The animation above has 24 frames, and the star is only blocked by one of them. Amanda Zangari, who participated in the observations, told me that this is not the only successful observation, and that it's the shortest chord. In other words, the team got multiple tracks of the star behind MU69, some of which blotted out the star for longer than this observation did. The resulting data that will be superior for constraining the size and shape of MU69 than a single observation would have been.

The observations would not have been possible without the support and assistance of Argentinians. From the team's press release: