What Is the Afterglow After Sunset Called?

Afterglow is the general term for the warm pink, orange, and red light that remains in the western sky after the sun has set. It's caused by sunlight still illuminating the upper atmosphere and cloud from below the horizon. Afterglow typically peaks 5–15 minutes after sunset and fades over the following 20–30 minutes as civil twilight ends. This is the window most photographers specifically chase.

While watching the western afterglow, turn around and look east. The pinkish-purple band low on the eastern horizon — just above the rising blue-grey shadow of the Earth — is called the Belt of Venus (or Venus's Girdle). It appears opposite the sunset and is visible for 20–40 minutes after sunset. Most photographers miss it by keeping their back to the east.

The dark blue-grey band beneath the Belt of Venus is the shadow of the Earth itself being cast into the atmosphere. As the sun sets in the west, the Earth's shadow rises in the east. The Belt of Venus sits in the zone between the shadow and the lit sky above. Together they create one of the most distinctive post-sunset visual effects.

Alpenglow is the reddish or pinkish illumination that appears on mountain peaks and snowfields after the sun has set. It's caused by the same low-angle post-sunset light reflecting off high-elevation surfaces. Mountains facing east or northeast often show the most intense alpenglow as they catch the scattered post-sunset light. It's brief — typically 5–15 minutes.