The Bulletin of The Korean Astronomical Society (천문학회보)
- Volume 37 Issue 2
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- Pages.219.2-219.2
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- 2012
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- 1226-2692(pISSN)
The Tip-Tilt Correction System in AO System for Small Telescope
- Yu, Hyungjun (Astronomy Program, Dept of Physics & Astronomy, Seoul National University) ;
- Park, Yong-Sun (Astronomy Program, Dept of Physics & Astronomy, Seoul National University) ;
- Lee, Bangweon (Astronomy Program, Dept of Physics & Astronomy, Seoul National University)
- Published : 2012.10.17
Abstract
We are developing Adaptive Optics (AO) system for 24 inch telescope at Seoul National University Observatory. It consists of the tip-tilt correction system and the residual wavefront error correction system with a deformable mirror and a wavefront sensor. We present the construction and performance measurements of the tip-tilt correction system. The tip-tilt component is the single largest contributor to wavefront error, especially for small telescope. The tip-tilt correction system consists of a quadrant photodiode, a tip-tilt mirror and a feed back loop. The collimated He-Ne laser beam is used for input light source and is artificially disturbed by air turbulence generated by a heat gun. Most of the turbulence is of low frequency less than 20 Hz, but extends to a few hundreds Hz. It is found that the closed loop system using proportional-integral-derivative (PID) control successfully corrects tip-tilt error at a rate as high as 300~400 Hz.
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