Optical Telescope Metrology Fixture
Thirty Meter Telescope Laser Tracker Metrology Fixture
Scientific research. Ground-based radio telescope.
Previous Limiting Technology
The high precision, low weight, high stiffness and low CTE requirements of these reflector alignment fixtures would normally require a prohibitively expensive solution.
The Thirty Meter Telescope (TMT) requires precision fixtures to align the 492 hexagonal mirror segments that make up the massive 30-meter primary mirror array. Ten fixtures are required to complete the reflector alignment. In addition to high precision and low CTE requirements, aggressive cost containment measures were necessary to meet program budget.
Rock West used off-the-shelf carbon fiber plate and our ZTETM (zero coefficient of thermal expansion) Carbon Tubes to engineer an elegant and extremely cost-effective solution. We utilized low cost assembly fixtures using off-the-shelf ground plates trimmed by waterjet and off-the-shelf precision positioning towers. We also used environmentally-friendly etch and prime technology for the invar fittings. Tolerances were kept within +/-0.0015” and positional stability was maintained at less than 0.0001” over a 10°C change in temperature.