When did the astros last play in the world series?
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When did the Astros play in the World Series for the first time?
October 22–26, 2005
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When did the Astros play in the World Series for the second time?
October 24 – November 1, 2017
Houston Astros
https://en.wikipedia.org/wiki/Houston%20Astros
The Houston Astros are an American professional baseball team based in Houston.
Houston Astros
The Astros faced the Chicago White Sox in the World Series. Chicago had been considered the slight favorite but would win all four games, the first two at U.S. Cellular Field in Chicago and the final two in Houston. 
Houston Astros 2005: First World Series played in Texas
The Astros won the ALCS four games to three, and advanced to the World Series to play against the Los Angeles Dodgers. The Astros defeated the Dodgers in the deciding seventh game of the World Series, winning the first championship in franchise history.[81]
Houston Astros 2015–present: First World Series title and sign stealing scandal
The Houston Astros are an American professional baseball team based in Houston. The first time they played during the World Series was World Series 2005, from October 22–26, 2005, where they faced the Chicago White Sox and lost all four games. The second time they appeared was during World Series 2017, from October 24 – November 1, 2017. There they would defeat the Los Angeles Dodgers, winning the first championship in franchise history.