Extremely Large Telescope

Abstract:

This paper describes the design and development of an accurate temperature compliant lens mounting technique being used on the camera of the UK-FMOS near infrared spectrograph for operation at the Subaru Telescope in Hawaii. A series of fused silica lenses of up to 4.4kg, 255mm in diameter and operating at temperatures as low as 70K are supported within flexures cut away from stainless steel outer rings. Intermediate low thermal expansion pads are attached to these flexures and in turn bonded to the glass during the alignment process. This mounting method lends itself to the domino chips type of assembly process which can be carried out on a rotary table to maintain accurate axial alignment. A detailed description of the overall design progression including the methods of manufacture, alignment process, adhesive selection, assembly methods and testing is included.

Abstract:

We present the SWIFT image slicer and its novel de-magnifying design. It is based on the MPE-3D and SPIFFI image slicers, uses plane mirrors to slice the input field, but achieves a considerable de-magnification through the use of a mosaic of spherical lenses. As only plane and spherical surfaces are used in the design, classical polishing techniques can be applied to achieve very high surface accuracy and quality. This reduces aberrations and scattered light, mandatory for an image slicer working at optical wavelengths and behind an adaptive optics system. Except for the lens mosaic, the SWIFT slicer is built entirely from Zerodur and is assembled using optical contacting. We present a detailed description of the design as well as results of the early stages of its fabrication.

Abstract:

The Fiber Multiple-Object Spectrograph for Subaru Telescope (FMOS) is quite large instrument composed of the prime focus unit, the fiber bundle unit, and the two infrared spectrographs. Among these units, a part of the prime focus unit and one of the spectrograph were transported from Kyoto University to the Subaru observatory in the middle of 2005. We present the optical and the mechanical components of the spectrograph, which was reassembled on the new floor of the Subaru dome. We also show the preliminary results of the optical alignment and the cooling test of the instrument at the summit of Mauna Kea.

Abstract:

We describe the build phase of the UK FMOS spectrograph, a 200 fibre cooled OH Suppression infrared spectrograph being constructed as part of Subaru's Fibre Multi Object Spectroscopy facility. Here we describe recent UK activities within the FMOS programme and the likely schedule for commissioning at Subaru.

Abstract:

We describe the integration and test phase of the construction of the VISTA Infrared Camera, a 64 Megapixel, 1.65 degree field of view 0.9-2.4 micron camera which will soon be operating at the cassegrain focus of the 4m VISTA telescope. The camera incorporates sixteen IR detectors and six CCD detectors which are used to provide autoguiding and wavefront sensing information to the VISTA telescope control system.