CELT

The University of California is studying concepts for the next generation of large telescopes, and has proposed that the Keck-style segmented design be applied to a 30 meter diameter telescope.  The CELT (California Extremely Large Telescope) is a design concept for the next generation of very large optical/infrared telescopes. The CELT telescope can be summarized as:

Status:

• 30-m diameter primary mirror optical/infrared telescope
• 1000-segmented mirror design with active control of the  hyperbolic surface figure
• 3 x 1000 actuators on the primary mirror (tip, tilt & piston)
• ~ 100 nm optical wavefront error budget
• 4-m diameter (convex) secondary mirror

• Segment fabrication and testing (industrial scale of  precision optics)
• Support of the mirror surface (few grams of Al)
• Precision positioning of mirror segments with long term stability
• Dynamic response of the structure to (turbulent)  wind loading (CFD problem)
• Consider for primary and secondary mirrors
• Adaptive optics control of atmospheric wavefront aberrations
• 20,000 actuators, 40,000 wavefront measurements
• FFT, conjugate gradient & preconditioners
• Physical plant
• Enclosure & dome
• Site selection
• Long term site testing to find good transparency,  low water vapor and good seeing
• Computational fluid dynamics (CFD) problem: response of laminar flow to topography,   enclosure and telescope structure
• Climate modeling to understand long term viability of the site