California Barrel Cactus

The California Barrel Cactus (Ferocactus cylindraceus) is one of three species of barrel cactus found in Arizona. As is the case with its relatives, it has a spherical shape early in its life. It assumes a more columnar aspect as it grows, however, and can grow to over six feet tall. This one was photographed in Maricopa County, Arizona near Stewart Mountain.

Earth’s shadow and the Belt of Venus

As the sun sets and drops below the western horizon, a shadow cast by the Earth itself rises on the opposite horizon. From the point of view of an observer facing east immediately after sundown, the Earth’s shadow is visible as a dull bluish band along the eastern horizon. Also visible, just above the Earth’s shadow is a second band, pinkish in color. This pinkish band is known as the anti-twilight arch, or, more colorfully, the Belt of Venus. This image was taken in Cochise County, Arizona, at 4,400′ with a clear and open view of the eastern horizon, with a moonrise thrown in for good measure.

Tuff Canyon

Tuff Canyon in Big Bend National Park, Texas, was carved by a stream originating in the nearby Chisos Mountains called Blue Creek. Tuff Canyon is named for the rock that forms the canyon walls. This rock is composed of deposits of volcanic ash which over time were subjected to pressure and became consolidated into their present form. “Tuff” is the term for this consolidated volcanic ash.

The Window

The Chisos Basin in Big Bend National Park, Texas, is nestled in the heart of the Chisos Mountains at about 5,400′ in elevation. It is surrounded by cliffs on all sides save for the gap known as The Window. It is a fitting name as it is on the western edge of the Basin and offers views of distant desert ranges and often frames beautiful sunsets. The Window is also the outlet for water draining out of the basin; such outlets are locally referred to as a pour-offs.