The Europe Extremely Large Telescope (E-ELT) is the largest ground optical telescope project currently under construction in the world. With its sheer 39m in diameter, it will dwarf the largest telescopes of today. Such monster telescope required a lot of studies to prepare the actual construction phases. AMOS contributed to several of them.
E-ELT’s Design Studies
The European Extremely Large Telescope (E-ELT / ESO) will be the future 39 m diameter explorer of new astronomical frontiers in the next decade. On behalf of ESO, AMOS conducted two design studies addressing telescope subsystems.
M3 Unit design
The Tertiary Mirror Unit consists in a 4m-class mirror supported by an active mount. The purpose of this device is to correct every minute the mirror shape during the telescope tracking. The correction is applied by means of force actuators and aims at keeping an optimized telescope imaging quality.
M4 – design support to CILAS
AMOS also worked on the design of the M4 unit support, as a partner of CILAS.
Study E-ELT pre-focal station
AMOS was contracted by ESO for the conceptual design of the E-ELT Pre-Focal Station (PFS) and its handling and tests facilities. The PFS is located on the Nasmyth platforms of the EELT. The so-called Pre Focal Station is a giant opto-mechanical multi-purpose system, which shall redirect the light beam having entered the telescope to the various analysing instruments of the focal plane.
The pre-focal station has the following functions:
- sending the optical beam to the various instrumentation
- monitoring the quality of the optical beam
- de-rotate the telescope field.
The study consisted in the preliminary design of the pre-focal station in order to determine its future performance and characteristics.
The resulting design was a common framework structure containing 6 main units:
- The axial rotator and the two lateral ones where instruments with a weight up to 5 tons are attached.
- The common adaptor for 4 natural guide star and 4 laser guide probes equipped with wavefront sensors
- The M6G&N unit where 2 mirror modules move in the same hoistway from their parking to their working position.
- The M6C unit moving the M6C up from its parking position down to its working one.
Due to budgetary constraints, ESO had to reduce the scope of the pre-focal station. The PFS-A concept design is however largely inspired from that PFS design.