Lunar optical interferometry and hypertelescope
Hypertelescope capable of direct high-resolution imaging with a high limiting magnitude became tested on Earth, proposed for space, and is now also proposed for the Moon.
Many small mirrors can be dilutely arrayed in a lunar impact crater spanning 10 to 25km.
And a larger version, modified for a flat lunar site and spanning up to several hundred kilometers can be later built if needed for a higher resolution and limiting magnitude.
The imaging resolution expected is reaching 100 nano-arcsecond on the Moon.
Nested Lunar Hypertelescope (NLH) with cable-suspended focal optics
The “Ubaye hypertelescope” terrestrial prototype is a fixed-mirror array, nested in a deep valley. Its focal optics is suspended from a single crossing cable, and 6 oblique tethers actuated by small winches control its position and attitude while it tracks the focal image of the observed star. It does not require optical delay lines, and may thus have hundreds of sub-apertures, a significant advantage compared to interferometers such as the VLTI.
The experience gained in a decade of testing (10) suggests that it can be replicated in a lunar impact crater (fig.1) if and when a manned lunar station becomes installed. The possibility of a fully robotic construction and operation on the Moon also likely exists, but currently lacks maturity.
Figure 1: Sketch, at approximate scale, of a Crater-Nested Lunar Hypertelescope, with its focal receiver suspended from cables and movable along the focal surface (fine dotted arc). The locus of the mirror array (fat dotted arc) is either paraboloïdal, actively deformable by applying small tip-tilt-piston corrections on its segments, or fixed and spherical if a corrector of spherical aberration is added in the focal optics. No delay lines are needed, but the meta-mirror size is limited to about 20 km by the maximal 6km depth of impact craters, for an effective meta-aperture of 5 to 10km. The mirror elements are either carried by separate fixed tripods or by a hammock-like cable netting .
Concept for a Larger and Flat Lunar Hypertelescope (LFLH)
For a large array, nearly flat at the scale of several hundred kilometers, optical delay lines are needed. Two possible geometries are sketched in fig. 2 A and B
Figure 2: Sketch of two variants A and B for a Larger and Flat Lunar Hypertelescope (LFLH). The optical delay lines needed with a flat array of mirrors, coplanar with the combined focus and science camera, can be achieved with extra flat mirrors, movable and arranged as a hierarchy of deformable elliptical loci.
Figure 2.A Plan view of mobile M1 mirrors carried on flat ground by legged robotic rovers. They can be distributed along an ellipse, deformable about one of its foci, for reflecting beams from an observed star toward it, while maintaining their coherence. The ellipse is the intersection of the flat ground with a paraboloïd aiming the star and confocal with said ellipse, thus ensuring equal optical paths from the star to the focus. A hierarchy of ellipses can be used.
Figure 2.B Primary mirror elements M1i can be kept fixed, at arbitrary positions, but with tip-tilt actuators, if they feed as many facing mirrors M2i, radially movable for serving as delay line elements. The M1 mirrors located at the outer edge, such as M1j, require no delay line if they are mobile.
Figure 2.C A beam-combining pseudo-conical mirror with flat facets combines all beams into a densified pupil. And a lens co-focuses them on the camera.
The M1 mirrors can be sized in the meter range or smaller, and number in the hundreds or even thousands if the “flat” ground has a shallow curvature (some bumpiness of the ground surface can also be tolerated if it does not obscure the horizontal light beams). Additional fine corrections are achievable for tracking and co-phasing, with micrometric actuators incorporated in the focal beam combiner. No rail tracks or piers are needed if legged robotic rovers can smoothly carry the mirror segments and control their attitude.
The optimal lunar latitude for a site is a trade-off between its thermal cycling amplitude and the sky coverage achievable toward the North and South. A 60° latitude, North or South, may be a good choice. The moon’s far side also offers a protection against Earth shine.
A new kind of telescope is born
Optical astronomy techniques are constantly evolving. The largest telescopes being planned around the world are now reaching 40 m in diameter for their primary mirror. However the methods, materials and financing capabilities that have enabled the production of such colossi reach their limits.
For the astronomical challenges of the future, we will always need to get better images of smaller and more distant celestial objects. Therefore, it becomes necessary to create a brand new form of optical instrument which could overcome physical constraints and move to all-new size scales, at lower costs.
