Infrared and visual lunar occultations measurements of stellar diameters and new binary stars detections at the Calar Alto 1.5 m telescope^*

¹ Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain
² Observatori Fabra, Camí de l'Observatori s/n, 08035 Barcelona, Spain
³ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
⁴ Escola Universitária Politécnica de Barcelona, Universitat Politècnica de Catalunya, 08028 Barcelona, Spain

Corresponding author: O. Fors, ofors@am.ub.es

Received: 16 October 2003
Accepted: 9 February 2004

Abstract

We present a program of routine lunar occultations, at optical and near-IR wavelengths, recently started at the 1.5 m Spanish telescope at the Calar Alto Observatory. Both a CCD and an infrared array detector are used. The program is aimed mainly at the detection and investigation of binary systems, although results in other areas of stellar research are also anticipated. Occultations are reported for a total of 40 stars. Among these, SAO 164567, SAO 78258 and AG+24 788 have been discovered to be binaries, with projected separations as small as . Furthermore, binarity is suspected in the case of SAO 78119 and SAO 79251. Additionally, the angular diameter of the late-type giant 30 Psc and of the infrared star V349 Gem have been accurately measured, the latter for the first time. We finally evaluate the instrumentation performance in terms of the limiting magnitude and angular resolution, and discuss applications to larger telescopes.