Speaker
Description
In recent years, intensity interferometry has seen renewed interest and successful application at Imaging Atmospheric Cherenkov Telescope arrays such as H.E.S.S., MAGIC and VERITAS. However, these measurements can only be performed during bright moon periods while the instruments' primary purpose---gamma-ray observations---cannot be fulfilled, the Mobile Intensity Interferometer for Stellar Observations was designed as a proof of concept for a purpose-built intensity interferometer.
Using acrylic $1\,$m diameter $1.2\,$m focal length Fresnel lenses, a compact, cheap and lightweight design was realized. The detector fixture allows for translation in the z-axis to adjust for measurements at different wavelengths (and therefore focal points) as well as easy swapping of the detector in its entirety.
Both mobility and scalability in quantity of this design allow specific targeting of projected baselines and orientations based on the target. Particularly for potential binary systems, selective coverage of a target's u-v plane is essential to probing the characteristics accurately.
A first campaign demonstrated the capability of these Fresnel lens telescopes by measuring the spatial coherence curve of Arcturus ($\alpha$ Boo). In observation time of under $11\,$h, the angular diameter was measured to milliarcsecond precision in agreement with literature values.
