Newton STFC-NARIT: EXOhSPEC (Exoplanet high-resolution Spectrograph)

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The project is to realise a new kind of high-resolution spectrograph in routine operation. The concept relies on separating the complexity introduced by Earth from the requirements of the spectrometer unit itself. This separation enables a massive reduction in size and complexity on the spectrometer side and it is the natural complement to Adaptive Optics technologies being developed at NARIT and elsewhere. The concepts demonstrated with EXOhSPEC can be used to save tens of millions of pounds in instrumentation costs on the coming generation of extremely large telescopes but also be reproducible by University, public and amateur observatories and offer a competitive alternative to the purchase of large inefficient Fourier transform spectrometers in the wider marketplace. The key developments that we wish to demonstrate are, (1) a compact inexpensive design that can achieve the same performance as existing instruments in terms of wavelength coverage and spectral resolution and (2) bespoke active metrology/actuation of the system to achieve -or even surpass- the best wavelength calibration stability at a fraction of construction and operation costs and to produce a facility instrument. While the prototyping for this instrument is at the University of Hertfordshire, the facility instrument will be produced in Thailand but with the insight gained from operating a prototype versions on the 0.7m Astropark telescope at NARIT headquarters as well at that the Thai National Telescope. The Thai government has made a large investment in the National Astronomical Research Institute of Thailand and so they have the new laboratories in which to build the instrument as well as immediate access to telescopes. Current high-resolution spectrographs are large, expensive and sometimes difficult to maintain and limited to an elite handful of universities and laboratories around the globe. Moreover, because these instruments are so expensive, technology cycles and designs have evolved very little and do not take advantage of the great quality improvement and reduced costs of new materials and mass produced optics. One of the key findings of our prototyping is that the tapering of graded-index fibres is an efficient focal reduction of fibre optic signals not limited by geometrical optics. The optimisation of this by Thai specialists may prove to be a key spinoff of the project. The economic development and welfare of a country relies on key infrastructure and the capabilities of the workforce. In the field of physics and in particular astrophysics, the ability to design and make instruments and to measure and interpret the properties of the transitions in other planets, stars and galaxies is a key cornerstone to understand the properties of the Universe. High-resolution spectroscopy has for decades being a primary tool of astrophysics and a driving force in enabling new fundamental astrophysics. From the discovery of planets around nearby stars to the direct measurement of the size of the Universe. Worldwide, the most oversubscribed instruments on telescopes have long been the high-resolution spectrographs. Although Thailand has a large telescope and a number of smaller ones it does not have a high resolution spectrograph. The proposal is aimed at using Overseas Development Aid funding to develop Thai infrastructure and capabilities while at the same time deepening a collaboration which has been already been technically and scientifically productive and also have long-term benefit to the UK scientists and engineers involved in the project.