Directly polished lightweight aluminum mirror

Rik ter Horst; Niels Tromp; Menno de Haan; Ramon Navarro; Lars Venema; Johan Pragt

doi:10.1117/12.788657

23 July 2008 Directly polished lightweight aluminum mirror

Rik ter Horst, Niels Tromp, Menno de Haan, Ramon Navarro, Lars Venema, Johan Pragt

Proceedings Volume 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation; 701808 (2008) https://doi.org/10.1117/12.788657
Event: SPIE Astronomical Telescopes + Instrumentation, 2008, Marseille, France

Abstract

During the last ten years, Astron has been a major contractor for the design and manufacturing of astronomical instruments for Space- and Earth based observatories, such as VISIR, MIDI, SPIFFI, X-Shooter and MIRI. The collaboration between optical- and mechanical designers at Astron led to new design philosophies and strategies. Driven by the need to reduce the weight of optically ultra-stiff structures, two promising techniques have been developed in the last years: ASTRON Extreme Lightweighting for mechanical structures and an improved Polishing Technique for Aluminum Mirrors. Using one single material for both optical components and mechanical structure simplifies the design of a cryogenic instrument significantly, it is very beneficial during instrument test and verification, and makes the instrument insensitive to temperature changes. Aluminum has been the main material used for cryogenic optical instruments, and optical aluminum mirrors are generally diamond turned. The application of a polishable hard top coating like nickel removes excess stray light caused by the groove pattern, but limits the degree of lightweighting of the mirrors due to the bi-metal effect. By directly polishing the aluminum mirror surface, the recent developments at Astron allow for using a non-exotic material for light weighted yet accurate optical mirrors, with a lower surface roughness (~1nm RMS), higher surface accuracy and reduced light scattering. This paper presents the techniques, obtained results and a global comparison with alternative lightweight mirror solutions.

Citation Download Citation

Rik ter Horst, Niels Tromp, Menno de Haan, Ramon Navarro, Lars Venema, and Johan Pragt "Directly polished lightweight aluminum mirror", Proc. SPIE 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 701808 (23 July 2008); https://doi.org/10.1117/12.788657

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available