<title>IDL fabricating technique: further developments for the liquid and replicated mirrors of very large ground-based and space telescopes</title>

Abstract

ABSTRACT Results of advanced experiments in centrifugal moulding of the mercury parabolic mirrors and convex replicable matrix arepresented and discussed. The stationary ground-based installation was erected following the IDL fabrication technique and put into action. A number of important technical peculiarities of the installation are described along with some theoretical background for its dynamics. The experiments done prove well the IDL-technique prospects in building zenith telescopesemploying liquid paraboloids as working mirrors beyond 10-rn in diarnetres, as well as thin superlightweight replicated mirrorsintended for the NGST-like projects.Keywords: liquid-mirror telescopes, fDL-technique, replicable parabolic matrix, space telescopes 1. INTRODUCTIONA further size-increase of apertures for the ground-based and space-borne telescopes, encourages quest for and developing new-type, non-traditional mirror designs, production technologies, as well as reflecting surface materials. Until nowit has been, in particular, reliably ascertained that the ground-based telescope 8 m-mirrors being thin and/or honey-comb typemay operate perfectly. The required reflecting surface shape, traditionally secured by using solid mirrors, was done by continuedmonitoring and control. To the systems that need continuous control their reflecting surface shape we may also belong liquidparabolic mirror telescopes (LPMT) 2