PHARO Instrument Design

Cutaway drawings of PHARO. The upper vacuum shell, upper radiation shield, and several covers and light baffles are omitted for clarity.

Overhead view of worksurface in 25 mas/pixel imaging mode

PHARO Images. Click on any of the small images to view its full size version.

This is the PHARO dewar on its handling cart. Inside the aluminum outer shell is the main workplate on which the optics and detector are mounted, and a system of liquid nitrogen tanks and radiation shields that keep these components cooled to 77 Kelvin. The necks for the tanks, the vacuum pump-out valve, and other ports can be seen extending from the bottom of the dewar. Light enters through the window on the right end of the dewar (covered in this view), and the dewar is mounted on the telescope via three stainless steel pins, one of which is visible on the front face of the dewar.

A side view of the opened instrument showing the optics, filter and slit wheels, cryogenic stepper motors, and detector housing. The system of light baffles has not yet been installed.

An end view showing the slit wheel on the left and the detector housing on the right. Near the back of the dewar two gold-coated OAP mirrors can be seen.

The 1024x1024 pixel HgCdTe HAWAII detector mounted on its fan-out board.

PHARO mounted on the JPL Adaptive Optics System optical bench at Palomar. The Adaptive Optics are enclosed by the black cover. Mounted on the PHARO dewar are the detector and stepper motor electronics boxes.

A view from directly underneath the 200-inch telescope, looking up at the AO System and PHARO mounted at the f/16 Cassegrain focus. The doors of the AO system's protective cover are open, exposing the internal optics. The wavefront sensor assembly is visible at the bottom of the opening; the two off-axis paraboloid (OAP) mirrors are housed in the blue mounts at upper right, and the 349-element deformable mirror is the black box just below the OAP's.