Diffraction-limited 800 nm imaging with the 2.56 m Nordic Optical Telescope

¹ Cavendish Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, UK e-mail: jeb@mrao.cam.ac.uk
² Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK e-mail: (CDM) cdm@ast.cam.ac.uk
³ Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Canarias, Spain e-mail: cox@not.iac.es
⁴ Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK e-mail: r.w.wilson@durham.ac.uk
⁵ Division of Astronomy, University of Oulu, PO Box 3000, 90014 Oulun Yliopisto, Finland e-mail: manderse@sun3.oulu.fi

Corresponding author: R. N. Tubbs, rnt20@ast.cam.ac.uk

Received: 8 December 2000
Accepted: 23 January 2001

Abstract

A quantitative assessment is presented of diffraction-limited stellar images with Strehl ratios of 0.25-0.30 obtained by selection of short-exposure CCD images of stars brighter than +6 m at 810 nm with the Nordic Optical Telescope.