[1] In 1907, William Cameron Sproul communicated to the Board of Managers of Swarthmore College his desire to donate funds for the purchase of equipment for an astronomical observatory.

[6] In 2009, Swarthmore College added the Peter van de Kamp Observatory to the newly built Science Center.

[5] In 2017, the telescope was dismantled and moved to the Eighth Street Market in Bentonville, Arkansas to be restored, upgraded and used for public outreach.

[1] The book collection of the Sproul Observatory was donated to an astronomy center in Magdalena, New Mexico.

These plates were found to have a systematic error that was misinterpreted as the effect of a planetary system on the parent star.