Design and fabrication of fold mirror (M3) system for New Robotic Telescope

Ranjbar, Ali; Copley, David; Ghigo, Mauro; Harvey, Éamonn; Steele, Iain A.; Gutiérrez, Carlos M.; Garner, Adam; Bates, Stuart
Referencia bibliográfica

Ground-based and Airborne Telescopes X

Fecha de publicación:
8
2024
Número de autores
8
Número de autores del IAC
1
Número de citas
0
Número de citas referidas
0
Descripción
The New Robotic Telescope (NRT) is an autonomous telescope that can operate multiple instruments at the Cassegrain focal station and the straight-through port. The optical beam is directed to the ports by a fold mirror subsystem in the focal station assembly. The fold mirror is elliptical in shape, manufactured by Instituto Nazionale di Astrofisica (INAF), and polished down to RMS surface deformation of λ/20. An optomechanical analysis is performed to simulate the effect of gravity over the mirror surface deformation and the results have been compared to the interferometry plots to optimize the Ion Beam Figuring (IBF) process to polish the mirror aperture. The mirror assembly is supported by a bipod flexure design to reduce surface deformation under gravity and thermal loads. There are three sets of bipod elements and a central support in the quasi-kinematic support structure. Using wire EDM, the bipods were manufactured precisely as one piece. Following careful preparation and the development of multiple glue jigs to ensure an even glue thickness, the bipods, and central pads are glued to the mirror, and multiple experimental tests have been performed to ensure the glue layer's strength and durability. Other components of the mirror assembly, such as the mirror cell, mirror stand, and moving platform, are being machined out of INVAR, assembled, and mounted on the linear stage and a rotary stage before being installed over the mechanism platform in the A&G box. The design and manufacturing of the mirror assembly, including the gluing process, will be summarised as part of this article.