Lessons for the Scientist-Communicator: Education \& Public Outreach in The Dark Energy Survey

The Dark Energy Survey (DES) Collaboration is an international astronomy collaboration of 400 scientists (graduate student to professor) from $\sim$ 30 institutions. Our education and public outreach (EPO) program is a unique, grass-roots effort that sets new standards for large science collaborations. We describe several in-person and online initiatives in which scientists develop connections with local communities and reach global audiences. We also present some of the organizational and logistical challenges of our EPO experience and the lessons learned that will be invaluable for future large-scale projects.