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40 results on '"Korkiakoski, Visa"'

1. The coronagraphic Modal Wavefront Sensor: a hybrid focal-plane sensor for the high-contrast imaging of circumstellar environments

Author

Wilby, Michael J., Keller, Christoph U., Snik, Frans, Korkiakoski, Visa, and Pietrow, Alexander G. M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The raw coronagraphic performance of current high-contrast imaging instruments is limited by the presence of a quasi-static speckle (QSS) background, resulting from instrumental non-common path errors (NCPEs). Rapid development of efficient speckle subtraction techniques in data reduction has enabled final contrasts of up to 10-6 to be obtained, however it remains preferable to eliminate the underlying NCPEs at the source. In this work we introduce the coronagraphic Modal Wavefront Sensor (cMWS), a new wavefront sensor suitable for real-time NCPE correction. This pupil-plane optic combines the apodizing phase plate coronagraph with a holographic modal wavefront sensor, to provide simultaneous coronagraphic imaging and focal-plane wavefront sensing using the science point spread function. We first characterise the baseline performance of the cMWS via idealised closed-loop simulations, showing that the sensor successfully recovers diffraction-limited coronagraph performance over an effective dynamic range of +/-2.5 radians root-mean-square (RMS) wavefront error within 2-10 iterations. We then present the results of initial on-sky testing at the William Herschel Telescope, and demonstrate that the sensor is able to retrieve injected wavefront aberrations to an accuracy of 10nm RMS under realistic seeing conditions. We also find that the cMWS is capable of real-time broadband measurement of atmospheric wavefront variance at a cadence of 50Hz across an uncorrected telescope sub-aperture. When combined with a suitable closed-loop adaptive optics system, the cMWS holds the potential to deliver an improvement in raw contrast of up to two orders of magnitude over the uncorrected QSS floor. Such a sensor would be eminently suitable for the direct imaging and spectroscopy of exoplanets with both existing and future instruments, including EPICS and METIS for the E-ELT., Comment: 14 pages, 12 figures: accepted for publication in Astronomy & Astrophysics

Published
2016
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2. Predictive learn and apply: MAVIS application - apply

Author

Cranney, Jesse, primary, Zhang, Hao, additional, Doucet, Nicolas, additional, Rigaut, François, additional, Gratadour, Damien, additional, Korkiakoski, Visa A., additional, De Dona, Jose, additional, Hong, Yuxi, additional, Ltaief, Hatem, additional, and Keyes, David E., additional

Published
2020
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3. MAVIS: science case, imager, and spectrograph

Author

Ellis, Simon C., primary, McDermid, Richard M., additional, Cresci, Giovanni, additional, Schwab, Christian, additional, Rigaut, François, additional, Chin, Timothy, additional, Content, Robert, additional, Horton, Anthony J., additional, Mohanan, Mahesh, additional, McGregor, Helen, additional, Pember, Jacob, additional, Robertson, David, additional, Waller, Lew, additional, Zhelem, Ross, additional, Monty, Stephanie, additional, Mendel, Trevor, additional, Aliverti, Matteo, additional, Agapito, Guido, additional, Antoniucci, Simone, additional, Balestra, Andrea, additional, Baruffolo, Andrea, additional, Bergomi, Maria, additional, Bianco, Andrea, additional, Bonaglia, Marco, additional, Bono, Guiseppe, additional, Bouret, Jean-Claude, additional, Brodrick, David, additional, Busoni, Lorenzo, additional, Carolo, Elena, additional, Chinellato, Simonetta, additional, Cranney, Jess, additional, de Silva, Gayandhi, additional, Esposito, Simone, additional, Fantinel, Daniela, additional, Farinato, Jacopo, additional, Fusco, Thierry, additional, Gausachs, Gaston, additional, Gilbert, James, additional, Gratadour, Damien, additional, Gerggio, Davide, additional, Gullieuszik, Marco, additional, Haguenauer, Pierre, additional, Haynes, Dionne M., additional, Korkiakoski, Visa, additional, Magrin, Demetrio, additional, Magrini, Laura, additional, Marafatto, Luca, additional, Neichel, Benoit, additional, Pedichini, Fernando, additional, Pinna, Enrico, additional, Plantet, Cedric, additional, Portaluri, Elisa, additional, Radhakrishnan Santhakumari, Kalyan K., additional, Ragazzoni, Roberto, additional, Salasnich, Bernado, additional, Ströbele, Stefan, additional, Thorn, Elliott, additional, Vaccarella, Annino, additional, Vassallo, Daniele, additional, Viotto, Valentina, additional, Zamkotsian, Frédéric, additional, Zanutta, Alessio, additional, and Zhang, Hao, additional

