Characterizing the vibration environments of the Gemini telescopes

We report the results of a multi-year program to measure the vibration characteristics of the two Gemini telescopes. Measurements with fast-guiding wavefront sensors and networks of accelerometers show a correlation between image motion and optical vibrations induced mostly by instrument cryocoolers. We have mitigated the strongest vibrations by fast-guiding compensation and active cancellation of vibration sources.