Ultra low thermal expansion material for telescope mirror substrate

Kousuke Nakajima; Nobuo Kawasaki; Toshihide Nakajima; Yoshiyuki Owari; Hiroyuki Minamikawa

doi:10.1117/12.670896

6 July 2006 Ultra low thermal expansion material for telescope mirror substrate

Kousuke Nakajima, Nobuo Kawasaki, Toshihide Nakajima, Yoshiyuki Owari, Hiroyuki Minamikawa

Proceedings Volume 6273, Optomechanical Technologies for Astronomy; 62732M (2006) https://doi.org/10.1117/12.670896
Event: SPIE Astronomical Telescopes + Instrumentation, 2006, Orlando, Florida , United States

Abstract

The material property of CLEARCERAM^®-Z series, which is the low thermal expansion glass-ceramics products by Ohara Inc., with an integrated product size of Dia.1.4meter was investigated along with confirmation of the surface finish performances. The material property investigation for the Dia.1.4meter CLEARCERAM^®-Z HS indicated the mean CTE of 0.01×10^-7/degree C, the CTE uniformity (CTEmax.-CTEmin.) of 0.10×10^-7/degree C based on developed precision CTE measurement system with 2ppb/degree C repeatability and the maximum stress birefringence of 4.4nm/cm within the disk, which are meeting the mirror substrate material specification for near future large telescope project (Thirty Meter Telescope project). From the experiments to determine surface finish performance, no practical change was observed for the surface profile in millimeter scan filed per Ion Beam Figuring processing. Also the surface robustness against acid solutions, which are used at mirror cleaning, was proved from dipping tests using Hydrochloric acid and Nitric acid. With the material property based on the precision metrology and the surface finish performances, the suitability of CLEARCERAM^®-Z for telescope mirror substrate application was presented.

Citation Download Citation

Kousuke Nakajima, Nobuo Kawasaki, Toshihide Nakajima, Yoshiyuki Owari, and Hiroyuki Minamikawa "Ultra low thermal expansion material for telescope mirror substrate", Proc. SPIE 6273, Optomechanical Technologies for Astronomy, 62732M (6 July 2006); https://doi.org/10.1117/12.670896

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

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
10 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Surface finishing

Mirrors

Telescopes

Polishing

Birefringence

Refractive index

Ion beams

Show All Keywords

Keywords/Phrases

Search In:

Publication Years