It is the essence of the scientific project proposed by Antoine Labeyrie since 1996 and that he called: HYPERTELESCOPE.
The telescope of the future
An innovative project, a world premier.
The Hypertelescope is a giant telescope pushing away the frontiers of the invisible
Thanks to its revolutionary architecture invented by Antoine Labeyrie, the Hypertelescope overcomes size limits that restrict the traditional telescopes of today.
The development of Imaging by interferometry techniques allows to a Hypertelescope “Carlina” to be equipped with a diluted primary mirror. It is constituted of multiple mirrors which form together the fragments of a unique mirror without limits of dimensions. This founding principle makes it an evolutionary tool and multiplies its performance and its possibilities. Its production costs are incremental and largely lower than those of the very large telescopes currently in development, for much higher yields.
An Hyper-Telescope is a discrete and sporadic structure wich allows to see farther in space. It dissolves itself in its environment. And its modes of operation correspond with a facility in the middle of wild, classified and protected natural mountain sites.
We are now free to imagine a new generation of optical tools for astronomical observation that will surpass the capabilities of everything that already exists or is in project over the world.
Antoine Labeyrie, now Professor Emeritus at the College de France. It is a pioneer of Astronomical Interferometry. He imagined and began to realize in the Alps of the South, with its teams, a first prototype of giant telescope at the top of the mountain: the Hypertelescope.
See bigger. See farther.
A first prototype of Hypertelescope type “Carlina” is currently under study in France in the Ubaye Valley in the Alps of Haute Provence. When it is completed, it will be 200 m in diameter. With 800 mirrors 15cm, it will accumulate two times more of collecting area than the Hubble Space Telescope and a visual acuity almost one hundred times greater. It will be five times as powerful in resolution that the future EELT from 39 m in diameter whose construction is scheduled for 2024 by ESO to the Chile.
But this is just the beginning. The scientific team has estimated that we could build a Hypertelescope extra large with a diameter of the order of 1 km and install it in the depression of a former impact crater, in the crater of a dormant volcano or some high valleys of the Andes or of the Himalayas.
In a final version, deployed in space, the Hypertelescope diameter may be extended at least eight to ten times more than the diameter of the Earth. And at these dimensions, it will produce with sharpness some images of the surface of an extrasolar planet at approximately 10 light years of our system !
The Mountain Telescope
The principle of the hypertelescope : the particularly innovative design of the hypertelescope with the ” Carlina ” architecture is to replace the single mirror of conventional telescopes by a ” diluted miror “, that is composed of many non full complement small mirrors, positioned very precisely, to form them all a giant virtual concave mirror.
The capacity of the hypertelescope : one considers that, for a telescope, the biggest is the mirror surface which collectes the light, the more reach, the deepest and more detailed the image will be. The system of the Hyper-telescope type Carlina offers the possibility to considerably increase this surface without increasing the material difficulties by multiplying number of small mirrors. This allows us to exceed the current dimensions of the very large telescopes currently in project without problem.
The effectiveness of the hypertelescope : the diameter of the mirror of a telescope – the distance separating the two furthest edges of a mirror – determines its ability to separate the finest details of the target stars. By its dimensions dozens of times bigger than conventional telescopes, the visual acuity of a Hypertelescope will reach thresholds never yet touched
The dimensions of the hypertelescope : by its splited form, there is no limit to the number of mirrors that make up a hypertelescope. We can associate a large amount of mirrors together to get a greater light collecting area in total. There is no theoretical limit of distance between the small mirrors for a hypertelescope. And so the diameter of the Hypertelescope can take the dimensions of a simple swiming pool or the one of the hollow of a volcano or a mountain valley…
The costs of the hypertelescope : the manufacture, transport and installation costs of a hypertelescope’s mirrors are very reduced compared to a very large conventional telescope mirror, as the E – ELT, and for a greater collecting area. For an equal surface and for the same amount of light collected, we calculated that the cost of a Hypertelescope will be much lower. Eventually, a Hypertelescope device offers a greater collecting area at lower cost.
The possibilities of the hypertelescope : the Hypertelescope system allows to install and operate several optical devices at the same time over a same telescope mirror. It permits to practice as much simultaneous observations of different objects in the sky with exactly the same technical specifications. In practice, each optical device will add a new telescope to a telescope already built for incredibly reduced cost. Thus, a hypertelescope, is also a multi-telescope.
