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ZILTA is a supplier of precision science and astronomical Mirrors which was manufactured by Technologic Systems of Automated Machining (TSAM). ZILTA offers high precision mirrors with shape accuracy till ?/80, ?2000mm.
Depending on customer needs ZILTA offers the following
Types of Mirrors:
• Flat; ( best flatness is reached);
• Sphere, Cylinder; Ellipsoid (rotary) ( very good flatness);
• Paraboloids, Hyperboloids; ( good flatness);
• Off-Axis Parabolics; Free Form Aspherics ( good flatness);
Substrate Material:
  • Zerodur®, Astrositall®( Sitall CO-115M)
  • Fused Silica
  • Glasses (Pyrex, BK7, …)
  • Silicon (single crystal)
Other materials are available.
  • all types of Metallic coatings;
  • custom dielectric coatings for 200 – 5000 nm;
  • e-beam evaporation with/without Ion Assisted Deposition (IAD).
You are welcome to submit inquiries regarding the optics, accompanied by Your specifications!
Please fill our request form for price quotation and delivery.
Sitall CO-115M (Astrositall®)
SITALL СО115М is a crystalline glass ceramic material with ultra low Coefficient of thermal expansion. SITALL СО115М is an ideal material to be used for manufacturing of astronomical telescopes mirrors and other optical parts that require linear dimensions and surface figure stability at significant temperature changes. Thermal stability of SITALL material enables the fabrication of high precision mirrors within quicker time of treatment process since testing measurements are able to be conducted not waiting until thermal equilibrium is achieved.
Astrositall blanks with various forms of lightweightening
mean linear coefficient of thermal expansion (CTE)
within temperature range -60 to 60 oС
10-7 oC-1 0±0.6
CTE homogeneity 10-7 oC-1 < 0,2
specific heat capacity kJ kg-1 oC-1 0.22
heat conductivity kilocalorie h-1 m-1 0C-1 1.71
thermal resistance 0C 550
density g cm-3 2.46
micro hardness 107Pa 786
lapping relative hardness
(with reference to glass, K-8 type)
- 1.78
modulus of elasticity (Young’s) GPa 92
bending strength 107Pa 16.6
Poisson’s coefficient - 0.28
refractive index ne - 1.538
refractive index nd - 1.536
average variance nF - nC - 0.0102
stress birefringence nm/cm up to 15


Please see Typical Mirror Surfaces on:



Z I L T A Co. unlimited © 2019, Lithuania European Union, Fax: +370 7000 4444, E-mail: zilta[eta]

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