Dr. Ramya M. Anche Profile

Dr. Ramya M. Anche

Postdoctoral Research Associate at University of Arizona

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Author

Publications (21)

Proceedings Article | 18 July 2024 Poster + Paper

Investigating the polarimetric capabilities for the Giant Magellan Telescope

Hill Tailor, Ramya Anche, G. Grant Williams, John Piotrowski, Daewook Kim

Proceedings Volume 13096, 1309648 (2024) https://doi.org/10.1117/12.3020667

KEYWORDS: Polarimetry, Telescopes, Equipment, Image quality, Polarization, Design, Cameras, Lenses, Prisms, Optical design

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Proceedings Article | 18 July 2024 Poster + Paper

Systems design, assembly, integration, and lab testing of WALOP-South Polarimeter

Siddharth Maharana, A. Ramaprakash, Chaitanya Rajarshi, Pravin Khodade, Bhushan Joshi, Pravin Chordia, Abhay Kohok, Ramya Anche, Deepa Modi, John Kypriotakis, Amit Deokar, Aditya Kinjawadekar, Stephen Potter, Dmitry Blinov, Hans Kristian Eriksen, Myrto Falalaki, Hitesh Gajjar, Tuhin Ghosh, Eirik Gjerløw, Sebastian Kiehlmann, Ioannis Liodakis, Nikolaos Mandarakas, Georgia Panopoulou, Vasiliki Pavlidou, Timothy Pearson, Vincent Pelgrims, Anthony C. Readhead, Raphael Skalidis, Konstantinos Tassis, Namita Uppal, Ingunn Wehus

Proceedings Volume 13096, 130967P (2024) https://doi.org/10.1117/12.3016144

KEYWORDS: Equipment, Cameras, Polarimetry, Polarizers, Collimators, Telescopes, Cements, Polarization, Calibration, Optomechanical design, Optical design, Calcite

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Wide-Area Linear Optical Polarimeter (WALOP)-South is the first wide-field and survey-capacity polarimeter in the optical wavelengths. On schedule for commissioning in 2024, it will be mounted on the 1 m SAAO telescope in Sutherland Observatory, South Africa to undertake the PASIPHAE sky survey. PASIPHAE program will create the first polarimetric sky map in the optical wavelengths, spanning more than 2000 square degrees of the southern Galactic region. In a single exposure, WALOP-South’s innovative design will enable it to measure the linear polarization (Stokes parameters q and u) of all sources in a field of view (FoV) of 35 × 35 arc-minutes-squared in the SDSS-r broadband and narrowband filters between 500-750 nm with 0.1 % polarization accuracy. The unique goals of the instrument place very stringent systems engineering goals, including on the performance of the optical, polarimetric, optomechanical, and electronic subsystems. In particular, the major technical hurdles for the project included the development of: (a) an optical design to achieve imaging quality PSFs across the FoV, (b) an optomechanical design to obtain high accuracy optical alignment in conjugation with minimal instrument flexure and stress birefringence on optics (which can lead to variable instrumental polarization), and (c) an on-sky calibration routine to remove the strong polarimetric cross-talk induced instrumental polarization to obtain 0.1% across the FoV. All the subsystems have been designed carefully to meet the overall instrument performance goals. As of May 2024, all the instrument optical and mechanical subsystems have been assembled and are currently getting tested and integrated. The complete testing and characterization of the instrument in the lab is expected to be completed by August 2024. While the instrument was initially scheduled for commissioning in 2022, it got delayed due to various technical challenges; WALOP-South is now on schedule for commissioning in second half of 2024. In this paper, we will present (a) the design and development of the entire instrument and its major subsystems, focusing the instrument’s opto-mechanical design which has not been reported before, and (b) assembly and integration of the instrument in the lab and early results from lab characterization of the instrument’s optical performance.

