A long lens was used by astronauts aboard the International Space Station to take this photograph highlighting many natural and built features around Cancún. The street pattern of this Mexican tourist mecca contrasts with the waterways of the marinas that open into the bay and the lagoons. And the brilliant blue water over coral reefs contrasts with the dark waters of inland lagoons. The reefs are part of the second largest reef system on Earth, and they draw tourists from all over the world.
The wide, well-developed white-sand beach on the Gulf Coast is the result of vigorous wave energy. But wave energy is reduced along the protected shoreline closer to the city (image center), and the beaches are thin or non-existent. Fair-weather cumulus clouds are scattered across the top left of the image.
To shoot crisp images with long lenses, astronaut photographers must learn to brace themselves against the ISS bulkhead to prevent any slight shaking that would blur or smear the picture. Counterintuitively, they need to move the camera carefully keeping the target at the same point in the viewfinder because the landscape moves across the viewfinder quickly. This is called “tracking the target” and requires good coordination by the photographer to prevent blurring. Shorter lenses do not require this skill because the image passes more slowly across the viewfinder.
Astronaut photograph ISS040-E-112662 was acquired on August 30, 2014, with a Nikon 2Xs digital camera using an 800 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by the Expedition 40 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by M. Justin Wilkinson, Texas State University at NASA-JSC.
Chetumal Bay lies on the Border between Mexico and Belize. To the east of the bay, Ambergris Cay connects the Belize Barrier Reef to the Yucatan Peninsula. The north of the island is Bacalar Chico Marine Reserve. Here, the barrier reef comes very close to the east side of the island. In 1998, reefs in Belize were hit by two major events that led to heavy coral mortality: El Niño-related coral bleaching and Hurricane Mitch.
The Sudanese coast of the Red Sea is a well-known destination for diving due to clear water and abundance of coral reefs (or shia’ab in Arabic). Reefs are formed primarily from precipitation of calcium carbonate by corals. (In addition to its commonly used meaning, precipitation can also describe how something dissolved in a solution becomes “undissolved” through chemical or biological processes.) Massive reef structures are built over thousands of years of succeeding generations of coral. In the Red Sea, fringing reefs form on shallow shelves of less than 50 meters depth along the coastline. This astronaut photograph illustrates the intricate morphology of the reef system located along the coast between Port Sudan to the northwest and the Tokar River delta to the southeast.