WFC3 Commissioning

John W. MacKenty,

After eleven years of design, development, testing, launch delays, modifications, and more testing, Wide Field Camera 3 (WFC3) was launched on space shuttle STS-125 on May 11, 2009. After a heart-stopping moment when the Wide Field Planetary Camera 2 was reluctant to leave the radial bay of Hubble, installation of WFC3 proceeded smoothly. The instrument passed all of its engineering checkout activities and, after 21 days of waiting for the detector packages to fully outgas, the detectors were successfully cooled to their planned operating temperatures on June 11. Testing, optical alignment, and initial calibration followed (briefly interrupted by a few images of an impact event on Jupiter) with WFC3 performing as well as or better than expected.

Key findings about WFC3 from the commissioning process include (1) the throughput of both channels range from 5 to 15 percent above prelaunch predictions, (2) the near-infrared channel can indeed continue operating inside the South Atlantic Anomaly, and (3) the detector noise levels are as expected from ground testing. As of mid-September, WFC3 is actively conducting science observations and beginning its Cycle 17 calibration program.

Observers and proposers are referred to the “Late Breaking News” section of the Institute website.

F140W, Stephan's Quartet

F140W, Stephan's Quintet