Navigate to [https://afterglow.skynet.unc.edu/en/workbench](https://afterglow.skynet.unc.edu/en/workbench)

Adjust your image so you can see the moons and the planet easily.

Click once on the moon and let go of the mouse button.

Click near the center of the planet and let go of the mouse button.

Scroll down in the Plotter tab and you'll see the length of the line you just made. Copy the length in arcsec to your assignment.

Begin again with your next image. Don't forget to turn off "Planet centroiding" before clicking on the moon.

Afterglow: Measure the Angular Separation of a Moon