The Citizen Continental-America Telescopic Eclipse (CATE) Experiment

2017 Data and Results


The Citizen Continental-America Telescopic Eclipse (CATE) Experiment was a unique citizen science experiment designed to capture a 90 minute sequence of white-light coronal observations during the August 2017 total solar eclipse. Using identical instruments at 70 observing sites, the CATE group imaged the inner corona from the surface of the sun out to 2.1 solar radii, with an image scale of 1".43 per pixel and at a cadence of one high dynamic range image every 2.1 sec

The Citizen CATE Experiment was funded by a combination of federal, corporate and private contributions, and involved volunteers from middle school students through professional solar astronomers. These volunteers collected data at observing locations in the path of totality from Oregon to South Carolina. After the eclipse, the site volunteers were granted full ownership of the CATE equipment, and several groups continue to use the equipment for scientific, educational and outreach projects today.

The image sequence produced by the Citizen CATE Experiment shows things never seen before during a total solar eclipse. A scientific paper measuring the acceleration of a coronal mass ejection plasma in the inner corona using white light has already been published. The data contains other fascinating one-of-a-kind observations of polar plumes, a chromospheric surge, and coronal streamer evolution. As the first analysis of the data from the citizen science team nears completion, several new scientific works are expected to result from the beautiful movie of the inner corona produced by the CATE Experiment.


2019, Acceleration of Coronal Mass Ejection Plasma in the Low Corona as Measured by the Citizen CATE Experiment, Publications of the Astronomical Society of the Pacific, Volume 132, Number 1007,

2016, Instrumentation for the Citizen (CATE) Experiment: Faroe Islands and Indonesia,


The following is an animation of all CATE sites that collected data on 21 August 2017: CATE_mov.gif

The movie is an animated gif with a single averaged HDR frame from each CATE observation site. It represents approximately 90 minutes of totality showing coronal evolution over this time. Note, the movie is aproximately 80MB in size and may take time to download the first time.

Movie Key
We can highlight some of the items that you can see in the movie. We consider that the lunar image is a clock-face and discuss items moving clock-wise from the top of the image. Click on the image above to open a full size key in a new window.

– At roughly 1 -o'clock you can see the star HD86898 appearing to move in the sequence behind the solar corona.

– At roughly 3 -o'clock there is a very large prominence that shows only small changes during the 90 minute sequence. Just below this prominence is a chromospheric surge, which propagates up into the solar corona and moves outward.

– At roughly 5 -o'clock there is a very fast polar plume moving away from the Sun in the early part of the eclipse.

– At roughly 7 -o'clock there is a large and complicated outflow which follows a coronal mass ejection that occurred just before the start of the solar eclipse. Here you can also see the star GM Leo moving behind the solar corona.

– At roughly 10 -o'clock you can see a small prominence that changes a lot during the eclipse, and you can see a small loop-type of eruption move out of the coronal streamer positioned above that prominence.

– At roughly 11 -o'clock you can see a rapid polar chromospheric surge appear in a few frames of the movie.


Averaged HDR FITS files of all sites may be downloaded here as a compressed tar archive. The file size is 621MB with an MD5 checksum of: af763f574aff2dc330bcc72b727b6880. cate_sites_avgHDR.tar.z

The raw data is complicated and is over 1TB in size. A copy of the raw data can be obtained by sending a 2TB drive, postage prepaid to Bob Baer. Contact for details.


The CATETool source is available on github at: catetool source code

Ongoing Observations

For a list of current observation projects from this team, see the Dynamic Eclipse Broadcast (DEB)\ Intiative.


The CATE team gratefully acknowledges financial and multi-site equipment support from Jen Winter (Daystar LLC), David Garrison (Mathworks, Inc), Corey Lee (Celestron LLC), and Stephen Lauro (colorMaker, Inc). The CATE team appreciates the site equipment support from Rosamond Kinzler of the American Museum of Natural History and from Bill Kloepping. The CATE team acknowledge Research Corporation for Science Advancement award 24174, NASA Cooperative Agreement NNX16AB92A, NASA award NNX17AH76G, and NSF award 1732227. D.W. acknowledges NSF award 1901296.

Contact Information

Project PI: Dr. Matt Penn, email

For web or data download issues, email Mr. Bob Baer,

Use of materials on this site should be credited to, "Penn et al 2020 PASP 132 014201 and the DEB Team."