by Jim Fanson, Kepler, JPL Project Manager
Mission Manager Update
Engineers are continuing the process of calibrating Kepler's photometer in the dark, with its dust cover on. Because the instrument's charge-coupled device (CCD) focal plane (the area where light from the telescope will be focused) is so large, it does not have a built in shutter to keep light out. Kepler's focal plane is one square-foot, while the focal plane in your digital camera is the size of a fingernail.
Dark calibration data are being taken at various sun angles, the first three of which are now complete. The forth attitude is designed to provide the darkest background and will point the telescope as far away from the sun as possible while maintaining enough sunlight on the solar panels to power Kepler's electrical systems. Once these data are analyzed and the calibration products are complete, a series of reviews will be convened to obtain approval to release the cover, which will separate from the spacecraft and follow its own orbit around the sun.