<p>Humans' view of the universe has changed as our observational tools have changed.  Noticing that groups of stars travel in constellations, some stars appear only during certain seasons, and the Pole Star always points North in the northern hemisphere was possible with the naked eye. Through gradually improving telescopes and lenses, observers made drawings of what they saw until photography through telescopes made it possible to collect light over a long period and thus see stars invisible to the naked eye. Ever greater magnification and new instruments let scientists see that not all objects in the sky were stars - some were clouds of gas and "smeared out" objects which turned out to be other galaxies. Today we collect unprecedented imagery from spacecraft and earth-based telescopes in incredible resolution and varying wavelengths, allowing us an ever-better understanding of the universe around us.</p> <p></p> <p>These resources can be used to better understand the history of astronomy, as well as the different ways in which people have used art and science to make observations of the sky. </p> <p></p> <p>keywords: astronomy, astrophysics, Harvard Computers, women in STEM, art, technology, Project PHaEDRA, John G. Wolbach Library, Center for Astrophysics<br><br></p>

<p>Cecilia Payne-Gapsochkin who worked with spectroscopic slides from the Plate Stacks to study the chemical make-up of giant stars, thus discovering that they are made of mainly Hydrogen/Helium and not, as Henry Norris Russell, then the acknowledged "expert" thought, made of the same materials as Earth. Her submitted thesis became the very first in Astronomy at Harvard and, since the then-director of the Physics Department, Theodore Lyman, would not accept such a work from a woman, the Department of Astronomy at Harvard came into being. Despite Norris's original lack of acceptance of Cecilia's findings, the Director of the Yerkes Observatory, Otto Struve, declared the thesis to be "the most brilliant Ph.D. thesis ever written in astronomy."</p> <p><br><br>These online resources include biographies, videos, images, research, and articles. These resources can be used as an introduction into the life of Payne-Gaposchkin and her work. You can even find her entire thesis in these collections. <br><br></p> <p><br><br>keywords: Harvard Computers, astronomy, female astronomers, history of science, women in STEM, Project PHaEDRA, John G. Wolbach Library, Center for Astrophysics<br><br></p>

<p>This collection explores the discoveries and methods of American astronomer Henrietta Swan Leavitt.  She worked at the Harvard College Observatory (HCO) as a “computer”, examining glass photographic plates in order to measure and catalog the brightness of stars. This work led her to discover the relationship between the luminosity (brightness) and the period of brightening/dimming of Cepheid variables (stars that have a distinct brightness and dimming period). Her discovery provided astronomers with the first “standard candle” with which to measure the distance to faraway galaxies and paved the way for modern astronomy's understanding of the structure and size of the universe.  <br><br>Follow the steps throughout the collection to determine the ways that  Leavitt and the other Harvard Computers identified variable stars. In these resources, you'll find images of glass plate photographs that the Computers used for their calculations, as well as videos, quiz questions, and images of Henrietta Leavitt. For more information about Leavitt's life, view the information tab on the first three resources. <br></p> <p></p> <p>For more web resources, check out our other collection: <a href="https://learninglab.si.edu/q/ll-c/qqXikk5s1yijR91U#r/21038">Henrietta Swan Leavitt Web Resources</a>. </p> <p></p> <p></p> <p>Keywords: Harvard Computers, astronomy, female astronomers, history of science, women in STEM, Project PHaEDRA, John G. Wolbach Library, Center for Astrophysics<br></p>