Precision Glass and Optics (PGandO) has delivered specialised optical mirrors to Texas AandM University and the University of Texas at Austin.
These will be used in building the first-of-its-kind Visible Integral-field Replicable Unit Spectrograph (VIRUS) instrument, a key part of the Hobby-Eberly Telescope Dark Energy Experiment or HETDEX.
The VIRUS will be used in HETDEX to study the mysterious force that is causing the expansion of the universe to accelerate.
The $36m (?22m) international research project will study the force that causes the expansion of the universe to speed up, rather than slow down.
This unknown force, dubbed by scientists as 'dark energy', is analogous to throwing a ball into the air and realising it is speeding up as it flies into the sky, rather than slowing down and returning.
Since dark energy makes up over 70 per cent of the universe, understanding this mysterious force is considered one of the top challenges in physics today, according to HETDEX researchers.
The VIRUS system comprises 150 small, individual replicas of a single spectrograph.
The optical mirrors provided by PGandO for the VIRUS collimator fold mirror were specified for operational wavelength range of 345 to 700Nm and are optimised from 350 to 590Nm with average reflectivity of greater than 99 per cent and greater than 95 per cent between 345 and 700Nm.
The absolute reflectivity is greater than 98 per cent between 350 and 590Nm and greater than 92 per cent at 345 to 700Nm.
Angle of incidence is at 12.5+/-5 degrees.
This coating also has to perform in extreme environmental conditions (-25C to +66C) and to meet Mil-C-48497 abrasion/adhesion durability standards.
PGandO provides high-performance optical components and thin-film coatings for challenging tasks.
To meet the requirements for VIRUS, the reflective coatings on borosilicate glass have an operational lifetime of 20 years.
The massively replicated VIRUS instrument will be assembled, aligned and tested within the Charles R'62 and Judith G Munnerlyn Astronomical Laboratory at Texas AandM and in the laboratories of the McDonald Observatory at the University of Texas.
Darren DePoy, professor of physics and astronomy and Munnerlyn Laboratory director, and Jennifer Marshall, research scientist, will lead the effort at Texas AandM.
Gary Hill, research professor and Sarah Tuttle, postdoctoral research associate, will lead the effort at the University of Texas.
The astronomical instrument is designed to gather light from distant galaxies and split it into individual spectral wavelengths.
The spectrum will reveal an object's chemical composition, its temperature and the speed at which the universe is stretching between the detected galaxies and Earth.
VIRUS will capture spectra from 33,000 points on the sky simultaneously, using fibre optics to transfer the light from the Hobby-Eberly Telescope (HET) focal plane to the huge replicated array of spectrographs.
This will permit HETDEX astronomers to produce a three-dimensional map of a large volume of space, indicating how fast the universe expanded at different periods in history, which will help reveal the role that dark energy has played during different eras.
It will search for any evidence that the strength of dark energy changes over time and also will provide the most precise measurement of the geometry of the universe, which is related to the physics of the universe at the moment of Big Bang.
DePoy says that because VIRUS is designed for spectroscopic observations of a large number of objects simultaneously, the instrument is well-suited to measure the subtle effects that dark energy has on the structure of the universe.
Its power will also enable a broad range of other astronomy projects.
