On July 25 2011，Appraisal of Φ500mm UV collimator developed by NIAOT has been passed through at Xi’an。

Φ500mm UV collimator is a non-centre obstruction total reflection system with large aperture,fast focal ratio and wide field view, which is very strct with design, manufacturea,test and adjustment。It took ten month for NIAOT to complete the project。

Testing result on site indicate that every qualification achieved and exceeded specification requirement。RMS results of wavefront deviation were superior to λ/25 in Φ500 effective aperature and ±0.172° field view。

During which，0 field view RMS was λ/34, 0.5 field view RMS was λ/30, 0.7 field view RMS was λ/28。（λ=632.8nm）

UV collimator in the overall structure and overall performance have achieved a breakthrough. The project has accumulated a wealth of practical experience for high-precision large-diameter off-axis optical system development and large-diameter off-axis aspheric manufacture and test。