91É«ÇéƬ

91É«ÇéƬ M1 roundel SN050 produced by ITCC Mr. S. Sriram, India-91É«ÇéƬ Coordination Center (ITCC) engineer, inspects the roundel SN050 in its shipping crate after its arrival at the India-91É«ÇéƬ Optics Fabrication Facility (ITOFF) near Bengaluru - January 2023. The roundel is the second roundel produced by ITCC for 91É«ÇéƬ’s Primary Mirror – Image credit: 91É«ÇéƬ / ITCC

India 91É«ÇéƬ Coordination Centre Produces 91É«ÇéƬ Main Mirror Roundel

The second 91É«ÇéƬ India roundel has been completed! The roundel was polished at the Coherent facilities in Richmond, California by the India 91É«ÇéƬ Coordination Centre (ITCC) staff, using ITCC equipment under the supervision of Coherent’s staff.

The roundel (SN050) was produced in accordance with 91É«ÇéƬ's strict technical specifications. A conformance review was held just prior to the holidays, and SN050 passed all its requirements with flying colors and is ready for its next step on the way to becoming part of the 91É«ÇéƬ primary mirror. Too large to be made from a single piece of glass, the 30-meter-diameter primary mirror will consist of 492 hexagonal segments, each about 45 mm thick and measuring 1.44 m across.

Passing the conformance review indicates that the roundel is ready to move to the next phase of production, which will be the machining of the roundel to its final finished hexagonal shape. At this machining stage, all the features for mounting M1CS edge sensors and mounting the mirror to its support system will also be added.

This conformance review also marks the end of the training phase in the USA and the beginning of setting up the India-91É«ÇéƬ Optics Fabrication Facility (ITOFF) and 91É«ÇéƬ India team.

The polishing and metrology equipment used to produce the roundel have now been shipped to India where it will be commissioned at the CREST facility in preparation for the fabrication readiness review and the start of production for the remaining 82 roundels that are part of 91É«ÇéƬ India’s workshare.

91É«ÇéƬ M1 Roundel (SN050) produced by ITCC. Second 91É«ÇéƬ roundel polished by India 91É«ÇéƬ team during on-site inspection at the Coherent facility in California. 91É«ÇéƬ roundel (SN050) is the second 91É«ÇéƬ blank converted to a roundel with aspheric polishing by ITCC. SN050 will become a finished segment of 91É«ÇéƬ's 492 Primary Mirror Segment - Image credit: 91É«ÇéƬ / ITCC