Technical tests undertaken with the Hypertelescope in Ubaye suggest the feasibility of an Extremely Large Hypertelescope with a kilometric meta-aperture and whose number of mirrors could be gradually increased to contain up to one thousand mirrors.
While the future European “Extremely Large Telescope” (E-ELT) of 39m in diameter requires the construction of a giant mount and a dome, the optical mirror network of an ELHyT unfolds in an open-sky valley. At comparable cost, an ELHyT would therefore have a larger collective surface than an E-ELT. If the feasibility of adaptive co-phasing using a laser guide star were confirmed, the ELHyT would allow obtaining a gain in sensitivity and in limiting magnitude as well as a better resolution. Some high valleys in the Andes and the Himalaya seem appropriate to accommodate an ELHyT.
As with large radio interferometry networks, an ELHyT begins to be operational as soon as the first mirrors are co-phased. Like radio arrays, it can be considered as an instrument in continuous evolution.
The scientific domains that can be addressed with an ELHyT range from stars – stellar physics and exo-planet transits – to active nuclei galaxies and distant galaxies. An ELHyT would particularly allow detecting younger galaxies than those accessible with the Hubble telescope, Keck and VLT.
A. Labeyrie, D. Mourard, F. Allouche, R. Chakraborthy, J. Dejonghe, A. Surya, Y. Bresson, C. Aime, D. Mary, and A. Carlotti. Concept study of an Extremely Large Hyper Telescope (ELHyT) with 1200m sparse aperture for direct imaging at 100 micro-arcsecond resolution. In Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8445, July 2012.