Published
2020
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4. MAVIS conceptual design

Author

Rigaut, François, primary, McDermid, Richard M., additional, Cresci, Giovanni, additional, Viotto, Valentina, additional, Ellis, Simon C., additional, Brodrick, David, additional, Agapito, Guido, additional, Fusco, Thierry, additional, Neichel, Benoit, additional, Haguenauer, Pierre, additional, Plantet, Cedric, additional, Salasnich, Bernardo, additional, Aliverti, Matteo, additional, Antoniucci, Simone, additional, Balestra, Andrea, additional, Baruffolo, Andrea, additional, Beltramo-Martin, Olivier, additional, Bergomi, Maria, additional, Blanco, Andrea, additional, Bonaglia, Marco, additional, Bono, Giuseppe, additional, Busoni, Lorenzo, additional, Carolo, Elena, additional, Chinellato, Simonetta, additional, Content, Robert, additional, Cranney, Jesse, additional, de Silva, Gayandhi, additional, Esposito, Simone, additional, Fantinel, Daniela, additional, Farinato, Jacopo, additional, Haynes, Dionne M., additional, Horton, Anthony J., additional, Gausachs, Gaston, additional, Gilbert, James, additional, Gratadour, Damien, additional, Greggio, Davide, additional, Gullieuszik, Marco, additional, Korkiakoski, Visa, additional, Magrin, Demetrio, additional, Magrini, Laura, additional, Marafatto, Luca, additional, McGregor, Helen, additional, Mendel, Trevor, additional, Monty, Stephanie, additional, Pedichini, Fernando, additional, Pinna, Enrico, additional, Portaluri, Elisa, additional, Radhakrishnan Santhakumari, Kalyan K., additional, Ragazzoni, Roberto, additional, Robertson, David, additional, Schwab, Christian, additional, Ströbele, Stefan, additional, Thorn, Elliott, additional, Vaccarella, Annino, additional, Vassallo, Daniele, additional, Waller, Lew, additional, Zamkotsian, Frédéric, additional, Zanutta, Alesso, additional, and Zhang, Hao, additional

Published
2020
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5. MAVIS Technical Budget - Phase A

Author

AGAPITO, Guido, VIOTTO, VALENTINA, PLANTET, Cedric Antoine Adrien Gabriel, GREGGIO, Davide, Zang, Hao, Gausachs, Gaston, Ellis, Simon, Schwab, Christian, Korkiakoski, Visa, Brodrick, David, AUS, David Brodrick, and Francois Rigaut

Published
2020

13. A conceptual design study for Subaru ULTIMATE GLAO

Author

Rigaut, François, primary, Minowa, Yosuke, primary, Akiyama, Masayuki, primary, Ono, Yoshito H., primary, Korkiakoski, Visa A., primary, Clergeon, Christophe S., primary, d'Orgeville, Celine, primary, Gausachs, Gaston, primary, Herrald, Nicholas, primary, Iwata, Ikuru, primary, Tanaka, Ichi, primary, Kodama, Tadayuki, primary, Hayano, Yutaka, primary, Motohara, Kentrao, primary, Davies, Jordan, primary, Hattori, Takashi, primary, Koyama, Yusei, primary, Yoshida, Michitoshi, primary, and Wang, Shiang-Yu, primary

Published
2018
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14. Adaptive optics tracking and pushing system for space debris manoeuvre

