ESO ELT M5 unit: design and manufacturing status

Elise Vernet; Jean-François Pirard; Constanza Araujo Hauck; Pablo Zuluaga Ramirez; Marc Cayrel; Claire Lamour; Jean Louis Carel; Jean Marc Merceron; Solène Doublet; Clément Charuel; David Hartmann; Dominique Bardon; Florent Mallet; Michel Bougoin; Miguel Redondo; Joan Manel Casalta; Ferran Grañena; Jocelyn Refuba; Alexandre Pages; Frank Claeyssen

doi:10.1117/12.2561016

13 December 2020 ESO ELT M5 unit: design and manufacturing status

Elise Vernet, Jean-François Pirard, Constanza Araujo Hauck, Pablo Zuluaga Ramirez, Marc Cayrel, Claire Lamour, Jean Louis Carel, Jean Marc Merceron, Solène Doublet, Clément Charuel, David Hartmann, Dominique Bardon, Florent Mallet, Michel Bougoin, Miguel Redondo, Joan Manel Casalta, Ferran Grañena, Jocelyn Refuba, Alexandre Pages, Frank Claeyssen

Author Affiliations +

Proceedings Volume 11445, Ground-based and Airborne Telescopes VIII; 114453O (2020) https://doi.org/10.1117/12.2561016
Event: SPIE Astronomical Telescopes + Instrumentation, 2020, Online Only

Abstract

The ELT is a project led by the European Southern Observatory (ESO) for a 40-m class optical, near- and mid-infrared, ground-based telescope. When it will enter into operation, the ESO ELT will be the largest and most powerful optical telescope ever built. It will not only offer unrivalled light collecting power, but also exceedingly sharp images, thanks to its ability to compensate for the adverse effect of atmospheric turbulence on image sharpness. The basic optical solution for the ESO ELT is a folded three-mirror anastigmat, using a 39-m segmented primary mirror (M1), a 4-m convex secondary mirror (M2), and a 4-m concave tertiary mirror (M3), all active. Folding is provided by two additional flat mirrors sending the beams to either Nasmyth foci along the elevation axis of the telescope. The folding arrangement (flat M4 and M5 mirrors) is conceived to provide conveniently located flat surfaces for an adaptive shell (M4) and field stabilization (M5). The M5 Mirror and M5 Cell contracts started in 2019. Both sub-units are currently designed by the selected contractors. While the cell is still in an early design phase, the mirror design is in the final phase and the manufacturing of the blank has already started. With the focus on the M5 mirror, we flow down the key requirements to the cell and the mirror and highlight the main characteristics of the current design, discussing the challenges of mirror manufacturing. Finally, we conclude with the current status and an overview of the coming milestones.

Conference Presentation

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Elise Vernet, Jean-François Pirard, Constanza Araujo Hauck, Pablo Zuluaga Ramirez, Marc Cayrel, Claire Lamour, Jean Louis Carel, Jean Marc Merceron, Solène Doublet, Clément Charuel, David Hartmann, Dominique Bardon, Florent Mallet, Michel Bougoin, Miguel Redondo, Joan Manel Casalta, Ferran Grañena, Jocelyn Refuba, Alexandre Pages, and Frank Claeyssen "ESO ELT M5 unit: design and manufacturing status", Proc. SPIE 11445, Ground-based and Airborne Telescopes VIII, 114453O (13 December 2020); https://doi.org/10.1117/12.2561016

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