Plusieurs nacelles pour un Multi-télescope.
A Green Science instrument
“The hypertelescope blends into the mountain and made body with it”
The first prototype of the Hypertelescope is being developed since the summer 2011 in the Alpes de Haute-Provence, in France. The site of the Valley of the Moutiere, chosen for its astronomical qualities, is submitted on his side North to the regulation of the Office National des Forêts (ONF) and on its side South of the National Park of Mercantour (PNM).
The hypertelescope fits into nature with the greatest respect for the delicate balance of its wilderness, wildlife and local flora. Its installation requires no environmental processing and generates no visual, audible, nor hardware pollution.
More informations (PDF) : http://hypertelescope.org/fiches-techniques/documents/hypertelescope-optical-observatory/
An international scientific association
A citizen science project that pushes the frontiers away
The project of the Hypertelescope is developed by an international team (France, USA, Spain, Canada, India, Algeria…) of scientists, researchers, engineers, teachers, technicians, mechanics and amateur astronomers gathered under the direction and the chairmanship of Antoine Labeyrie and Denis Mourard.
Since the year 2014 and the retirement of Professor Labeyrie, the project initially supported jointly by the College of France and Obresvatoir de la Côte d’Azur, can no longer receive the direct support of these prestigious institutes.
The Association Hypertélescope LISE – Laboratoire d’Interférométrie Stellaire et Exoplanétaire – was then founded in August 2014, to support the Hypertelescope project and meet the needs of the scientific teams from all walks of life in the human resources, administration, logistics and funding.
Our commitment, today, for the future
“See farther, see bigger”
The hypertelescope, is the future. The future as we plan. A future more harmonious and more respectful of the human and natural environment that welcomes us. More balanced between men of all backgrounds, from all backgrounds, of all, so that the image of each mirror of the Hypertelescope, each combines its clusters of activity and participates in the development of the common good.
This object, the Hypertelescope LISE association is a body which promotes:
- A citizen science within the reach of all, by all and for all, open to the world both in its publications for its internal resources.
- A synergy of the different spheres of society: public, private, associative and personal.
- An alliance of all the know-how in different poles of activity, scientists, engineers, technicians, industrialists and financiers, professionals and enthusiasts, on a joint development project.
- Planetary and exo-planetary issues, which are intended to offer humanity the means of knowledge and the questions for the centuries to come, beyond the established boundaries of corporations and States.
- A natural environment respected, preserved in its wild state and highlighted in all phases of development and in all their aspects, research, installation, energy, logistics, accommodation, with particular care, attention at all times, to the harmony of the scientific tools and personnel with the fauna, flora and the elements that host.
Because at the root of all the major advances of humanity, of all the discoveries, there are new tools, and because the depths of space tell us about our origins, of our destiny, the Hypertelescope LISE association supports the telescope of the future project.
The hypertelescope invites you to the experience of participatory science.
“Small mirrors make the big telescopes…”
Each contribution counts !
The association Hypertélescope LISE, in an object of citizen science, works actively to support the development of the project of giant telescope by interferometry invented by Antoine Labeyrie. Help us to continue and accomplish this great project.
You do not necessarily need to be a billionaire to help to the project…
The project of the largest telescope in the world is worn at arms length by a handful of men and women volunteers and enthusiasts. The future of this beautiful project does the will of men. If you want to make your contribution to the building, the association offers several simple actions.
Each membership gives us more weight. Each contribution made us a big step.
Directly from our site web hypertelescope.org or mail choose the option that suits you:
You can become a member of the association and get involved in the adventure.
Fill out our registration form and enter fully into the”citizen Science”.
You can help finance the operation and development of the project.
Support significantly the activities of the association through monetary and material donations.
You can actively participate to achieve the project of the future telescope.
Get involved with scientists and engineers in this scientific adventure.
You can promote the project around you and on social networks.
Show your support to your loved ones and thus contribute to the popularity of the hypertelescope.
Your requests for information and your comments will be studied carefully by the team. We will reply you as soon as possible. Thank you.
Association Hypertélescope LISE
Laboratoire d’Interférométrie Stellaire et Exoplanétaire
18 avenue Frédéric Mistral