Astrophotography and Astronomical Imaging

P. Horálek/ESO, A Magical Night in the Atacama Desert/Milky Way, 2023.  Creative Commons Attribution 4.0 International License.

Astrophotography, or astronomical imaging, represents the convergence of science and art, capturing the universe through the medium of photography. It allows for the preservation of cosmic events while providing invaluable data that furthers our understanding of the cosmos. From its beginning as a rudimentary daguerreotype to the complex digital sensors of today, astrophotography has long served as a bridge between human curiosity and the universe. Not only has it propelled significant discoveries like exoplanets and black holes, but also has helped to reshape our perception of humanity’s place in the universe. 

The formal practice of astrophotography began in 1840, when John William Draper used a daguerreotype to successfully capture the first image of the moon. This achievement marked a pivotal moment, transitioning astronomy from purely observational to an image-driven science. By the 1860s, Warren De la Rue pioneered wet collodion plates, which are glass plates covered in collodion to capture images with its light-sensitive properties, showcasing the camera’s potential to outmatch the human eye in both sensitivity and permanence. [1] By the 1880s, Andrew Ainslie Common further pushed the boundaries of astrophotography, utilizing a 36-inch telescope with a mirror, creating a long-exposure method that would capture the Orion Nebula. These advancements mirrored the broader advancements in photographic technology, including the invention of dry plates and the enhancement of telescopic lenses, which collectively enabled more detailed and expansive images of the universe. [2] By the late 19th century, astrophotography had evolved into the premiere method for studying astronomical phenomena, setting a strong foundation for breakthroughs to follow.

Astrophotography revolutionized the scientific approach to space exploration with methods like long-exposure imaging. By capturing light from distant celestial bodies, astrophotographers have contributed to mapping the stars and measuring the cosmos in a way previously unimaginable. Notably, Edwin Hubble utilized photographic techniques to demonstrate that galaxies are indeed receding one another, which led to the groundbreaking discovery that the universe is expanding. [3] The development of modern image processing systems, such as the National Radio Astronomy Observatory Astronomical Image Processing System (AIPS), has further refined these images to transform raw data into scientifically accurate representations. [4]

Astrophotography, however, extends beyond the realm of scientific inquiry; it also reflects cultural narratives and our evolving understanding of objectivity. In the late 19th century, Edward Holden, director of Lick Observatory, praised photography for its perceived capacity to produce “objective” records devoid of human bias. He believed that astrophotography offered a means to depict the universe with a precision and honesty that hand-drawn illustrations could not and signaled a shift towards technology as a means to achieve unbiased observations. [5] However, as Mikael Pettersson argues, the notion of a purely neutral photograph is inherently flawed–every image is influenced by the choices made by the photographer and the technological limitations of the equipment. The tension between objectivity and subjectivity in astrophotography has revealed much about the ways in which our values influence our scientific practices and our desire to see the universe without human interference.

Astrophotography has also significantly shaped the emotional connection between humanity and 

the cosmos. Iconic images, such as the “Pillars of Creation” taken using the Hubble Space Telescope, are often used as an image to evoke awe, reminding us of our insignificance in the vast endless space. Nowadays, the widespread availability of digital cameras has expanded astrophoto, allowing amateur astronomers to contribute meaningfully to the field. Digital tools and software like DeepSkyStacker, now allow for layering of multiple exposures to create highly detailed composite images of celestial bodies, illustrating the continued interplay of art and scientific rigor in astrophotography.

In the present day, astrophotography continues to be an essential tool for both scientific inquiry and cultural expression. It has evolved alongside technological advancements, incorporating sophisticated sensors, adaptive optics, and artificial intelligence to improve the quality and scope of the images. These innovations have allied scientists to study phenomena like black holes, exoplanets, and distant galaxies. Moreover, astrophotography has become a way for people to engage with astronomy in an era dominated by digital connectivity, fostering communities of enthusiasts who share their insights. Ultimately, astrophotography is more than a method for capturing the cosmos—it is an indispensable instrument for scientific discovery, a well of artistic inspiration, and a testament for humanity’s desire to learn.

Endnotes

[1] Bob Riddle, "Imaging the Night Sky," Science Scope 37, no. 6 (2014): 86–91; Chaokang Tai, "The Milky Way as Optical Phenomenon: Perception and Photography in the Drawings of Anton Pannekoek," in Anton Pannekoek: Ways of Viewing Science and Society, edited by Chaokang Tai, Bart van der Steen, and Jeroen van Dongen, 219–48. Amsterdam University Press, 2019. 

[2] Klaus Brasch, “A Short History of Astrophotography,” Journal of the Royal Astronomical Society of Canada, April 2017. 

[3] Mikael Pettersson, "Shot in the Dark: Notes on Photography, Causality, and Content," The Philosophical Quarterly 62, no. 249 (2012): 759–76; Alex Soojung-Kim Pang, " “‘Stars Should Henceforth Register Themselves’: Astrophotography at the Early Lick Observatory," The British Journal for the History of Science 30, no. 2 (1997): 177–202.

[4] Eric W. Greisen, “The Astronomical Image Processing System Memo No. 61,” National Radio Astronomy Observatory, September 12, 1988.

[5] Pang, "Stars," British Journal for the History of Science.