Polaris Portraits

I created the drawing series Polaris Portraits in conjunction with writing my book Attention Is Discovery: The Life and Legacy of Astronomer Henrietta Leavitt (forthcoming in fall 2024 from the MIT Press). The book is a celebration of Henrietta Leavitt’s foundational 1908 discovery of the period-luminosity relation in Cepheid variables—a discovery that launched modern cosmology by enabling astronomers to measure the distance to faraway stars for the first time. But after her groundbreaking work with variable stars while employed at the Harvard College Observatory, Leavitt was assigned the task of standardizing photographic magnitudes—determining the brightness of stars as recorded by telescopes on glass plates—a seeming demotion from her earlier role. Yet this work was essential to making any investigative progress toward understanding the pinpoints of light in the sky, about which so little was known at the time. Establishing standards that could be shared and used by the international astronomical community was a central focus of the director of the Harvard College Observatory at the time, Edward Pickering. The period-luminosity relation, now known as the Leavitt law, made it possible to conceptualize our three-dimensional universe. But Leavitt’s work to standardize magnitudes is also significant, and examining this “ordinary” work reveals how extraordinary it actually was.

While I conducted research for the book and delved into Leavitt’s methods, it became apparent how inventive Leavitt needed to be as she tried to discern how starlight was mediated by a new photographic technology developed in the late nineteenth century. To standardize her North Polar Sequence—a sequence of ninety-six stars near the North Pole representing the widest possible range of brightness, which once established could be used as a benchmark for all other stars in the sky—Leavitt directed the creation of multiple-exposure photographic glass plates. This allowed bright stars, which would otherwise be overexposed during the longer photographic exposures required to capture fainter stars, to be in conversation with the midrange and faint stars in her sequence. Starlight was diffracted through the use of prisms, polarizers, diaphragms, and wire screens placed at the light-gathering end of the telescope to disperse or dampen the light of these bright stars before it contacted the photographic plate. With the light fractured or reduced by calculable amounts, Leavitt could then compare it to the known magnitudes of midrange stars shown in subsequent exposures taken without interference on the same plate.

My new drawing series is based on magnified details of how Polaris, the North Star, appears on plates Leavitt notated—plates that seem nondescript until close looking reveals the visually intricate, radically new world she studied. Leavitt learned to decipher how the nascent, fickle technology of dry plate photography translated starlight onto glass and applied that knowledge to orchestrate the making of these esoteric but meaningful photographs for her work on standardizing magnitudes. Polaris Portraits documents the ways starlight was diffracted, doubled, dampened, and diverted to bring bright, intermediate, and faint stars into relationship with one another on these multiple-exposure plates. Held in these drawings is Leavitt’s life spent looking, placed in conversation with my own time spent noticing. They remind us that the ordinary is always where the extraordinary lives.


Many thanks to Jennifer L. Roberts, who accompanied me on numerous research trips to the Harvard College Observatory’s Astronomical Photographic Glass Plate Collection and made the source photographs for these drawings using a macro lens. Roberts also contributed a guest essay to Attention Is Discovery and was a smart, intelligent, and wise first reader of the manuscript. I feel enormous gratitude for her collaboration in making this drawing series as well as the central role she has played as a part of my larger project on Henrietta Leavitt.


Many thanks as well to the people at the Harvard College Observatory plate stacks for the generous access to these materials and dedicated support.

Additional Bodies of Work