Dark Energy Spectrographic Instrument development

Lead Research Organisation: University College London
Department Name: Physics and Astronomy


DESI is a ground-based dark energy experiment to study the cosmological expansion rate and the growth of structure with a wide-angle spectroscopic galaxy and quasar redshift survey. In order to undertake the proposed survey, a US-Europe-China collaboration has come together with the aim of constructing a 5000-fibre spectrograph that will be deployed on the Mayall 4m telescope at the Kitt Peak Observatory in the US. A wide range of additional science is possible using the 5000 fibre multi-object spectrograph required for this experiment, including studying galaxy formation and evolution, galaxy cluster surveys, the structure of the Milky-Way galaxy and Galactic archaeology.

The UK has internationally regarded expertise in several key areas of the proposed instrument, in particular being involved in the the optical corrector (consisting of six nearly metre sized optics), and the fibre system that takes the light from the focal plane to the spectrograph. The proposed research enables the UK to be involved in the optical and mechanical design and development work leading to the full instrument specification.

Planned Impact

Skill development: The DESI project will develop the skills of ~10 PhD students and ~4 technical staff. The PhD students will be mostly in the data processing and data analysis areas. The technical staff will mostly be in the instrumentation area.

Fibre system: The massively multiplexed fibre system of DESI provides a significant technical challenge in developing an efficient coupling to the DESI spectrographs. Techniques to be investigated in this study could have wide applicability to spectral image reformatters based on optical fibres and applied in fields as diverse as process inspection and remote diagnostics, where access to the target area is restricted.

Optical system: The DESI optical system comprises of lenses of 0.8-1.25m in diameter which need to be aligned to within tolerances of approximately 100 micrometers. This poses a major challenge to the mounting and alignment of the lenses along with the testing of the complete system. Advances in mounting and alignment of large lenses coupled with large optics production developments at OpTiC, North Wales, give the UK the potential to produce large optical systems for use, for example, in proposed high power laser facilities such as the High Power laser Energy Research facility (HYPER).


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Doel Peter (2014) The DESI wide field corrector optics in Ground-based and Airborne Instrumentation for Astronomy V

Description The research enabled UCL to be involved in the design and development of the planned Dark Energy Spectroscopic instrument. This will be a major facility the data from which will be very beneficial to the UK science community
Exploitation Route This research has led to the UK having a major role in the construction of the DESI instrument
Sectors Aerospace, Defence and Marine,Education,Other

Description This work has led to the UK taking a leading part in the Dark Energy Spectroscopic instrument project. This is a major international project that will build a 5000 fibre spectroscopic instrument on the Mayall 4m telescope.
First Year Of Impact 2014
Sector Education,Other
Impact Types Societal,Economic

Description STFC projects
Amount £742,939 (GBP)
Funding ID ST/M00287X/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 01/2015 
End 12/2019