Call for Papers: "The Promise and Pitfalls of Citizen Science," American Philosophical Societ
"Independent" is a reference to institutional affiliation: It is not in contrast to "professional." Citizen scientists is indeed in contrast to professional scientists.
Below is an excerpt from and link to a story entitled "Citizen Scientists Discover Strange New World Pro Astronomers Missed," by Corey S. Powell that appeard on NBC News Mach online on January 11, 2019. I would describe the participants as "independent scientists" given the level of expertise apparently needed to carry out this work.
Semester Programme: (downloadable at https://staticcuris.ku.dk/portal/files/203333747/BBC_Winter_18_19_181003.pdf)
Jan Hansen (Berlin) How to Write an Environmental History of Infrastructure? Water and Power in the Everyday Life of Los Angeles, ca. 1900
Workshop "Science & Dissent", University of Geneva, June 1-2, 2018
Qualification type: PhD
Location: Indianapolis, IN, USA
Funding for: US and International Students
Hours: Full Time
Closes: 15 March 2018