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1 m 2 mirror technology. AIM find a suitable technology for large reflecting surface reduce the overall cost with respect the current tecnology Improve or maintain the actual optical quality Avoid the use of panels for Active Mirror Controls Develop technologies for very large reflectors.
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1 m2 mirror technology • AIM • find a suitable technology for large reflecting surface • reduce the overall cost with respect the current tecnology • Improve or maintain the actual optical quality • Avoid the use of panels for Active Mirror Controls • Develop technologies for very large reflectors
Front plate Honeycomb sandwich Magic I technology: pre-milling
Panel assembling in Eching Adjustment legs screwed on the mirror Cabling of the mirror for internal heater 2 mirrors mounted on a panel
Pre-alignment of a mirror in a panel A panel in the alignment tripod
Alignment tools Artificial parallel beam source Rotating tripod for panel alignment
Final alignment Final spot of a panel after The precise alignment of the mirrors 4 mirrors spots after the pre-alignment close to the virtual center of the MAGIC camera
1 m mirror Large single mirror vs 4 small mirrors in a panel 50 cm mirrors • 4 mirrors: • better optics • more labor + expensive panel needed • hand made first aligment (+?) • many high tech elementsto build a panel • Diamond turning prooven technology • Single large mirror: • Astigmatism important at large radii • Self supporting ->no panel needed • No manual alignment necessary • Big labor for the premilling • Diamond turning OK AMC motors
Ongoing R&D in Padova • Built 1m mirror with native spheric shape • aluminum sandwich glued on a spheric mould Front plate Mirror box + honeycomb mould
Ongoing R&D in Padova • Built 1m mirror with native spheric shape • aluminum sandwich glued on a spheric mould
Ongoing R&D in Padova 6 Prototype produced in 2005: Light weight : <18 Kg, to be installed in the telescope without any support panel.
Diamond milling first round • - Good reflectivity • Bad sphere ~ donuts: • Error in the alignment of • Diamond tool
Diamond milling second round Almost a perfect sphere. The rigidity of the new mirrors and the tune-up of the milling machine are now delivering very good results: The technique is becoming reliable
Impact of 1m2 in the reflector optical quality Full simulation is needed: modification of reflector program. hybrid combination: rings with small mirrors combined with rings with large mirrors (Denis & Michele) Option of 2 radii of curvature for outer rings: -technique to be proven but promising -need 60 Keuro of investments drawbacks -> not easy task to measure and check the optical quality. -> each mirror will become “unique” in the reflector
Production costs • Raw blank: • Pre-production • Production (1+/day in pipeline)