Author

Grosse, Doris, primary, Bennet, Francis, primary, Rigaut, François, primary, d'Orgeville, Céline, primary, Korkiakoski, Visa A., primary, Smith, Craig H., primary, Copeland, Michael, primary, Price, Ian, primary, Blundell, Mark, primary, Chan, Amy, primary, Ellis, Michael, primary, Galla, Antony, primary, Gers, Luke, primary, Hart, John, primary, Lingham, Marcus, primary, Gao, Yue, primary, Houston, Ellen, primary, Rees, Emily R., primary, Wang, Yanjie, primary, Ritchie, Ian, primary, Travouillon, Tony, primary, Vaccarella, Annino, primary, and Webb, James, primary

Published
2018
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16. An integrated identification and predictive control strategy for high wind velocity adaptive optics applications

Author

Close, L., Schreiber, L., Schmidt, D., Cranney, Jesse, De Dona, Jose, Korkiakoski, Visa, Rigaut, Francois, Close, L., Schreiber, L., Schmidt, D., Cranney, Jesse, De Dona, Jose, Korkiakoski, Visa, and Rigaut, Francois

Abstract

Adaptive Optics (AO) systems rely on atmospheric turbulence models in order to reduce the effect of wave-front aberrations on image quality. Due to the nature of turbulence, these models can exploit shift-invariant structures without a severe loss in generality. The resulting subset of possible state-matrices is efficiently characterised for identification using Quadratic Programming (QP). Additionally, the initial assumption of shift-invariance is relaxed in order to accommodate for the boundary effect of finite-pupils.

Published
2018

17. Rolling shutter detector data flow strategies to push the limits of AO performance

Author

Close, L., Schreiber, L., Schmidt, D., Dirnberger, Markus, Rigaut, Francois, Minowa, Yosuke, Conan, Rodolphe, Guyon, Olivier, Gratadour, Damien, Korkiakoski, Visa, Close, L., Schreiber, L., Schmidt, D., Dirnberger, Markus, Rigaut, Francois, Minowa, Yosuke, Conan, Rodolphe, Guyon, Olivier, Gratadour, Damien, and Korkiakoski, Visa

Abstract

Adaptive Optics (AO) improves the image quality of ground-based telescopes, by compensating in real-time for the blurring effects of atmospheric turbulence. AO systems of future Extremely Large Telescopes (ELTs) will have to operate at much bigger scales (in terms of degrees of freedom) and faster control rates (in terms of loop frequency) to realise their full potential. We have investigated and simulated an AO control methodology to stream pixels "as they come" using a rolling-shutter sCMOS camera to reconstruct 2D images. Compared to a traditional global shutter implementation, the initial results indicate the rolling shutter can reduce control loop latency by a factor of two to four, using existing hardware. This means we can detect twice the number of photons while sampling twice as slowly. Nevertheless, significant technical challenges remain in implementing the rolling functionality, especially when integrating off- The -shelf software and hardware, which is often constricted by a closed-source code base. Furthermore, as the rolling shutter readout is asynchronous, questions remain about coupling and aliasing of telescope vibrations into the imaging system, causing distortions of time and space. If successfully implemented in practice, the rolling shutter approach has the potential to allow astronomers and engineers to capture better scientific observations closer to the diffraction limit.

Published
2018

18. A conceptual design study for Subaru ULTIMATE GLAO

Author

Close, L., Schreiber, L., Schmidt, D., Rigaut, Francois, Minowa, Yosuke, Akiyama, Masayuki, Ono, Yoshito, Korkiakoski, Visa, Herrald, Nicholas, Gausachs, Gaston, Clergeon, Christophe, Wang, Shiang-Yu, d'Orgeville, Celine, Davies, J. A., Koyama, Yusei, Iwata, Ikuru, Kodama, Tadayuki, Motohara, Kentaro, Hayano, Yutaka, Tanaka, Ichi, Close, L., Schreiber, L., Schmidt, D., Rigaut, Francois, Minowa, Yosuke, Akiyama, Masayuki, Ono, Yoshito, Korkiakoski, Visa, Herrald, Nicholas, Gausachs, Gaston, Clergeon, Christophe, Wang, Shiang-Yu, d'Orgeville, Celine, Davies, J. A., Koyama, Yusei, Iwata, Ikuru, Kodama, Tadayuki, Motohara, Kentaro, Hayano, Yutaka, and Tanaka, Ichi

