Imaging capabilities of hypertelescopes with a pair of micro-lens arrays

¹ LISE-Observatoire de Haute-Provence, 04870 St Michel l'Observatoire, France e-mail: sgohp@obs-hp.fr; lardiere@obs-hp.fr; dejonghe@obs-hp.fr; riaud@obs-hp.fr
² LESIA, Observatoire de Paris-Meudon, 5 Pl. J. Janssen, 92195 Meudon, France e-mail: pierre.riaud@obspm.fr;anthony.boccaletti@obspm.fr
³ Collège de France, 11 Pl. M. Berthelot, 75321 Paris, France e-mail: labeyrie@obs-hp.fr
⁴ Observatoire de Haute-Provence, 04870 St Michel l'Observatoire, France e-mail: schmitt@obs-hp.fr; arnold@obs-hp.fr
⁵ GEPI - Observatoire de Paris, 61 avenue de l'Observatoire, 75014 Paris, France e-mail: david.horville@obspm.fr

Corresponding author: S. Gillet, sgohp@obs-hp.fr

Received: 29 May 2002
Accepted: 15 November 2002

Abstract

We verify the imaging performance of hypertelescopes on the sky, using a new scheme for pupil densification. To avoid seeing limitations, we used a miniature version with a 10 cm aperture containing 78 sub-apertures of 1 mm size, arrayed periodically as a square grid. The pupil densification is achieved with a pair of micro-lens arrays, where each pair of facing lenses behaves like a tiny demagnifying telescope. We have tested the direct snapshot performance with laboratory-simulated multiple stars and observed the binary star Castor (α Gem). We measured a separation of 3.8´´ and a magnitude difference of 0.85 which is in agreement with current orbital data. This verified the theoretical expectations for hypertelescopes in terms of field of view and fluxes and qualified the new optical implementation for future arrays at the scale of meters and beyond.