Prof Gavin Dalton

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 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.

Abstract:

The science case for the next generation of Extremely Large Telescopes (ELTs) covers a huge range of astronomical topics and requires a wide range of capabilities. Here we describe top-level requirements on an ELT, which were derived from some of the key science cases identified by European astronomers. After a brief summary of these science cases we discuss the requirements on the ELT system in terms of several parameters, including wavelength range, field of view, image quality etc. We discuss the science driver that sets the limits on each parameter. We also discuss specific requirements on instrumentation, site and adaptive optics. In several cases, detailed simulated observations will be required in order to set the requirements. While the example science cases provide a useful guide, we also note that an important goal is to develop a facility that covers a broad parameter space, and maintains flexibility in order to adapt to new scientific directions.