Proceedings Article | 18 July 2024 Presentation + Paper

SHARK-NIR commissioning and early science runs

Domenico Barbato, Jacopo Farinato, Andrea Baruffolo, Maria Bergomi, Andrea Bianco, Federico Biondi, Florian Briegel, Elena Carolo, Paolo Cerpelloni, Alexis Carlotti, Simonetta Chinellato, Albert Conrad, Marco De Pascale, Simone Di Filippo, Marco Dima, Valentina D'Orazi, Steve Ertel, Tania Sofia Gomes Machado, Davide Greggio, Juan Carlos Guerra, Thomas Henning, Justin Hom, John Hill, Fulvio Laudisio, Luigi Lessio, Alessandro Lorenzetto, Demetrio Magrin, Luca Marafatto, Dino Mesa, Doug Miller, Lars Mohr, Manny Montoya, Jennifer Power, Kalyan Radhakrishnan, Davide Ricci, Gabriele Umbriaco, Daniele Vassallo, Valentina Viotto, Greg Taylor, Alessio Zanutta, Ramya Anche, Simone Antoniucci, Carmelo Arcidiacono, Francesca Bacciotti, Pierre Baudoz, Angela Bongiorno, Laird Close, Simone Esposito, Paul Grenz, Olivier Guyon, Jarron Leisenring, Fernando Pedichini, Roberto Piazzesi, Enrico Pinna, Elisa Portaluri, Alfio Puglisi, Roberto Ragazzoni, Gabriele Rodeghiero, Fabio Rossi, Joseph Shields, Macarena Vega Pallauda

Proceedings Volume 13096, 130961W (2024) https://doi.org/10.1117/12.3020068

KEYWORDS: Stars, Coronagraphy, Equipment, Telescopes, Adaptive optics, Cameras

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SHARK-NIR is an instrument providing high-contrast coronagraphic imaging, dual band imaging and low resolution spectroscopy in Y, J and H bands, taking advantage of the high performance of the Large Binocular Telescope (LBT) AO systems. Its main scientific drivers is the detection and characterization of exoplanets, circumstellar disks, Solar System small bodies and acrive galactic nuclei. Binocular observations are provided by exploiting the synergy with SHARK-VIS (operating in V band) and LMIRCam of LBTI (operating from K to M band). SHARK-NIR was shipped to LBT in June 2022, and up to November 2022 was the subject of the three pre-commissioning runs: the first to install and test the instrument in the high-bay LBT clean tent, the second to install and align the instrument to the telescope and the third to perform daytime testing. This pre-commissioning phase resulted in the successful alignment of the instrument with a very good internal optical quality and the performance of additional tests using simulated turbulence injected through LBT Adaptive Secondary Mirror. In January 2023 we had the first commissioning run and the instrument first light, in which we successfully tested the imaging capabilities with and without the Gaussian Lyot coronagraph. In March 2023 we had the second commissioning run, in which despite the bad weather we successfully performed a variety of technical activities, as well as preliminary testing of the Shaped Pupil coronagraph. After two additional commissioning runs in May and October, our first early scientific run in October 2023 focused on the Taurus star formation region, a region populated by targets of considerable scientific interest. In this paper we will give an overview of commissioning and the early science phases running from October 2023 to May 2024, focusing on the technical challenges we overcame and future work needed to push the instrument to its very limit, as well as presenting the first preliminary scientific results.

Proceedings Article | 5 October 2023 Poster + Paper

NMF-based GPU accelerated coronagraphy pipeline

Sai Krishanth P. M., Ewan Douglas, Justin Hom, Ramya Anche, John Debes, Isabel Rebollido, Bin Ren

Proceedings Volume 12680, 1268021 (2023) https://doi.org/10.1117/12.2677739

KEYWORDS: Point spread functions, Stars, Signal to noise ratio, Coronagraphy, Matrices, James Webb Space Telescope, Space telescopes

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Proceedings Article | 5 October 2023 Presentation + Paper

Estimation of polarization aberrations and their effect on the coronagraphic performance for future space telescopes

Ramya Anche, Sebastiaan Haffert, Jaren Ashcraft, Kian Milani, Kyle Van Gorkom, Kevin Derby, Ewan Douglas, Maxwell Millar-Blanchaer

Proceedings Volume 12680, 126800R (2023) https://doi.org/10.1117/12.2677486

KEYWORDS: Coating, Coronagraphy, Polarization, Telescopes, Mirrors, Reflection, Polarization analysis

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Proceedings Article | 4 October 2023 Paper

Approaches to lowering the cost of large space telescopes

Ewan Douglas, Greg Aldering, Greg Allan, Ramya Anche, Roger Angel, Cameron Ard, Supriya Chakrabarti, Laird Close, Kevin Derby, Jerry Edelstein, John Ford, Jessica Gersh-Range, Sebastiaan Haffert, Patrick Ingraham, Hyukmo Kang, Douglas Kelly, Daewook Kim, Michael Lesser, Jarron Leisenring, Yu-Chia Lin, Jared Males, Buddy Martin, Bianca Alondra Payan, Sai Krishanth P. M., David Rubin, Sanford Selznick, Kyle Van Gorkom, Buell Jannuzi, Saul Perlmutter

