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Dispersed fringe sensor for the Giant Magellan Telescope
Applied Optics
|February 3, 2016
Summary
The Giant Magellan Telescope (GMT) uses a novel dispersed fringe sensor (DFS) to measure segment piston. This method achieves 50 nm accuracy, enabling precise optical phasing for enhanced astronomical observations.
Area of Science:
- Astronomy and Astrophysics
- Optical Engineering
Background:
- The Giant Magellan Telescope (GMT) features seven 8.365 m segments with 0.345 m gaps.
- Phasing these segments, specifically measuring segment piston optically during science operations, presents a significant challenge.
Purpose of the Study:
- To present a novel dispersed fringe sensor (DFS) and algorithm for measuring segment piston in the GMT.
- To demonstrate the feasibility of achieving high-accuracy segment piston measurements in real-time.
Main Methods:
- Utilized four off-axis dispersed fringe sensors (DFS).
- Operated the DFS in the J-band with 10 ms exposure times.
- Developed and applied a novel algorithm for piston measurement.
Main Results:
- Achieved segment piston measurement accuracy of 50 nm.
- Enabled measurements every 30 seconds.
- Demonstrated over 90% sky coverage for the measurement system.
Conclusions:
- The proposed DFS system effectively measures segment piston with the required accuracy.
- This technology is crucial for phasing the GMT segments during science operations.
- The system offers a practical solution for real-time optical alignment in large segmented telescopes.
