Precision measurement of optical pulsation using a Cherenkov telescope

Hinton, J. A.; Hermann, G.; Krötz, Peter; Funk, S.

doi:10.1016/j.astropartphys.2006.04.008

Cited by 17 publications

(23 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have built an optical photometer (similar to the one described in [9]) and installed it on the H.E.S.S. telescope CT4 in January and May 2007 (see Figures 1 and 2).…”

Section: The Hess Cherenkov Telescopesmentioning

confidence: 99%

Microsecond Time Resolution Optical Photometry using a H.E.S.S. Cherenkov Telescope

Deil

Domainko

Hermann

2008

AIP Conference Proceedings

View full text Add to dashboard Cite

We have constructed an optical photometer with microsecond time resolution, which is currently being operated on one of the H.E.S.S. telescopes. H.E.S.S. is an array of four Cherenkov telescopes, each with a 107 m^ mirror, located in the Khomas highland in Namibia. In its normal mode of operation H.E.S.S. observes Cherenkov light from air showers generated by very high energy gamma-rays in the upper atmosphere. Our detector consists of seven photomultipliers, one in the center to record the lightcurve from the target and six concentric photomultipliers as a veto system to reject disturbing signals e.g. from meteorites or lightning at the horizon. The data acquisition system has been designed to continuously record the signals with zero deadtime. The Crab pulsar has been observed to verify the performance of the instrument and the GPS timing system. Compact galactic targets were observed to search for flares on timescales of a few microseconds to -^ 100 ms. The design and sensitivity of the instrument as well as the data analysis method are presented. Keywords: Ultrafast optical photometry, Cherenkov telescope PACS: 95.55.Ka, 95.55.Qf 95.75.Wx, 97.80.Jp

show abstract

“…We have built an optical photometer (similar to the one described in [9]) and installed it on the H.E.S.S. telescope CT4 in January and May 2007 (see Figures 1 and 2).…”

Section: The Hess Cherenkov Telescopesmentioning

confidence: 99%

Microsecond Time Resolution Optical Photometry using a H.E.S.S. Cherenkov Telescope

Deil

Domainko

Hermann

2008

AIP Conference Proceedings

View full text Add to dashboard Cite

show abstract

“…Of course, it will mainly be devoted to its primary task of observing Cherenkov light in air; however several other applications have been envisioned, to be preferably carried out during nights with bright moonlight which -owing to the faintness of the Cherenkov light flashes -might preclude their efficient observation. Besides intensity interferometry (Dravins et al, 2013), additional uses that have been suggested include searches for rapid astrophysical events (Deil et al, 2009;Hinton et al, 2006;Lacki, 2011), observations of stellar occultations by distant Kuiper-belt objects (Lacki, 2014), or as a terrestrial ground station for optical communication with distant spacecraft (Carrasco-Casado et al, 2013). For practical operations, one proposed concept is to place auxiliary detectors on the outside of the Cherenkov camera cover lid, an approach already realized on some telescopes (Deil et al, 2009;Hinton et al, 2006), and one that should not interfere with regular Cherenkov camera operations.…”

Section: Principles Of Intensity Interferometrymentioning

confidence: 99%

Long-baseline optical intensity interferometry

Dravins

Lagadec

Nuñez

2015

A&A

View full text Add to dashboard Cite

Context. A long-held vision has been to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, and reveal interacting gas flows in binary systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and also used for intensity interferometry. Second-order spatial coherence of light is obtained by cross correlating intensity fluctuations measured in different pairs of telescopes. With no optical links between them, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are approximately one meter, making the method practically immune to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Aims. Previous theoretical modeling has shown that full images should be possible to retrieve from observations with such telescope arrays. This project aims at verifying diffraction-limited imaging experimentally with groups of detached and independent optical telescopes. Methods. In a large optics laboratory, artificial stars (single and double, round and elliptic) were observed by an array of small telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations were cross-correlated over up to 180 baselines between pairs of telescopes, producing coherence maps across the interferometric Fourier-transform plane. Results. These interferometric measurements were used to extract parameters about the simulated stars, and to reconstruct their twodimensional images. As far as we are aware, these are the first diffraction-limited images obtained from an optical array only linked by electronic software, with no optical connections between the telescopes. Conclusions. These experiments serve to verify the concepts for long-baseline aperture synthesis in the optical (somewhat analogous to radio interferometry) and to optimize the instrumentation and observing procedures for future observations with large arrays of Cherenkov telescopes, aiming at order-of-magnitude improvements of the angular resolution in optical astronomy.

show abstract

“…Of course, it will mainly be devoted to its main task of observing Cherenkov light in air; however several other applications have been envisioned, preferably to be carried out during nights with bright moonlight which  due to the faintness of the Cherenkov light flashes  might preclude their efficient observation. Besides intensity interferometry 4 , suggested additional uses include searches for rapid astrophysical events [14][15][16] , observing stellar occultations by distant Kuiper-belt objects 17 or as a terrestrial ground station for optical communication with distant spacecraft 18 . For practical operations, one proposed concept is to place auxiliary detectors on the outside of the Cherenkov camera cover lid, an approach already realized on some Cherenkov telescopes [14][15] , and one which should not interfere with regular Cherenkov camera operations.…”

Section: The Potential Of Air Cherenkov Telescopesmentioning

confidence: 99%

“…Besides intensity interferometry 4 , suggested additional uses include searches for rapid astrophysical events [14][15][16] , observing stellar occultations by distant Kuiper-belt objects 17 or as a terrestrial ground station for optical communication with distant spacecraft 18 . For practical operations, one proposed concept is to place auxiliary detectors on the outside of the Cherenkov camera cover lid, an approach already realized on some Cherenkov telescopes [14][15] , and one which should not interfere with regular Cherenkov camera operations. This potential of using Cherenkov telescope arrays for optical intensity interferometry has indeed been noticed by several [19][20] .…”

Section: The Potential Of Air Cherenkov Telescopesmentioning

confidence: 99%

Stellar intensity interferometry over kilometer baselines: laboratory simulation of observations with the Cherenkov Telescope Array

Dravins¹,

Lagadec²

2014

SPIE Proceedings

View full text Add to dashboard Cite

A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal interactions of stellar winds and gas flows in binary star systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and used also for intensity interferometry. With no optical connection between the telescopes, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are on the order of one meter, making the method practically insensitive to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Theoretical modeling has shown how stellar surface images can be retrieved from such observations and here we report on experimental simulations. In an optical laboratory, artificial stars (single and double, round and elliptic) are observed by an array of telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations are cross correlated between up to a hundred baselines between pairs of telescopes, producing maps of the second-order spatial coherence across the interferometric Fourier-transform plane. These experiments serve to verify the concepts and to optimize the instrumentation and observing procedures for future observations with (in particular) CTA, the Cherenkov Telescope Array, aiming at order-of-magnitude improvements of the angular resolution in optical astronomy.

show abstract

Precision measurement of optical pulsation using a Cherenkov telescope

Cited by 17 publications

References 21 publications

Microsecond Time Resolution Optical Photometry using a H.E.S.S. Cherenkov Telescope

Microsecond Time Resolution Optical Photometry using a H.E.S.S. Cherenkov Telescope

Long-baseline optical intensity interferometry

Stellar intensity interferometry over kilometer baselines: laboratory simulation of observations with the Cherenkov Telescope Array

Contact Info

Product

Resources

About