Abstract

We report on the conceptual design study done for the Ground Layer Adaptive Optics system of the ULTIMATE-Subaru project. This is an ambitious instrument project, providing GLAO correction in a square field of view of 14 arcmin on a side, aiming to deliver improved seeing at the near infrared wavelength. Its client instruments are an imager and multi-IFU spectrograph at Cassegrain and a Multi-Object spectrograph at Nasmyth. In this paper, we introduce the ULTIMATE-Subaru project overview and its science case and report the results of the GLAO performance prediction based on the numerical simulation and conceptual design of the wavefront sensor system

Published
2018

19. Adaptive optics tracking and pushing system for space debris manoeuvre

Author

Laird Close, Laura Schreiber, Dirk Schmidt, Lingham, Marcus, Grosse, Doris, Bennet, Francis, Blundell, Mark, Chan, Amy, Copeland, Michael, d'Orgeville, Celine, Ellis, Michael, Galla, Tony, Gao, Yue, Gers, Luke, Hart, John, Houston, Ellen, Korkiakoski, Visa, Price, Ian, Rees, Emily, Rigaut, Francois, Ritchie, Ian, Smith, Craig, Travouillon, Tony, Vaccarella, Annino, Wang, Yanjie, Webb, James, Laird Close, Laura Schreiber, Dirk Schmidt, Lingham, Marcus, Grosse, Doris, Bennet, Francis, Blundell, Mark, Chan, Amy, Copeland, Michael, d'Orgeville, Celine, Ellis, Michael, Galla, Tony, Gao, Yue, Gers, Luke, Hart, John, Houston, Ellen, Korkiakoski, Visa, Price, Ian, Rees, Emily, Rigaut, Francois, Ritchie, Ian, Smith, Craig, Travouillon, Tony, Vaccarella, Annino, Wang, Yanjie, and Webb, James

Abstract

As space debris in lower Earth orbits are accumulating, techniques to lower the risk of space debris collisions must be developed. Within the context of the Space Environment Research Centre (SERC), the Australian National University (ANU) is developing an adaptive optics system for tracking and pushing space debris. The strategy is to pre-condition a laser launched from a 1.8 m telescope operated by Electro Optics Systems (EOS) on Mount Stromlo, Canberra and direct it at an object to perturb its orbit. Current progress towards implementing this experiment, which will ensure automated operation between the telescope and the adaptive optics system, will be presented.

Published
2018

20. High level adaptive optics supervision software for fast transition to optimal performance

Author

Laird M. Close, Laura Schreiber, Dirk Schmidt, Korkiakoski, Visa, Rigaut, Francois, Price, Ian, Cranney, Jesse, Bennet, Francis, Lingham, Marcus, Grosse, Doris, Namjouyan, Nima, Copeland, Michael, d'Orgeville, Celine, Laird M. Close, Laura Schreiber, Dirk Schmidt, Korkiakoski, Visa, Rigaut, Francois, Price, Ian, Cranney, Jesse, Bennet, Francis, Lingham, Marcus, Grosse, Doris, Namjouyan, Nima, Copeland, Michael, and d'Orgeville, Celine

Abstract

Space debris in low Earth orbit (LEO) below 1500 km is becoming an increasing threat to spacecrafts. To manage the threat, we are developing systems to improve the ground-based tracking and imaging of space debris and satellites. We also intend to demonstrate that it is possible to launch a high-power laser that modifies the orbits of the debris. However, atmospheric turbulence makes it necessary to use adaptive optics with such systems. When engaging with objects in LEO, the objects are available only a limited amount of time. During the observation window, the object has to be acquired and performance of all adaptive optics feedback loops optimised. We have implemented a high-level adaptive optics supervision tool to automatise time-consuming tasks related to calibration and performance monitoring. This paper describes in detail the current features of our software.

