Observatory Employs New Process in Gemini Mirrors

AlumiPlate Inc. of Minneapolis, in collaboration with the National Optical Astronomy Observatory and II-VI Inc. of Saxonburg, Pa., has developed a diamond-turning process that yields the high-quality mirrors necessary for the near-IR spectrograph in the Gemini 8-m telescope project.

In producing high-surface-quality metal mirrors, engineers typically use electroless nickel to plate the mirrors, but bending of the mirror surface can occur when the temperature changes. AlumiPlate says that the new diamond-turning process decreases the risk of thermally induced distortions, while also reducing the chance of surface pitting or breakage of diamond-cutting tools.
A nonprofit consortium of 27 US institutions and four international affiliates manages the Gemini project. The observatory is headquartered at the University of Hawaii in Hilo.