Proceedings Volume 12677, 126770D (2023) https://doi.org/10.1117/12.2677843

KEYWORDS: Space telescopes, Design and modelling, Telescopes, Observatories, Mirrors, James Webb Space Telescope, Space mirrors, Equipment, Astronomy, Coronagraphy

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Proceedings Article | 3 October 2023 Presentation + Paper

Polarimetric modeling and assessment of science cases for Giant Magellan Telescope-Polarimeter (GMT-Pol)

Ramya Anche, Grant Williams, Hill Tailor, Chris Packham, Daewook Kim, Jaren Ashcraft, Ewan Douglas

Proceedings Volume 12690, 126900F (2023) https://doi.org/10.1117/12.2676777

KEYWORDS: Polarization, Polarimetry, Telescopes, Crosstalk, Modeling, Mirrors, Design and modelling, Spectrographs, Polarization analysis

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Proceedings Article | 28 September 2023 Presentation + Paper

Poke: an open-source, ray-based physical optics platform

Jaren Ashcraft, Ewan Douglas, Daewook Kim, A. J. Riggs, Ramya Anche, Trent Brendel, Kevin Derby, Brandon Dube, Quinn Jarecki, Emory Jenkins, Kian Milani

Proceedings Volume 12664, 1266404 (2023) https://doi.org/10.1117/12.2678001

KEYWORDS: Ray tracing, Polarization, Diffraction, Modeling, Thin films, Interfaces, Simulations, Design and modelling, Wavefronts, Telescopes

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Proceedings Article | 29 August 2022 Presentation + Paper

Stress-induced birefringence in the lenses of Wide-Area Linear Optical Polarimeter-South

Ramya M. Anche, Siddharth Maharana, A. N. Ramaprakash, Pravin Khodade, Deepa Modi, Chaitanya Rajarshi, John A. Kypriotakis, Dmitry Blinov, Hans Kristian Eriksen, Tuhin Ghosh, Georgia V. Panopoulou, Vincent Pelgrims, Raphael Skalidis, Timothy J. Pearson, Eirik Gjerløw, Nikolaos Mandarakas, Vasiliki Pavlidou, Stephen B. Potter, Anthony C. S. Readhead, Konstantinos Tassis, Artem Basyrov, Katerina Papadaki, Trygve Leithe Svalheim, Ingunn K. Wehus

Proceedings Volume 12188, 121882C (2022) https://doi.org/10.1117/12.2629515

KEYWORDS: Birefringence, Polarization, Polarimetry, Telescopes, Finite element methods

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Two unique wide-field and high-accuracy polarimeters named WALOP (Wide-Area Linear Optical Polarimeter)- North and WALOP-South are currently under development at the Inter-University Center for Astronomy and Astrophysics (IUCAA), India, to create a large area optical polarization map of the sky for the upcoming PASIPHAE sky survey. These instruments are designed to achieve a linear polarimetric measurement accuracy of 0.1% across a field of view (FoV) of 30×30 arcminutes. The WALOP-South instrument will be installed first on a 1 m telescope at the Sutherland Observatory, where the temperatures during the night can vary between 10 to -5°C. These temperature variations and the instrument’s pointing to various non-zenithal positions in the sky can introduce stress birefringence in the lenses, leading to time-varying instrumental polarization. This work estimates stress-induced birefringence due to thermal, and gravity stresses on WALOP-South lenses. Using the optomechanical model of the WALOP-South, we carried out Finite Element Analysis (FEA) simulations in SolidWorks software to estimate the stresses for various scenarios of temperature, telescope pointing airmass, and lens mount material (aluminum and titanium). Further, we use the stress tensor analysis to estimate the principal stresses and their directions and consequent birefringence and retardance introduced in the lenses. The stressinduced birefringence will change the optical path length for orthogonal polarization states of the beam passing through the lenses and introduce phase retardation. Overall, with the lens mount design of the instrument, we find that the retardation and consequent instrumental polarization will be within the instrumental accuracy requirements. Additionally, the stress birefringence is found to be higher for aluminum compared to titanium mounts. We further incorporated this retardance in the instrument Mueller matrix estimation to understand its effects on the polarization measurements.

