Picturing the Cosmos: Hubble Space Telescope Images and the Astronomical Sublime
by Elizabeth A. Kessler
University of Minnesota Press, Minneapolis, London, 2012
280 pp., illus. 59 col. Trade, $60.00; paper, $29.95
ISBN: 978-0-8166-7956-0 ; ISBN: 978-0-8166-7957-7.
Reviewed by Stephen Petersen
With their saturated colors and hyper-realistic detail, along with their promise of revealing the unseen universe, the images from the Hubble Space Telescope, launched in 1990, have a unique place in our visual culture. They are at once unprecedented—looking out into distant space and back into cosmic time—and commonplace—featured in calendars, screen savers, and posters. Rarely is their existence as visual objects probed: how did they come to be, why do they look the way they do? In this illuminating study art historian Elizabeth Kessler investigates them from a variety of perspectives, focusing not on the cosmic objects in the images, but rather on the images themselves as representations—and as such part of a history that includes astronomical illustrations, landscape paintings, and fine-art photographs.
Finding a special affinity between the Hubble images and pictures of the American West produced in the context of 19th-century geological survey expeditions, she notes the similarity between the cosmic formations in high-profile Hubble images and the buttes and cloud banks in Romantic landscape paintings by Albert Bierstadt, Thomas Moran, and others. Common to both kinds of images is a sense of atmospheric drama suggesting the sublime—the aesthetic category associated with awesome and overwhelming natural phenomena. The resemblance of the Hubble images to Western landscape pictures, both paintings and photographs, goes beyond appearances to a common American ideology of exploration. Both types of images also serve to offer a visual record of exploration to a broad public whose support the very undertaking requires, effectively becoming a public relations tool (the Hubble Heritage Project, highlighted throughout the book, is effectively a publicity arm of the space telescope program, charged with making evocative images for public release).
In their appearance, the Hubble images draw specific inspiration from the mid-20th-century photography of Ansel Adams, who synthesized the informative 19th century geological survey photography of William Henry Jackson, Timothy O’Sullivan, and Clarence Watkins, and the more fictionalized and dramatized work of the Western landscape painters. Adams produced highly detailed yet atmospherically expressive images that convey the spirituality of the uninhabited wilderness in theatrical fashion; immensely popular, his photographs have found a ready market in mass reproduction (much as, Kessler notes, have the Hubble images).
Conducting numerous interviews and doing extensive archival research, Kessler analyzes in depth both the production and the reception of the Hubble images. She reveals the myriad technical procedures used and choices made by the “image specialists” who take the telescope data (much of it based on light invisible to the human eye) and transform it into pictures. Decisions abound, concerning rotation, cropping, format, contrast, and color (including deciding which colors will correspond to which subsets of data); meanwhile, multiple raw images (both different angles of view and different spectra) are combined and cleaned up using manipulation software such as Photoshop, in the end synthesized into seamless wholes. “Artifacts” of the instrument – uneven exposures, glare and streaks, cosmic rays, seams between raw images, irregular frames – are eliminated (the one exception being the characteristic diffraction spikes from bright stars, an effect of the telescope that is not only retained in the images but is sometimes added). With evidence of the instrument eliminated, and done so by means of multi-layered image-processing techniques that are themselves undetectable, the Hubble images impart the illusion that we are looking at the phenomena themselves, unmediated. But, as Kessler shows, just the opposite is true.
Although wildly popular with the public, the images have had an ambivalent reception in both the scientific community, where they have little usefulness for study, and the press, where some critics have found their artifice, including their “false color” (as it is unhappily phrased), suspect. (Because they represent invisible wavelengths of light, their color is invariably arbitrary or “false”; there is no “true” color.) Meanwhile, as Kessler notes, the need to appease both astronomers, who tend to see the images as needlessly “pretty” but nonetheless appreciate their power to inspire, and also a broad public, who want to believe in the images’ veracity, has ended up restricting the choices made by the image specialists who produce the final Hubble images. The images are aesthetically conventional in many respects, relying on centuries-old pictorial formulae despite their far-out, never-before-seen subject matter.
Their method of production was, however, groundbreaking at first. The Hubble images are among the earliest examples of fully realized digital photographs. From its planning stages the Hubble relied on charge-coupled devices or CCDs in place of photographic plates or television receptors, resulting in a digital (i.e., numerically coded), rather than an analog image. In the intervening decades CCDs formed the basis of consumer digital photography. Unlike photographic plates they take a pixel-by-pixel reading of their subject. This leads to a paradox: whereas in the past, astronomy has derived data from photographic plates, here accurate readings of light intensity and wavelength are taken directly by sensors – resulting in a numerical data set that must then be converted into pictorial form to be seen as an image at all. “The Hubble’s views of the cosmos are doubly mediated,” notes Kessler, “translated first from celestial objects into data and then translated a second time [through a variety of applied software programs] into images” (p. 129).
Although astronomers typically now work from their offices analyzing photometric data obtained remotely from automated telescopes, Kessler notes that a century ago astronomers themselves ascended to remote California mountaintops, the landscape of the aesthetic sublime, to set up telescopes and make their observations, often under extreme conditions. The residue of this tradition might still be found in the extreme scenery of the Hubble images: “Their resemblance to mountain scenes reflects scientific practices that in the recent past brought together the landscape and the spacescape” (p. 197). How we see the universe today is colored by earlier ways of seeing, and imagining, not only outer space but the terrestrial landscape.
In the end, Kessler has more to say about the inherent message of the images (and the visual manipulations that help shape that message) than about their medium of distribution, namely the digital file, which remains a suggestive topic. The Hubble images are made for digital display and potentially endless reproduction in multiple sizes and formats – they can be copied, shared, manipulated, printed, and, in the many high-resolution examples freely available to the public, explored in great detail at high levels of magnification by anyone with a personal computer. This ability of a viewer to navigate almost ad infinitum within the image itself differentiates a high-resolution digital file from a traditional photographic image where, as exemplified in the 1966 film Blow-Up, enlargement entails a corresponding loss of resolution—not so with the biggest Hubble images.
Beyond the scope of this book, but worth exploring as well, is how the crafting of the Hubble images relates to contemporary digital photographic production in both the commercial and the artistic spheres. For example, fine-art photographers such as Jeff Wall and Andreas Gursky use image-processing software to craft elaborate composite photographs from multiple source images, seamlessly stitching them together into large-format tableaux, in a manner very similar to the method employed for the Hubble pictures. The very notion of an “image specialist,” used to describe the team members who work up the Hubble images, might well apply to practitioners of digital photography more generally, now that Photoshop or other image-manipulation programs are part of the production process for all kinds of photographs. In this respect, as in so many others, the Hubble images are truly of our age.