Open AccessPrototype Development for the GMT FSM Secondary - Off-axis Aspheric Mirror Fabrication -
Author(s) -
Youngsoo Kim,
Jihun Kim,
Je Heon Song,
MyungHaing Cho,
HoSoon Yang,
Joohyung Lee,
Ho-Sang Kim,
Kyoung-Don Lee,
HyoSung Ahn,
Won Hyun Park
Publication year - 2014
Publication title -
journal of astronomy and space sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.273
H-Index - 11
eISSN - 2093-5587
pISSN - 2093-1409
DOI - 10.5140/jass.2014.31.4.341
Subject(s) - polishing , optics , tilt (camera) , figuring , fabrication , materials science , interferometry , surface (topology) , root mean square , physics , mechanical engineering , geometry , mathematics , engineering , medicine , alternative medicine , pathology , quantum mechanics , composite material
A prototype of the GMT FSM has been developed to acquire and to enhance the key technology – mirror fabrication and tiptilt\udactuation. The ellipsoidal off-axis mirror has been designed, analyzed, and fabricated from light-weighting to grinding,\udpolishing, and figuring of the mirror surface. The mirror was tested by using an interferometer together with CGHs, which\udrevealed the surface error of 13.7 nm rms in the diameter of 1030 mm. The SCOTS test was employed to independently\udvalidate the test results. It measured the surface error to be 17.4 nm rms in the diameter of 1010 mm. Both tests show the\udoptical surface of the FSMP mirror within the required value of 20 nm rms surface error