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A control loop closure system for the Sardinia Radio Telescope active surface
C. Pernechele, Coordinator C. Barbieri, CMOS camera P. Bolli, mw holography F. Buffa, photogrammetry T. Pisanu, FEM, temperature sensor S. Poppi, pointing, star tracker G. Serra, mw holography M. Morsiani, mounts & test J. Roda, mechanics G. Zacchiroli, mechanics C. Nocita, test M. Paternò test INAF Astronomical Observatory of Cagliari & National Institute for radioastronomy Sept, 27th 2016
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EL 64 m AZ 70 m Weigth 3000 Tons General parameters Note
Sept, 27th 2016
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Gregorian Optical Configuration
Note F1/D = > GHz FG/D = > GHz F3/D = > GHz F4/D = > GHz Sept, 27th 2016
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Metrology Tasks Note Sept, 27th 2016
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Star tracker (Poppi et al.,
Metrology Tasks PSD + rangefinder (5 axes) Star tracker (Poppi et al., (SPIE 7733, 2010) Note FEM + temp sensors (Pisanu et al., SPIE 7739, 2010) Optical methods (reflector’s shape) Sept, 27th 2016
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Photogrammetry results @ Noto station SARDINIA RADIO TELESCOPE
Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
100 GHz Surface shape < 0.15 mm (l/20) Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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Radio vs Visible Active Optics SARDINIA RADIO TELESCOPE
Visible Range Closed loop control Radio Range Open loop only Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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Shape’s main reflector typical measurements systems
Primary’s shape measuring methods Shape’s main reflector typical measurements systems Time response Accuracy Meas. type EL Angle Laser Scanner Hours/day 0.7 mm Absolute Any Photogrammetry day(s) 0.4 mm Microwave Holography Hours 0.15 mm <45 for SRT SRT optical meas. systems Few minutes Relative Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SRT actuators closing loop strategy SARDINIA RADIO TELESCOPE
Note OOF Holography planned in collaboration with GBT (R. Prestage) SARDINIA RADIO TELESCOPE Sept, 27th 2016
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General considerations SARDINIA RADIO TELESCOPE
Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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The three tested systems SARDINIA RADIO TELESCOPE
Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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General considerations
Note SARDINIA RADIO TELESCOPE SARDINIA RADIO TELESCOPE
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SARDINIA RADIO TELESCOPE
Segmented Profiles Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
Segmented Profiles Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
Segmented Profiles Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
Segmented Profiles Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
Hartmann like Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
Hartmann like Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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SARDINIA RADIO TELESCOPE
Hartmann like Error bar +/- 70 μm Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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Scanning Position System SARDINIA RADIO TELESCOPE
Note SARDINIA RADIO TELESCOPE Sept, 27th 2016
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Comparison among the three systems
& Conclusions Note Sept, 27th 2016
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