Without protective gear, looking directly at an eclipse can cause serious damage or scarring to the eyes. “Solar retinopathy is a photochemical injury to your retina,” Dr. Nicole Bajic, a surgical ophthalmologist at the Cleveland Clinic, previously told TIME via email.

In contrast, during a total solar eclipse — which is preceded by a partial eclipse — the moon completely covers the sun, revealing the sun's outer atmosphere, called the corona, during totality. That's the only time it's safe to look at a solar eclipse with the naked eye, since all of the sun's light is blocked.

Its primary objective following the March 2 touchdown inside Mare Crisium crater was to deliver 10 NASA instruments designed to gather lunar subsurface data. But the eastern edge of the moon’s near east side also provided a perfect spot for viewing a solar eclipse from the moon’s point of view.