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Seminars at FGG

Very fast photometry, the road to Quantum Astronomy

Speaker: C. Barbieri and G. Naletto (University of Padova, Italy)

Date and time: 2013-11-25 11:30

With the aim to measure the statistics of arrival times of visible photons with a precision and accuracy much better than 1 nanosecond for hours of continuous observations, we have built two very fast photometers (Iqueye and Aqueye) based on SiliconSingle Photon Avalanche Photodiodes (SPADs). Both photometers share the optical solution of splitting the beam of light in 4 by a pyramid, each sub-beam feeding a separate SPAD. This solution has two advantages, to increase the overall count rate if the counts from each SPD are summed together, to allow simultaneous multicolour photometry if counts from the 4 channels are treated separately. Iqueye has been built for a 4-m class telescope and will be tried at the WHT the next nights. It has been used successfully at the NTT, obtaining excellent light curves of visible pulsars. The main aim of the forthcoming WHT run is acquisition of Giant Radio Bursts from the Crab pulsar simultaneous with radio observations by Westerbork and Jodrell Bank. Aqueye, built for the Asiago 1.8m telescope, is now upgraded with the addition of a coronagraphic module based on the Optical Vorticity imparted by a suitable phase mask, and of an adaptive optics module. If weather allows, Iqueye and Iqueye will take simultaneous optical data of the Crab pulsar. During our talk we will show some of the scientific results obtained so far, and technical details of the two instruments. In conclusion, we'll expand on future posssbile applications of extremely fast (picosecond) time resolution when the E-ELT and/or the CTA will be avialable. A first exciting possibility will be toresurrect the Intensity Interferometry of Hanbury Brownamong distant, not even optically linked, teleesocpes, such us the VLT and the E-ELT.