The twin Keck telescopes will initially form a two-element interferometer with a separation of 85 meters. With the light-gathering capability of the two 10-m telescopes, the resulting interferometer will give the angular resolution of an 85-meter telescope: 8.5 times that of a single Keck telescope.
A view of the Keck 2 primary mirror, made up of 36 1.8m hexagonal mirror segments. The conical tube in the center of the mirror is a baffle, below which is reflected an image of the round secondary mirror. To the right is a white enclosure that houses the adaptive optics system for Keck 2.
- Adaptive Optics System: This is a system that removes the distortion in starlight caused by the Earth's atmosphere. A sensor is used to measure the distortion, which is corrected by a many-element deformable mirror at the rate of about 500 times a second. Animation: QuickTime (5.5 MB) Real Player (548 KB)
- Dual-Star Module: This instrument directs incoming light from two adjacent stars that each telescope of the interferometer will be looking at to different beam trains in the interferometer. One star is used as a reference star, while the other will typically be a more distant "science" star.
- Coude Train and Beam Transport: This system brings light from the Keck Telescope into the basement laboratory where the beams of light are combined.
- Delay Lines and Metrology: The delay lines equalize the pathlengths of the light collected by each telescope -- except for stars directly overhead, the starlight will arrive at one telescope before the other. A metrology system measures the pathlengths along the light paths.
- Fringe-tracker: This instrument measures the interference of the light from a star collected by each of the two telescopes and adjusts the optical delay lines to keep the light from each telescope in sync.
- Angle-tracker: This instrument corrects for small tilts in the beams of light from each telescope so that all beams overlap when light is combined in the fringe tracker.
- Nulling Combiner: This instrument nulls, or cancels, the light from a star so that the faint dust surrounding the star can be observed.
- Control System: All of the subsystems of the Keck Interferometer are controlled by computers that read in data from cameras and other sensors, adjust motors and other actuators, record data for scientists to use, and provide a user interface from which to operate the interferometer.
