Astronomical

NASA Goddard:

The top right photograph shows Neptune’s ring system. Each half of the image represents a single 591-second exposure, taken with a clear filter. Neptune’s rings were too faint to register if Neptune itself were in view, evidenced by the overexposure at the inner edge of both halves of the image due to the planet’s much greater brightness.

In the middle image, the evolution of Neptune’s weather is visible over a period of thirty-six hours, spanning two revolutions of the planet. This series of three photographs, each taken eighteen hours apart, documents changes in the clouds of frozen methane surrounding Neptune’s Great Dark Spot (a storm system with roughly the diameter of Earth).

Voyager 2 is the only spacecraft to encounter Uranus and Neptune up-close. It discovered ten previously unknown satellites of Uranus and six of Neptune. The views captured nearly three decades ago by Voyager 2 remain the best images of both outer planets.

The bottom image presents two views of Uranus’s pole of rotation, one a true color image constructed from blue-, green-, and orange-filtered photographs; and the other a false color image that exaggerates the atmospheric variations at the pole. In the view on the right, ultraviolet-, violet-, and orange-filtered data were coded, respectively, as blue, green, and red. The view reveals a dark haze or “hood” over the pole, which gives way to progressively lighter convective bands moving toward the equator. The contrast between the bands shown here is computer-enhanced, making subtle variations in Uranus’s atmospheric composition appear stark.

The top left view depicts all nine of Uranus’s known rings in false color. The brightest and furthest ring from Uranus is at right in this photograph. Color averages were taken from two sets of images made with green, clear, and violet filters in order to determine the correct color relationships between each ring. The bright lines are the rings, while the fainter pastel bands are relics of computer enhancement.

These image from Lunar Orbiter 1 are two of the first ever “Earthrise” photographs. The unplanned, over-the-shoulder view was initiated by Dale Shellhorn, a University of Arizona-trained astrophysicist. It shows the arc of the setting Sun, called the “terminator,” which spans from Antarctica on the left-hand side in this image, to Britain on the right. While it was not the first image of our planet seen from space, this photograph, with the Earth dwarfed by a profoundly alien landscape, captivated the public upon its release. Reactions to it echoed those of several Apollo astronauts who reported pangs of overwhelming homesickness when seeing their distant planet from the Moon.

The Lunar Orbiter program was initiated to scout potential landing sites for manned flights to the Moon. Five unmanned Lunar Orbiter flights collectively imaged 99 percent of the lunar surface at a resolution of two hundred feet or better. The Lunar Orbiter spacecraft carried a camera system unlike any other in the history of the U.S. space program: it comprised two film cameras, one high- and one moderate-resolution, which used conventional gelatin-based negatives. Exposed negatives were automatically developed onboard, and then scanned and relayed by radio to Earth. Many Lunar Orbiter pictures, including some here, contain bubbles or other flaws resulting from uneven chemical processing.

Lunar Orbiter images were used in conjunction with those from Surveyor. By cross-referencing ground-level and aerial views of the lunar topography, scientists could determine distances and elevations with accuracy. A group of photographs made by Lunar Orbiter 3 allowed UA astronomer Ewen Whitaker to pinpoint the landing site of the unmanned Surveyor 3 in an ancient lava field. The area was so ideal that the Apollo 12 lunar module, the second manned spacecraft sent to the Moon, touched down less than two hundred yards from the deactivated Surveyor 3, allowing its crew the proximity to make portraits of their robotic forerunner.

The Whole Earth Catalog was, in its own words, like “Sears Roebuck or Consumer Reports, merely attuned to a new market, the sub-economy of dope and rock.” In truth, it was much more. The brainchild of video artist Stewart Brand, the Catalog was a distribution mechanism for tools and literature that promoted sustainable living. It espoused radical visions of architecture and design, media and communications theory, and community practices, from luminaries like Buckminster Fuller, Marshall McLuhan, and Wendell Berry. From its first issue in 1968 to its final one in 1971, the Catalog operated as a community in print that connected dispersed countercultural groups, from scientists to survivalists. Steve Jobs once called it “Google in paperback form.”

The Ranger program was NASA’s first attempt to send spacecraft to the Moon. Unmanned Ranger craft were intended to crash-land onto the lunar surface, transmitting images up until impact. On July 31, 1964, after six failed Ranger flights, NASA’s Ranger 7 successfully relayed over four thousand images of the Moon back to Earth. The craft crash-landed into an area of smooth volcanic rock on the Moon’s near side, later dubbed Mare Cognitum (Known Sea) in honor of the mission. The last few photographs from Ranger 7, taken seconds before the spacecraft hurtled to its demise, had a resolution nearly one thousand times greater than any that had been achieved with Earth-based telescopes.

Returning high-resolution images was one of the main objectives of the Ranger program. Rangers 6 through 9 were equipped with a bank of six television cameras with varying focal lengths to provide both wide- and narrow-angle views. The cameras exposed images in the form of electrical impulses onto photo-sensitive metal plates, which were then scanned, converted to radio signals, and transmitted to Earth. Once the images reached Ranger Mission Control at the Jet Propulsion Laboratory in Pasadena, California, they were recorded onto film. The images returned by Ranger 7 gave NASA scientists their first confirmation that there were lunar areas that could be used as sites for manned landings. Rangers 8 and 9 would take some twelve thousand more pictures, offering unprecedented insight into the composition of the Moon’s surface.

Over the course of six moonwalks, the Apollo astronauts brought back 842 pounds of rocks, dust, and core samples from the Moon. After splashdown, lunar rock samples were taken to NASA’s Lunar Receiving Laboratory in Houston, Texas, where they were processed and analyzed.

NASA scientists examined thin slices—about one-thousandth of an inch thick—of the lunar rock samples under a petrographic (literally “rock-recording”) microscope. The left photomicrograph was taken using regular transmitted light. The right one was made under cross-polarized, or “crossed Nicols” light, produced by passing light through two perpendicular polarizing Nicols prisms before it reaches the sample. Holes look black, while the minerals that make up the sample appear vibrantly colored, allowing scientists to identify the rock’s individual components by color.

The Apollo astronauts’ bulky suits, along with the moon’s weak gravity, made the simplest movements tiring and awkward. To conserve time and energy, the act of photographing was simplified as much as possible. While the astronauts were equipped with handheld Hasselblad cameras, during moonwalks the cameras were mounted to chest brackets on their suits. Because sunlight was so bright during the lunar day, the astronauts kept their cameras at a fixed small aperture setting, allowing for great depth of field. Film was wound automatically with a motor drive, and the shutter was controlled by a trigger mechanism. Since the astronauts could not afford to take extra weight on their return trip to the command module, they left their Hasselblads, with custom Zeiss lenses, on the surface of the Moon.

Moon dust, each granule a relic of millions of years of shattering impacts, reflected light unpredictably. (The dust also clung to any surface it touched, including space suits, camera lenses, and instruments; once embedded, it was nearly impossible to remove.) For a visual reference point, the Apollo astronauts carried color charts that they photographed on the lunar surface.

Apollo astronauts faced a landscape marked by colossal forces, yet one of eerie clarity and unusual actions of light. Because the Moon has practically no atmosphere to refract light, the sky was a palpable, velvety black during the day, while the Moon’s surface appeared floodlit. Moon rocks that on Earth would look charcoal-colored were instead a bright, silvery gray.