Photographers, get ready for the 2017 solar eclipse!

Continuing the trend of somewhat unusual astroph papers, today I’ll discuss an interesting white paper that went up two weeks ago.

• Title: The U.S. Eclipse Megamovie in 2017: a white paper on a unique outreach event
• Authors: H.S. Hudson et al.
• First Author’s Institution: SSL, UC Berkeley; University of Glasgow

Figure 1: The path of totality across the US for the 2017 solar eclipse. Image from http://www.eclipse-maps.com. Fig 1 in the paper.

Introduction
In 2017, much of the continental US will be witness to a solar eclipse that travels across the country (see Figure 1). An event like this is bound to attract quite a bit of public attention. Thus, what better time to do some citizen science?

This white paper is a call for organization of a major citizen science project during the 2017 solar eclipse: the creation of an eclipse “megamovie.” The goal is to get observers of the eclipse across the US to take photographs of the eclipsed Sun and submit them to the project for compilation into a high-resolution movie. The authors point out that if 10,000 observers each take 100 frames, at a standard frame rate this would produce a 12-hour-long slow-motion movie of coronal evolution. This would be the first time a solar eclipse has been tracked with high time resolution for a period of time longer than the duration of totality at a single location.

The Execution
Obviously, compiling on the order of a million images into a roughly uniform movie is an enormous challenge. Due to the large volume of data (the authors anticipate roughly 10 TB), this process of matching the scale, orientation and general histogram data would need to be automated.

The authors cite previous work by Miloslav Druckmüller and his collaborators as evidence that automating such a pipeline is possible, and point out the website astrometry.net as an example of software that performs similar calibrations for star fields. Dealing with the data is possible, they argue; we just need to put some effort into developing the techniques for this particular application.

The Outreach Payoff
The Megamovie project would be a fantastic opportunity for public education and outreach. The interest in the eclipse will draw an audience that might be otherwise unreachable, and project members will then have the opening to educate these people about the science to which their data will contribute.

The project can seek broad participation from school programs and community groups of all levels, and this can also be used as a chance to get minority groups involved.

Figure 2: Two images taken roughly 1.5 hours apart during the 2010 eclipse. Several features from the corona can be identified and their evolution and motion between the two frames is visible. From Pasachoff et al. 2011; fig 2 in the paper.

The Science Payoff
The eclipse Megamovie, while it sounds like a somewhat whimsical idea, would be breaking new scientific ground. As already mentioned, this degree of time resolution is unprecedented in solar corona observations. Furthermore, some percentage of the people involved are likely to take high-spatial-resolution photographs, which should exceed the quality of most spaceborne coronagraphs (LASCO/C2 only has a spacial resolution of 11.2”, for comparison).

The Megamovie project would allow for continuous monitoring of coronal evolution and dynamic activity, including variations in the low corona, a domain not accessible to space-based coronagraphs. It would also capture associated prominence systems at high resolution for an extended period of time. An example of what would be possible is shown in Figure 2, which contains two images taken during the 2010 eclipse.

Another scientific aspect this project could address is a verification of the gravitational deflection of starlight by the Sun. The authors are unaware of any successful repetition of this experiment, which was performed in 1919 by Sir Arthur Eddington — without the use of modern CCD cameras.

Conclusion
The authors of this white paper propose that organization of the eclipse Megamovie project begin immediately in spite of the eclipse not occurring until 2017; an upcoming eclipse occurring in Australia in 2012 will provide a convenient test of this proposal and software developed to process the photographs. Thus the authors suggest that now is the time to start work on the calibration software, as well as start to publicize the project and prepare education and outreach materials.

If all goes according to plan, the Megamovie project will be a clever and unique way of taking full advantage of 2017’s opportunity.

About Susanna Kohler

I received my BS in physics from University of California at Santa Barbara in 2008 and my PhD in astrophysics from University of Colorado Boulder in 2014. My dissertation work focused on studying and modeling the extremely energetic outflows from active black holes at galactic centers. I now work for the American Astronomical Society, as the editor of AAS Nova.

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