Proceedings Article | 29 August 2022 Poster + Paper

The polarization aberrations of the Gemini Telescope as seen by the Gemini Planet Imager

Maxwell Millar-Blanchaer, Ramya Anche, Meiji M. Nguyen, Jérôme Maire

Proceedings Volume 12184, 121843X (2022) https://doi.org/10.1117/12.2629524

KEYWORDS: Polarization, Gemini Planet Imager, Data modeling, Mirrors, Polarimetry, Gemini Observatory, Telescopes, Coronagraphy, Atmospheric modeling, Planets, Adaptive optics, High angular resolution imaging

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Proceedings Article | 27 August 2022 Poster + Paper

The space coronagraph optical bench (SCoOB): 1. Design and assembly of a vacuum-compatible coronagraph testbed for spaceborne high-contrast imaging technology

Jaren Ashcraft, Heejoo Choi, Ewan Douglas, Kevin Derby, Kyle Van Gorkom, Daewook Kim, Ramya Anche, Alex Carter, Olivier Durney, Sebastiaan Haffert, Lori Harrison, Maggie Kautz, Jennifer Lumbres, Jared Males, Kian Milani, Oscar Montoya, George Smith

Proceedings Volume 12180, 121805L (2022) https://doi.org/10.1117/12.2628855

KEYWORDS: Coronagraphy, Wavefronts, Mirrors, Interferometers, Wavefront sensors, Point spread functions, Optical benches, Cameras, Astronomical imaging

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Proceedings Article | 27 August 2022 Poster + Paper

Simulations of polarimetric observations of debris disks through the Roman Coronagraph Instrument

Ramya Anche, Ewan Douglas, Kian Milani, Jaren Ashcraft, John Debes

Proceedings Volume 12180, 1218056 (2022) https://doi.org/10.1117/12.2629497

KEYWORDS: Polarization, Mathematical modeling, Polarimetry, Point spread functions, Coronagraphy, Light scattering, Electron multiplying charge coupled devices, Device simulation

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Proceedings Article | 27 August 2022 Poster + Paper

The space coronagraph optical bench (SCoOB): 2. Wavefront sensing and control in a vacuum-compatible coronagraph testbed for spaceborne high-contrast imaging technology

Kyle Van Gorkom, Ewan Douglas, Jaren Ashcraft, Sebastiaan Haffert, Daewook Kim, Heejoo Choi, Ramya Anche, Jared Males, Kian Milani, Kevin Derby, Lori Harrison, Olivier Durney

Proceedings Volume 12180, 121805M (2022) https://doi.org/10.1117/12.2630704

KEYWORDS: Coronagraphy, Wavefronts, Wavefront sensors, Actuators, Optical benches, Astronomical imaging, Cameras, Point spread functions, Imaging technologies, Light scattering

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SPIE Journal Paper | 9 March 2021

WALOP-South: a four-camera one-shot imaging polarimeter for PASIPHAE survey. Paper I—optical design

Siddharth Maharana, John Kypriotakis, Anamparambu Ramaprakash, Chaitanya Rajarshi, Ramya Anche, Shrish Shrish, Dmitry Blinov, Hans Eriksen, Tuhin Ghosh, Eirik Gjerløw, Nikolaos Mandarakas, Georgia Panopoulou, Vasiliki Pavlidou, Timothy Pearson, Vincent Pelgrims, Stephen Potter, Anthony C. Readhead, Raphael Skalidis, Konstantinos Tassis, Ingunn Wehus

JATIS, Vol. 7, Issue 01, 014004, (March 2021) https://doi.org/10.1117/12.10.1117/1.JATIS.7.1.014004

KEYWORDS: Polarimetry, Polarization, Sensors, Telescopes, Cameras, Prisms, Point spread functions, Optical design, Optical filters, Stars

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Proceedings Article | 13 December 2020 Poster + Paper

Polarization model for the multi-application solar telescope at the Udaipur Solar Observatory

Ramya Anche, M. Ranganathan, Shibu Mathew, K. Sankarasubramanian, G. Anupama, Bireddy Ramya, Avijeet Prasad, Rahul Yadav, Raja Bayanna

