than the bright light of the Sun’s surface. Rarely visible, it has its chance to shine during a total solar eclipse. The researchers will study the corona over the entire course of the eclipse path, to better understand its structure and how it changes over time.

The scientists involved in this effort have assembled a team along the eclipse path to collect and submit high-quality images. With those images, Krista and her colleagues will be able to study features of the corona including streamers, solar prominences, and loop structures. And “an erupting prominence, ejecting solar plasma into interplanetary space, would be amazing to see during the eclipse,” said Krista, “but the odds of that are very low.”