Title: Aucun titre de diapositive
1ASTRONOMY INSTRUMENTAL ACTIVITIES
- SESO was founded in 1965 to meet the needs of
large, multinational, astronomical observatories.
Currently, SESO remains a major supplier of
astronomical devices. - To fulfil increasingly difficult requirements,
SESO has developed specific technologies in
different fields such as - Optical design,
- Manufacturing tolerance analysis,
- Mechanical design,
- Aspheric mirrors and lenses,
- Polishing,
- Optical cementing and contacting,
- Optical coatings,
- Mechanical integration.
2POLISHING AND CEMENTING
- POLISHING
- All type of glass or crystal or metal
- Up to 1.4 m CaF2 up to 300 mm
- Control by interferometry
- Spherical, aspherical
- POST-POLISHING ON ASPHERICAL SURFACES
- Aspherical surface on CaF2 post-polished after
diamond turning
Roughness achieved lt 20 Ã… RMS
3ASPHERICAL CALCIUM FLUORIDE LENSES
PHOTOGRAPH (with the courtesy of LAS)
4POLISHING AND CEMENTING
- SUPERPOLISHING
- In the framework of X-Ray mirrors for
synchrotrons use, SESO has developed
super-polishing technique (surface roughness lt 2
Ã… RMS) on different materials. This technology is
useful in the case of solar experiments - CEMENTING
- Suitable optical cement for gluing large lenses
with different CTE to withstand storage
temperature (- 10C to 40C). - This technology has been applied, for instance,
on quadruplet of VIMOS/CAM or doublet of UVES red
camera.
5UVES SUBSYSTEMS EXAMPLE Uves Blue and Red Camera
250 mm
Ø 220 mm F 360 mm blue camera made of 7
lenses. Ø 245 mm F 500 mm red camera made of 8
lenses. Image quality 20 of energy in a spot
of less than 20 µm diameter Athermalization in
order to avoid focussing devices and associated
electronic and software
6VIMOS AND NIRMOS SPECTROGRAPH SUBSYSTEMS
EXAMPLES Focal plane assembly lenses
7COMPUTER CONTROLLED POLISHING MACHINE
8Flat mirror of 600 mm diameter
9Off-axis parabola with 20 off-axis
10Off-axis parabola with 20 off-axis
11SURFACE QUALITY OBTAINED BY C.C.P. Real
interferogram example for 1 meter diameter
parabolic mirror Surface quality l/54 RMS
12EXAMPLES OF OPTICAL COATING Wideband anti
reflection coating on a 8 lenses objective (from
365 nm to 1000 nm)
13EXAMPLES OF OPTICAL COATING Enhanced Silver
coating results (from 350 nm to 800 nm)
14EXAMPLES OF OPTICAL COATING Hard Gold coating
results (from 0.7 µm to 25 µm)
Wavelength (µm)
15NASMITH CORRECTOR FOR V.L.T. Two lenses of 900 mm
diameter in their mount