Negative thermal expansion ALLVAR alloys for telescopes

  title={Negative thermal expansion ALLVAR alloys for telescopes},
  author={James A. Monroe and Jeremy S. McAllister and David S. Content and Jay Zgarba and Xavier Huerta and Ibrahim Karaman},
  booktitle={Astronomical Telescopes + Instrumentation},
Most materials naturally expand when heated and contract when cooled; this is known as thermal expansion and is typically characterized by a Coefficient of Thermal Expansion (CTE). Competition between different materials, each with their own CTE, can push optic systems out of focus when the system’s temperature changes. The use of low CTE materials like Invar, carbon fiber composites, and silicon carbide help reduce these temperature effects. Unfortunately, they each have drawbacks such as the… 
Negative thermal expansion ALLVAR Alloys for smaller optics
Temperature changes can detrimentally affect an optic’s performance due to changes in radius of curvature, thickness, and index of refraction. This is a particularly tricky problem when combinations
ALLVAR alloy athermalization: a novel and cost-effective alternative for small to moderate sized space telescopes
Design To Unit Production Cost (DTUPC) is of crucial importance to the viability and implementation of constellations which require tens to hundreds of small to moderate sized spaceborne telescopes
Kondo-Induced Giant Isotropic Negative Thermal Expansion.
Using x-ray spectroscopy and diffraction to investigate the 4f-electronic properties in Y-doped SmS and employ the Kondo volume collapse model to interpret the results reveal an unparalleled decrease of the bulk Sm valence at low temperatures in the mixed-valent golden phase.
Characterization of dimensional stability for materials used in ultra-stable structures
Modern observatories including ultra-stable spectrographs, optical telescopes and gravitational wave observatories rely on ultra-stable structures to meet their science objectives. These structures
In Situ and Ex Situ Studies of Tetrammineplatinum(II) Chromate Thermolysis
Comparative analysis have shown that the thermolysis of complex salt [Pt(NH3)4]CrO4 in synthetic air atmosphere under in situ and ex situ conditions proceeds in different routes. In contrast to in


Variable invariables: dimensional instability with time and temperature
  • S. Jacobs
  • Materials Science, Engineering
    Optics + Photonics
  • 1992
How stable are structures made of fused silica, Zerodur, ULE, Invar or Superinvar? We review what is known about dimensional changes with time or temperature for these important materials, including
Mounting optics in optical instruments
This volume gives engineers in the fields of optical engineering and optomechanical design a thorough understanding of the principal ways in which optical components - lenses, windows, filters,
Mounting Optics in Optical Instruments – 2nd edition
  • 2008