Speaker
Description
This work investigates the feasibility of carrying out stellar photon-correlation measurements using the 1.3 m Devasthal Fast Optical Telescope (DFOT) at the ARIES Devasthal Observatory near Nainital, India. The experiment will use Becker & Hickl hybrid photodetectors in a two-detector Hanbury Brown–Twiss configuration. This detector system was previously used for photon-correlation measurements at the Calern Observatory in France and is now being adapted for observations with the DFOT.
The fast (f/4) beam of the DFOT cannot be coupled directly to the existing detector system. Dedicated adapter optics are therefore being developed to collimate the beam before narrowband filtering and division between the two detectors. Laboratory measurements are being performed to carry out the correlation measurements with the adapted system and validate the correlation data thus verifying the detection of photon bunching〖 (g〗^2 (τ)). A scaled pupil simulator is also being developed to reproduce the DFOT beam and central obstruction under laboratory conditions. Expected photon count rates, signal-to-noise ratios and required integration times are estimated for suitable target stars.
The planned campaign will initially focus on temporal intensity correlation with a single telescope. This work will provide a basis for future spatial-correlation measurements using two spatially separated telescopes. The results will determine the readiness of the system for the observing auto-correlation campaign planned at DFOT in February–March 2027.
