Mentorship and Legacy

Mentoring the Observatory Staff

AJC photo of llama herd in Peru

Annie Cannon mentored the observatory staff in both style and substance. Set in relief to her astronomical work ethic, her joyous outlook uplifted her colleagues; whether by sharing a snapshot of crowding llamas in Arequipa (Fig. 10 -- photography was a favorite hobby of hers), or by hosting proper tea services for society and discussion (Fig. 11). These events also attracted guests and visits scientists, whose fresh perspectives enriched the observatory, such as when Albert Einstein visited in 1935 (Fig. 12). Beyond the observatory, Cannon's activities called for a better world: she was a suffragist, a member of the National Women’s Party, and represented professional women at the World’s Fair in Chicago in 1933.

AJC teapotAJC Guestbook with Dr. Albert Einstein's name

Modern Astronomy

Sloan Digital Sky Survey logo

SDSS telescope

SDSS IV instrument

Cannon's legacy of spectral classification lives on with the the fourth phase of the Sloan Digital Sky Survey (SDSS-IV, Fig 13, 14, 15). This project started in September 2014, and is planned to continue to the year 2020. It has three components:
  1. eBOSS, an emission-line and luminous-red galaxy and quasar redshift survey to study baryon oscillations (BAO).
  2. MaNGA, a spatially-resolved integral field unit (IFU) spectral survey of 10,000 nearby galaxies.
  3. APOGEE2, an extension of the APOGEE survey to much more of the sky, including the Southern hemisphere using the Las Campanas Observatory in Chile.

It also includes a software suite titled "The Cannon," named after our subject because it can classify many spectra quickly, using a small set of anchors, shown as large dots -- the graph below displays a virtually automatic classification of approximately 35,000 stars (Fig. 16). And while Cannon tabulated and published her work in paper tomes, the SDSS and other modern classification projects will live in digital repository platform such as The MaStar MaNGA Stellar Library, which will hold over 10,000 spectra (Fig. 17).

Results of The Cannon automatic star classification

MaStar MaNGA Stellar Library program

Image Sources

10. Cannon, A. (1863). Llamas [Photograph]. Papers of Annie Jump Cannon, 1863-1978, Harvard University Archives, Cambridge, MA.

11. McEachern, M. (2018). Photograph of Annie Cannon’s tea set [Image]. Cambridge, MA: John J. Wolbach Library. 

12. Cannon, A. (1912). Guest book. Project PHaEDRA, Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA.

13. Sloan Digital Sky Survey. SDSS logo [Image]. Retrieved from

14. Adapted from Figure 2 from “The 2.5 m Telescope of the Sloan Digital Sky Survey,” by J. Gunn et al., 2006, The Astronomical Journal, 131, p. 2333. Copyright 2006 by The American Astronomical Society. 

15. Berry, D., SkyWorks Digital Inc., Law, D. & Sloan Digital Sky Survey. (n.d.). SDSS IV [Image]. Retrieved from 

16. Adapted from Figure 10 from “The Cannon: A data-driven approach to stellar label determination” by M. Ness et al., 2015, The Astronomical Journal, 808(16), p. 15. Copyright 2015 by The American Astronomical Society. 

17. Yan, R. et al. (2018). Example spectra from MaStar Library [Image]. Retrieved from