TY - GEN
T1 - Toward a diffraction-limited square-kilometer optical telescope: Digital revival of intensity interferometry - art. no. 698609
AU - Dravins, Dainis
AU - LeBohec, Stephan
PY - 2008
Y1 - 2008
N2 - Much of the progress in astronomy follows imaging with improved resolution. In observing stars, current capabilities are only marginal in beginning to image the disks of a few, although many stars will appear as surface objects for baselines of hundreds of meters. Since atmospheric turbulence makes ground-based phase interferometry challenging for such long baselines, kilometric space telescope clusters have been proposed for imaging stellar surface details. The realization of such projects remains uncertain, but comparable imaging could be realized by ground-based intensity interferometry. While insensitive to atmospheric turbulence and imperfections in telescope optics, the method requires large flux collectors, such as being set up as arrays of atmospheric Cherenkov telescopes for studying energetic gamma rays. High-speed detectors and digital signal handling enable very many baselines to be synthesized between pairs of telescopes, while stars may be tracked across the sky by electronic time delays. First observations with digitally combined optical instruments have now been made with pairs of 12-meter telescopes of the VERITAS array in Arizona. Observing at short wavelengths adds no problems, and similar techniques on an extremely large telescope could achieve diffraction-limited imaging down to the atmospheric cutoff, achieving a spatial resolution significantly superior by that feasible by adaptive optics operating in the red or near-infrared.
AB - Much of the progress in astronomy follows imaging with improved resolution. In observing stars, current capabilities are only marginal in beginning to image the disks of a few, although many stars will appear as surface objects for baselines of hundreds of meters. Since atmospheric turbulence makes ground-based phase interferometry challenging for such long baselines, kilometric space telescope clusters have been proposed for imaging stellar surface details. The realization of such projects remains uncertain, but comparable imaging could be realized by ground-based intensity interferometry. While insensitive to atmospheric turbulence and imperfections in telescope optics, the method requires large flux collectors, such as being set up as arrays of atmospheric Cherenkov telescopes for studying energetic gamma rays. High-speed detectors and digital signal handling enable very many baselines to be synthesized between pairs of telescopes, while stars may be tracked across the sky by electronic time delays. First observations with digitally combined optical instruments have now been made with pairs of 12-meter telescopes of the VERITAS array in Arizona. Observing at short wavelengths adds no problems, and similar techniques on an extremely large telescope could achieve diffraction-limited imaging down to the atmospheric cutoff, achieving a spatial resolution significantly superior by that feasible by adaptive optics operating in the red or near-infrared.
KW - stellar surface imaging
KW - astronomical intensity interferometry
KW - air Cherenkov telescopes
KW - quantum optics
U2 - 10.1117/12.801260
DO - 10.1117/12.801260
M3 - Paper in conference proceeding
VL - 6986
SP - 98609
EP - 98609
BT - Extremely Large Telescopes: Which Wavelengths? Retirement Symposium for Arne Ardeberg
PB - SPIE
T2 - Retirement Symposium for Arne Ardeberg on Extremely Large Telescopes - Which Wavelengths
Y2 - 29 November 2007 through 30 November 2007
ER -