CCAT-prime (or CCAT-p, for Cerro Chajnantor Atacama Telescope, prime) is a 6 meter telescope in development for deployment on the 5600m Cerro Chajnantor peak on the Atacama Desert, Chile. It is designed for surveys, with a large field of view, in the far-infrared/microwave range, aiming to survey the Sunyaev-Zel'dovich effect, intensity mapping of the redshifted [CII], and to take advantage of its capabilities for other science.
The high, desert site is ideal for millimeter astronomy, offering many clear days/nights for observation and minimal moisture, thus minimizing absorption from water lines. Frequent night-time temperature inversions below the level of the telescope result in even drier air for observation.
It has a large, flat focal plane. The telescope mirrors' housing is attached so the housing turns and tilts (elevates) with the mirrors, and the elevation range spans 180°, i.e., the aim can flip across the zenith. The intended scanning is horizontal, so each entire sweep experiences analogous atmospheric effects. Planned instruments:
Prime-Cam (aka P-Cam) has a modular design, allowing seven instruments to be installed, next to each other in the focal plane. They all share the Prime-Cam cryogenic cooling (aiming at 0.1 K for low thermal noise), and initially, three of the bays will be filled:
An alternate optical path allows non-Prime-Cam instruments to be installed. Initially, that will be CHAI (a heterodyne array spectrometer) but there is space for more.
Other instruments have been cited during planning, including P-Spec (imaging spectrometer) and P-CMBcam (CMB camera). These may be modules for Prime-Cam.
Off-site telescope construction is underway, aiming for first light in 2021. The project is the outgrowth of the larger (25m) CCAT proposal.