A new camera mounted on hypertelescopes will allow astronomers to take pictures of several stars at once and capture high-resolution objects outside our solar systems, such as planets, pulsars, globular clusters, as well as distant galaxies.
“A multi-field hypertelescope could, in principle, capture a highly detailed image of a star, possibly also showing its planets and even details of the planets’ surfaces,” explained Antoine Labeyrie, a Professor at the Collège de France and Observatoire de la Cote d’Azur, and pioneer in the design of the hyper telescope.
“It could allow planets outside our solar system to be seen in enough detail that spectroscopy can be used to search for evidence of photosynthetic life,” the researcher revealed.
In the journal Optics Letters of The Optical Society (OSA), Labeyrie and his colleagues report optical modeling results verifying that their multiple field design can substantially extend the narrow field of view coverage of hypertelescopes developed to date.
As revealed by the scientists, large optical telescopes utilize a concave mirror to focus light from celestial sources. Although larger mirrors can produce more detailed images due to their reduced light beam scattering, there is a limit to the size of these mirrors. Hypertelescopes are designed to overcome this size limitation by using large sets of mirrors, which can be widely separated.
Previous research has seen scientists experiment with relatively small hypertelescope prototype designs, and a full-size version is currently under construction in the French Alps.
In the new paper, the researchers used computer models to create a design that would give hypertelescopes a much wider field of view.
This revolutionary design could then be used to build hypertelescopes on the surface of our planet, on the lunar surface, tucked away in a crater on the moon, or even no a massive scale in space.
Building a hypertelescope in space, for example, would require the assembly of a large flotilla of small, spaced mirrors that form a very large concave mirror.
The large mirror would then focus light from a star or other celestial objecst on a separate spacecraft carrying a camera and other necessary optical components.
“Multi-field design is a fairly modest addition to a hypertelescope’s optical system, but it should greatly enhance its capabilities,” said Labeyrie.
A final version deployed in space could be ten times larger in diameter than Earth and could be used by astronomers to reveal details of extremely small objects like the Crab pulsar, a neutron star believed to be roughly 20 kilometers (12 mi) in diameter.
Hypertelescopes use what is known as pupil densification to concentrate light collection and form high-resolution images. However, this process greatly limits the field of view of hypertelescopes, preventing imaging of diffuse or large objects, such as a globular star cluster, an exoplanet system, or even a galaxy.
Scientists have developed a micro-optical system that can be used with the hypertelescope’s focal camera to simultaneously generate separate images of each field of interest.
For star clusters, this enables separate images of each of thousands of stars to be obtained simultaneously.
The proposed multiple field design can be viewed as an instrument made of multiple independent hypertelescopes, each with a differently inclined optical axis that gives it a unique image field.
These independent telescopes focus adjacent images on a single camera sensor.
Researchers used optical simulation software to model different implementations of a multi-field hypertelescope, resulting in accurate results that confirmed the feasibility of observations from multiple fields.
However, scientists revealed that incorporating the addition of multiple fields into hypertelescope prototypes would require the development of new components, including adaptive optics components to correct residual optical imperfections in off-axis design.
The researchers also continue to develop alignment techniques and control software so that the new cameras can be used with the prototype telescope in the Alps.