Published
2018

21. Adaptive optics corrected imaging for satellite and debris characterisation

Author

Laird Close, Laura Schreiber, Dirk Schmidt, Copeland, Michael, Bennet, Francis, Rigaut, Francois, Korkiakoski, Visa, d'Orgeville, Celine, Smith, Craig, Laird Close, Laura Schreiber, Dirk Schmidt, Copeland, Michael, Bennet, Francis, Rigaut, Francois, Korkiakoski, Visa, d'Orgeville, Celine, and Smith, Craig

Abstract

We report on the design and initial laboratory testing of the Adaptive Optics Imaging (AOI) system. AOI has been developed by the Research School of Astronomy and Astrophysics (RSAA) at the Australian National University (ANU), in partnership with the Space Environment Research Centre (SERC), for imaging satellites and debris in low Earth orbit (LEO) and geostationary orbit (GEO). From AO corrected images we will resolve features greater than 50 cm allowing size, shape and orientation characterisation.

Published
2018

27. Designing and testing the coronagraphic Modal Wavefront Sensor: A fast non-common path error sensor for high-contrast imaging

Author

Wilby, M J, Keller, Christoph U, Haffert, S Y, Korkiakoski, Visa, Snik, Frans, Pietrow, A, Wilby, M J, Keller, Christoph U, Haffert, S Y, Korkiakoski, Visa, Snik, Frans, and Pietrow, A

Abstract

Non-Common Path Errors (NCPEs) are the dominant factor limiting the performance of current astronomical high-contrast imaging instruments. If uncorrected, the resulting quasi-static speckle noise floor limits coronagraph performance to a raw contrast of typically 10−4, a value which does not improve with increasing integration time. The coronagraphic Modal Wavefront Sensor (cMWS) is a hybrid phase optic which uses holographic PSF copies to supply focal-plane wavefront sensing information directly from the science camera, whilst maintaining a bias-free coronagraphic PSF. This concept has already been successfully implemented on-sky at the William Herschel Telescope (WHT), La Palma, demonstrating both real-time wavefront sensing capability and successful extraction of slowly varying wavefront errors under a dominant and rapidly changing atmospheric speckle foreground. In this work we present an overview of the development of the cMWS and recent first light results obtained using the Leiden EXoplanet Instrument (LEXI), a high-contrast imager and high-dispersion spectrograph pathfinder instrument for the WHT.

Published
2016

31. Adaptive optics tracking and pushing system for space debris manoeuvre

Author

Close, Laird M., Schreiber, Laura, Schmidt, Dirk, Lingham, Marcus, Grosse, Doris, Bennet, Francis, Blundell, Mark, Chan, Amy, Copeland, Michael, d'Orgeville, Celine, Ellis, Michael, Galla, Antony, Gao, Yue, Gers, Luke, Hart, John, Houston, Ellen, Korkiakoski, Visa, Price, Ian, Rees, Emily R., Rigaut, Francois, Ritchie, Ian, Smith, Craig, Travouillon, Tony, Vaccarella, Annino, Wang, Yanjie, and Webb, James

Published
2018
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40. A conceptual design study for Subaru ULTIMATE GLAO

Author

Close, Laird M., Schreiber, Laura, Schmidt, Dirk, Rigaut, François, Minowa, Yosuke, Akiyama, Masayuki, Ono, Yoshito, Korkiakoski, Visa, Herrald, Nick, Gausachs, Gaston, Clergeon, Christophe, Wang, Shiang-Yu, d'Orgeville, Céline, Davies, Jordan, Koyama, Yusei, Iwata, Ikuru, Kodama, Tadayuki, Motohara, Kentrao, Hayano, Yutaka, Tanaka, Ichi, Hattori, Takashi, and Yoshida, Michitoshi

Published
2018
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