Iqueye, a single photon-counting photometer applied to the ESO new technology telescope

¹ Department of Information Engineering, University of Padova, via Gradenigo, 6/A, 35131 Padova PD, Italy e-mail: giampiero.naletto@dei.unipd.it
² CNR/INFM/LUXOR, Padova, Italy
³ Department of Astronomy, University of Padova, Italy
⁴ INAF Astronomical Observatory of Roma, Italy
⁵ Italian Space Agency, Rome, Italy
⁶ Interdipartimental Center of Studies and Activities for Space (CISAS) “G. Colombo”, University of Padova, Italy
⁷ ICFO - Institute of Photonic Sciences, Barcelona, Spain
⁸ INAF Astronomical Observatory of Catania, Italy
⁹ INAF Astronomical Observatory of Cagliari, Italy
¹⁰ Observatoire de Meudon, France
¹¹ INAF Astronomical Observatory of Padova, Italy
¹² Department of Mechanical Engineering, University of Padova, Italy

Received: 10 July 2009
Accepted: 15 September 2009

Abstract

Context. A new extremely high speed photon-counting photometer, Iqueye, has been installed and tested at the New Technology Telescope, in La Silla.

Aims. This instrument is the second prototype of a “quantum” photometer being developed for future Extremely Large Telescopes of 30–50 m aperture.

Methods. Iqueye divides the telescope aperture into four portions, each feeding a single photon avalanche diode. The counts from the four channels are collected by a time-to-digital converter board, where each photon is appropriately time-tagged. Owing to a rubidium oscillator and a GPS receiver, an absolute rms timing accuracy better than 0.5 ns during one-hour observations is achieved. The system can sustain a count rate of up to 8 MHz uninterruptedly for an entire night of observation.

Results. During five nights of observations, the system performed smoothly, and the observations of optical pulsar calibration targets provided excellent results.