Puzzles like this soon to be solved thanks to an international team led by scientists and engineers in Scotland
28 June 2019 – The ‘eye’ of one of the world’s most advanced telescopes is soon to become even more powerful, thanks to the work of an international team led by scientists and engineers in Scotland. A new ground breaking astronomical instrument is currently being built in Scotland that will soon allow astronomers to ‘see through’ cosmic dust and study in ‘never-been-seen-before’ detail the innermost regions of our Milky Way – to solve astronomical puzzles such as how our Milky Way took shape!
During its 10-year design lifetime this new astronomical instrument, called MOONS, is expected to observe in the order of ten million objects. By viewing objects up to 40,000 light-years from the Earth, astronomers will be able to see in unprecedented detail the innermost regions of our galaxy, the Milky Way. Not only that, MOONS will allow astronomers to see across even more vast distances so that they will be able to study the formation and evolution of galaxies over the entire history of the Universe.
MOONS is a unique astronomical instrument which is being designed, built and assembled at the UK Astronomy Technology Centre (UK ATC) in Edinburgh, in collaboration with an international consortium of institutions and commercial partners. The next generation Multi-Object Optical and Near-infrared Spectrograph, MOONS, will be operational in 2021 on the European Southern Observatory’s (ESO) Very Large Telescope (VLT) at the Paranal Observatory in Northern Chile.
Dr Oscar Gonzalez, Instrument Scientist at UK ATC, says “To explore galaxy formation and evolution we need to investigate the properties of millions of stars from the very centre of our own galaxy to as far away as the other millions of galaxies in the early Universe. For example, to understand how our galaxy reached its current form, we need to map in detail its innermost regions. This is tremendously challenging because of the large amounts of dust between us, and the stellar populations we need to target.
“MOONS is able to observe in the Infrared, and so we will finally be able to ‘see through’ the dust.”
In a marriage of precision and scale, two significant technical milestones in the design and build of MOONS have now been achieved. These technical milestones, one in the development of robotic arms to assist in the alignment of the telescope with celestial objects in the sky, and one in optics, are important because the cutting edge capability of MOONS is in turn demanding cutting edge design to push the boundaries of technical innovation, and blaze a trail for future spectrographs.
Precision-engineered robotic arms
“One thousand small robotic arms are at the heart of the MOONS instrument.” says Dr William Taylor, Instrument Scientist at UK ATC. “Called Fibre Positioning Units (FPUs), these robotic arms move quickly and with an accuracy of about the width of human hair (25 microns), to allow the telescope to align with about 1000 celestial objects, at the same time! It is now all systems go on delivering a production run of 1000 of these robotic arms”
“It’s been a complex design challenge,” continues William. “The FPUs sit on a large focal plate measuring over 1m in diameter and are monitored as they move around each other by 12 cameras. Interspersed throughout the FPUs are a further 20 cameras which are responsible for the fine alignment of the instrument with objects in the sky. With the design now tested and validated, 1000 FPUs are currently being manufactured and will soon be delivered to us here in Edinburgh for assembly.”
Very large optics
At the magnitude of celestial observing required of MOONS, the new instrument needs very fast, and very large optics to capture the light from as many astronomical targets as possible in a single shot. The optical design of the MOONS cameras, which will sit within the incredibly low temperatures of a 7-tonne cryostat, is a ground-breaking never-been-done-before technical innovation.
“It’s the green light for the alignment of the cameras after the successful mounting of the incredibly large and tricky-to-handle 40cm lenses into the camera housings.” says Dr David Lee, Optical Engineer at UK ATC.
“The design and construction of the cameras is a multi-disciplinary, multi-organisation achievement involving colleagues in Italy, France and England,” continues David.
“What makes the camera so novel,” adds David, “is that it has been specifically designed to have fewer optical components, with the aim of making the alignment easier. Essentially, two lenses have been glued together – a smaller lens inside a larger lens, which is an alarming idea, because of the constraints this puts on the glass during the cooling process. But the beauty in the idea is that there are only two optical elements to align – so whilst one is held still, the other can tilt to focus.”
Notes to Editors
The design and construction of the cameras is a multi-disciplinary, multi-organisation achievement involving colleagues in Italy, France and England. UK ATC have worked with INAF in Florence on the design; manufacturing is being done by Winlight Optics in France; while the mechanical housings have been developed at the University of Cambridge.
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. ESO provides state-of-the-art research facilities to astronomers and is supported by Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile.. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising co-operation in astronomical research. It operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor.
Last updated: 27 June 2019