Proceedings Volume 11451, 114514O (2020) https://doi.org/10.1117/12.2561217

KEYWORDS: Polarization, Telescopes, Mirrors, Observatories, Polarimetry, Magnetism, Solar processes, Reflection, Reflector telescopes, Instrument modeling

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Proceedings Article | 13 December 2020 Poster + Presentation + Paper

WALOP-South: A wide-field one-shot linear optical polarimeter for PASIPHAE survey

Siddharth Maharana, John Kypriotakis, A. Ramaprakash, Pravin Khodade, Chaitanya Rajarshi, Bhushan Joshi, Pravin Chordia, Ramya Anche, Shrish Mishra, Dmitry Blinov, Hans Kristian Eriksen, Tuhin Ghosh, Eirik Gjerløw, Nikolaos Mandarakas, Georgia Panopoulou, Vasiliki Pavlidou, Timothy Pearson, Vincent Pelgrims, Stephen Potter, Anthony C. Readhead, Raphail Skalidis, Konstantinos Tassis, Ingunn Wehus

Proceedings Volume 11447, 114475E (2020) https://doi.org/10.1117/12.2554396

KEYWORDS: Polarimetry, Polarization, Telescopes, Stars, Astronomy, Optical filters, Photometry, Prisms, Vignetting, Optomechanical design

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Proceedings Article | 11 July 2018 Paper

The estimation of the instrumental polarization and crosstalk at the focus of the mid-infrared imaging system for the Thirty Meter Telescope

Ramya Anche, Chris Packham, G. C. Anupama, K. Sankarasubramanian, Maheswar Gopinathan, Manoj Puravankara

Proceedings Volume 10702, 1070298 (2018) https://doi.org/10.1117/12.2312558

KEYWORDS: Polarization, Mirrors, Telescopes, Imaging systems, Mid-IR, Polarimetry, Thirty Meter Telescope, Optical coatings, Modulators

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Proceedings Article | 11 July 2018 Paper

Estimation of polarization aberrations and its effect on the point spread function of the Thirty Meter Telescope

Ramya Anche, G. C. Anupama, S. Sriram, K. Sankarasubramanian, Warren Skidmore

Proceedings Volume 10703, 107034K (2018) https://doi.org/10.1117/12.2312506

KEYWORDS: Mirrors, Polarization, Point spread functions, Telescopes, Coating, Thirty Meter Telescope, Adaptive optics, Monochromatic aberrations, Zemax, Reflection

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SPIE Journal Paper | 22 January 2018

Analysis of polarization introduced due to the telescope optics of the Thirty Meter Telescope

Ramya Manjunath Anche, Asoke Kumar Sen, Gadiyara Chakrapani Anupama, Kasiviswanathan Sankarasubramanian, Warren Skidmore

JATIS, Vol. 4, Issue 01, 018003, (January 2018) https://doi.org/10.1117/12.10.1117/1.JATIS.4.1.018003

KEYWORDS: Mirrors, Polarization, Telescopes, Thirty Meter Telescope, Reflection, Polarimetry, Ray tracing, Calibration, Error analysis, Silver

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Proceedings Article | 15 June 2015 Paper

Analytical modelling of Thirty Meter Telescope optics polarization

Ramya Anche, G. Anupama, Krishna Reddy, Asoke Sen, K. Sankarasubramanian, A. Ramaprakash, Sujan Sengupta, Warren Skidmore, Jenny Atwood, Sivarani Tirupathi, Shashi Bhushan Pandey

Proceedings Volume 9654, 965408 (2015) https://doi.org/10.1117/12.2181397

KEYWORDS: Mirrors, Polarization, Telescopes, Zemax, Modeling, Instrument modeling, Mueller matrices, Polarimetry, Coating, Thirty Meter Telescope

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Proceedings Article | 4 August 2014 Paper

Polarimetric analysis of the Thirty Meter Telescope (TMT) for modeling instrumental polarization characteristics

Jenny Atwood, Warren Skidmore, G. Anupama, Ramya Anche, Krishna Reddy, Asoke Sen

Proceedings Volume 9150, 915013 (2014) https://doi.org/10.1117/12.2056965

KEYWORDS: Polarization, Polarimetry, Telescopes, Instrument modeling, Zemax, Coating, Adaptive optics, Systems modeling, Stars, Thirty Meter Telescope

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Showing 5 of 21 publications

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