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He then worked at the Harvard-Smithsonian Center for Astrophysics in Cambridge , Massachusetts .
 Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts