© NASA
NASA astronaut Don Pettit offered unique perspectives on photographic technology and the beauty and challenges of space photography in his keynote address at PhotoPlus Expo on October 24. Pettit, who has spent more than a year in space as part of three missions to the international space station, shared a few of the thousands of images he has taken from above the earth’s atmosphere, including breathtaking time-lapse images of the aurora borealis and other natural and manmade phenomena. He also described some of the ways he’s had to adapt to the unique challenges of shooting in what he calls “a frontier environment.”
On earth, for example, photographers don’t have to worry about “cosmic ray damage” to the CMOS chips in their cameras causing noise and spots in their images. Photographers on earth don’t have to account for the shift and speed of a spacecraft that completes an orbit of the earth every 90 minutes. When shooting through one of the windows on the space station’s cupola, Pettit has to deal with multiple reflections, because each window is made up of four panes of glass several inches thick. To block the reflections of the “nasty blinking things” on the control panels, he has created what he calls “my turtleneck.” He drapes a large black cloth over all the control panels. The cloth has a hole in the middle that’s big enough for him to poke his head through. He noted that the lavatory is located near the cupola; if the light is turned on, it’ll ruin a long night-time exposure. “I’ve trained the crew to pee in the dark.”
Pettit, a self described “uber geek,” showed a photo of the dozen or so cameras set up within the cupola. In the weightless environment, he can also attach the cameras to his clothes with Velcro. The cameras are always on, he said, because when a crew member sees something to photograph, the camera has to be ready or the moment is gone until the space craft returns to the same orbit track 11 days later.
While he favors wide-angle lenses when shooting the interior of the space station, telephoto lenses allow him to photograph areas on earth with far greater detail and fidelity than found in satellite images, which are typically stitched together from several images. From the space station, Pettit has been able to get “a continent-long perspective” on both natural and manmade phenomena. He has captured the lights of cities, for example, from Boston to Washington, and along the length of the Nile River. When he showed an image of New York City with a bright spot glowing like an ember in Manhattan, he said, “There are people in midtown who never sleep.” The images were made possible, he notes, by improvements in cameras that work at far higher ISO ranges than in years past. He showed a device he fashioned from several parts, including a handle that allows him to control the shift and compensate for the movement of the spacecraft during long exposures.
In some photos that were shot on minute-long exposures, glowing white spots appear on the earth below. These were thunderstorms, Pettit explains; at a recent talk, an audience member told him he was using lightning as fill flash. Pettit has used the same long-exposure techniques that amateur photographers use to capture trails of stars as the earth spins; in Pettit’s space photos, however, the stars trace concentric circles in the top of the frame while the bottom of the frame is filled with colorful ribbons of light made by city lights. He also captured air trails from jets, which look, he said, “like the trails snails leave in your garden.”
Pettit ended his talk with a series of time-lapse videos that a colleague made for him by putting together thousands of images shot a second apart. These images show the mysterious green lights of the aurora borealis whirling and swirling near the arctic as the earth rushes by below the space station.
Pettit told the audience that he often faces “the photographer’s dilemma”: whether to shoot photos that will appeal to “earth-centric people” or to show the environment as it really is. He showed, for example, a posed group shot of Pettit and his crewmembers taken at the request of NASA. With the crew seated in two rows, only the floating ponytail of a female astronaut indicates that they are in a weightless environment. In reality, Pettit said, “you have people working around you oriented at all angles.” In his talk, Pettit demonstrated that he has been able to resolve the dilemma by showing earth-bound people things they will never see in a way that is both beautiful and awe-inspiring.