Prize

•   2003 Education Prize of the American Astronomical Society
•  2017 Richtmyer Memorial Lecture Award of the American Association of Physics Teachers

Honorary Membership

•   Royal Astronomical Society of Canada, 2003

Officer and Committee Member

•   2011-13 Vice-Chair, Historical Astronomy Division, American Astronomical Society; 2013-15, Chair.
•   U.S. National Representative to Commission 46 (The Teaching of Astronomy) of the International Astronomical Union (1979–2000)
•   American Association for the Advancement of Science (Chairperson-elect, Section D—Astronomy, 1986–87, Chairperson, 1987–1988, Retiring Chairperson, 1988–1989); 1996-1997, Chair-Elect, 1997–1998, Chair, 1998–-1999, Retiring Chair; representative to the AAAS from the AAS, 2004-07, 2008-2010, 2010-2013, 2013-2016, 2017-2020; elected member of Electorate Nominating Committee, 2010-2013.
•   American Association of Physics Teachers (Astronomy Education Committee, 1983–1987)
•   American Astronomical Society, Astronomy Education Advisory Committee (1990–1997); Astronomy News Committee (1991–1996); Working Group on Astronomy Education Organizing Committee, 1991–1997)
•   NASA Astrophysics Council (1990–1992)
•   I.A.U. Representative to the International Council of Scientific Unions–Committee on Teaching of Science, 1991–1994
•   American Physical Society (AAPT/APS Member-at-large, Forum on Education, 1995–1997)
•   U.S. National Liaison to Commission 46 (Astronomy Education and Development) of the I.A.U. (2000–); Vice-President, 2000–2003, President, 2003–2006

Member

•   International Astronomical Union
•   American Astronomical Society
•   American Physical Society (Fellow, 1987–)
•   Royal Astronomical Society (Fellow)
•   New York Academy of Sciences (Fellow)
•   Sigma Xi (President, Williams College Club, 1973–74,1996–)
•   International Planetarium Society (Fellow, 1992–)
•   Astronomical Society of the Pacific
•   International Union of Radio Science (URSI) Commission on Radio and Radar Astronomy
•   American Association for the Advancement of Science (Fellow, 1984–)
•   American Association of Physics Teachers
•   Committee on Scientific Inquiry (Fellow, 2010—)

International Astronomical Union General Assemblies Attended

•   Hamburg 1964
•   Prague 1967
•   Brighton 1970
•   Sydney 1973
•   Grenoble 1976
•   Montreal 1979
•   Patras 1982
•   Baltimore 1988
•   Buenos Aires 1991
•   The Hague 1994
•   Kyoto 1997
•   Manchester 2000
•   Sydney 2003
•   Prague 2006
•   Rio de Janeiro 2009
•   Beijing 2012
•   Honolulu 2015
•   Vienna (planned) 2018

I.A.U. Commissions

President, Commission 46 (Astronomy Education and Development) of the International Astronomical Union (2003-2006); Retiring President (2003-2006); U.S. National Liaison to the Commission (now C.C1 Astronomy Education and Development) and its predecessor, The Teaching of Astronomy, (1976–2015); https://www.iau.org/science/scientific_bodies/commissions/C1/members/

Education Advisory Boards

•   American Association of Variable Star Observers (NSF Curriculum Grant)
•   Hands-On Astrophysics
•   Astronomical Society of the Pacific (NSF Curriculum Grant)
•   Project ASTRO American Astronomical Society project (NSF Curriculum Grant)
•   American Astronomical Society Teacher Resource Agents
•   AASTRA Odyssey, a children’s magazine (Cobblestone Publishing)
•   World Book Encyclopedia
•   Griffith Observatory “Depths of Space” Advisory Board, 2001–2006
•   Astronomy Education Review (National Optical Astronomy Observatories), Council of Advisors, 2002–2012
•   McGraw-Hill Encyclopedia of Science and Technology and yearbooks, 1983–

Research at l’Institut d’Astrophysique, Paris, Observatoire de Paris

•   Summers 1962, 1964, 1967, January 1973, summer 1976, fall 1988