Basically, we traced a circle on square paper with chalk and then added additional color. We watched the footage of the eclipse as it happened all over the united states and we looked at examples through photos of the corona taken throughout historical eclipses by artists. We also practiced color blending with chalk.
(Idea stolen from here)
Resource for photos of historical corona's here.
I demonstrated how to use the circle template as a mask and then pull the chalk away to create that glowing effect. I had lots of sizes of circles for students to choose from.
chalk pastels (organized in bowls as hot or cool colors)
12X12 or 9X9 black paper
variety of circle templates