Mr. Hitesh Gajjar Profile

Hitesh Gajjar

at South African Astronomical Observatory

SPIE Involvement:

Author

Publications (19)

Proceedings Article | 18 July 2024 Poster + Paper

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

Read Abstract +

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 Poster + Paper

Poster + Paper

Instrumentation at the SAAO for autonomous rapid-response observing

Nicolas Erasmus, Stephen Potter, Carel H.D. van Gend, Egan Loubser, Kathryn Rosie, Keegan Titus, Sunil Chandra, Hannah Worters, Hitesh Gajjar, Moloko Hlakola, Roufurd Julie

Proceedings Volume 13096, 130968K (2024) https://doi.org/10.1117/12.3015250

KEYWORDS: Equipment, Telescopes, Observatories, Cameras, Imaging systems, Spectrographs

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SPIE Journal Paper | 27 April 2024

Mookodi: multi-purpose low-resolution spectrograph and multi-filter photometric imager for rapid follow-up observations of astronomical transient events

Nicolas Erasmus, Iain Steele, Andrzej Piascik, Stuart Bates, Christopher Mottram, Kathryn Rosie, Carel H. D. van Gend, Ulrich Geen, Magaretha L. Pretorius, Stephen Potter, Egan Loubser, Willie Koorts, Hitesh Gajjar, Keegan Titus, Hannah Worters, Amanda Sickafoose, Sunil Chandra, James E. O’Connor, Kgothatso Matlala, Justine Crook-Mansour, Ali Ranjbar, Robert Smith, Helen Jermak, Shalom Abiodun, Okwudili Egbo

JATIS, Vol. 10, Issue 02, 025005, (April 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.2.025005

KEYWORDS: Telescopes, Equipment, Spectrographs, Tunable filters, Cameras, Stars, Imaging systems, Sensors, Optical filters, Observatories

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Proceedings Article | 13 December 2020 Presentation + Paper

Presentation + Paper

Design of telescope and instrument control and interface software at the South African Astronomical Observatory: building blocks of the intelligent observatory

Carel H. D. van Gend, Amanda Sickafoose, Stephen Potter, Briehan Lombaard, Pieter Swanevelder, Hitesh Gajjar, Hannah Worters, Willie Koorts, Keegan Titus, Craig Sass, Egan Loubser, Nicolas Erasmus, James O'Connor, Ramotholo Sefako, Roufurd Julie, Freya Bovim

Proceedings Volume 11452, 1145206 (2020) https://doi.org/10.1117/12.2562161

KEYWORDS: Telescopes, Observatories, Astronomical telescopes, Astronomy, Optical instrument design, Control systems, Software development, Computer architecture, Large telescopes, Cameras

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Proceedings Article | 10 July 2018 Presentation + Paper

Presentation + Paper

Deskilling SALT primary mirror recoating process

Jonathan Love, Johannes Coetzee, Hitesh Gajjar, Martin Wilkinson

Proceedings Volume 10704, 1070425 (2018) https://doi.org/10.1117/12.2311603

KEYWORDS: Mirrors, Coating, Telescopes

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Proceedings Article | 6 July 2018 Presentation + Paper

Presentation + Paper

Designing an effective SALT building management system (BMS)

Paul Rabe, Keith R. Browne, Eben Wiid, Jonathan Love, Janus Brink, Hitesh Gajjar, J. Christiaan Coetzee, Martin Wilkinson

Proceedings Volume 10700, 1070006 (2018) https://doi.org/10.1117/12.2311602

KEYWORDS: Photonic integrated circuits, Software development, LabVIEW, Telecommunications, Control systems, Telescopes, Information operations, Computer aided design, Human-machine interfaces, Logic

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Proceedings Article | 6 July 2018 Paper

Paper

Design and results for the SAAO wide-field nasmyth camera

Pieter Swanevelder, Dave Carter, James O'Connor, Hannah Worters, Willie Koorts, Briehan Lombaard, Egan Loubser, Keegan Titus, Carel van Gend, Michael Rust, Craig Sass, Hitesh Gajjar, Amanda Sickafoose, A. N. Ramaprakash, Pravin Chordia, Mahesh Burse, Sujit Punnadi, Bhushan Joshi, Sakya Sinha

Proceedings Volume 10702, 107022K (2018) https://doi.org/10.1117/12.2312540

KEYWORDS: Camera shutters, Charge-coupled devices, Cameras, Telescopes, Astronomy

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Proceedings Article | 8 August 2016 Paper

Paper

SALT: Active control of the primary mirror with inductive edge sensors

Hitesh Gajjar, John Menzies, David Buckley, Chris Coetzee, Deon Bester, Ockert Strydom, Jonathan Love, Keith Browne

Proceedings Volume 9906, 990639 (2016) https://doi.org/10.1117/12.2234264

KEYWORDS: Sensors, Telescopes, Mirrors, Environmental sensing, Humidity, Simulation of CCA and DLA aggregates, Temperature metrology, Control systems, Transmitters, Actuators

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Proceedings Article | 22 July 2016 Paper

Paper

Results from bonding of the SALT primary mirror edge sensors

Ockert Strydom, Jonathan Love, Hitesh Gajjar

Proceedings Volume 9912, 991244 (2016) https://doi.org/10.1117/12.2233101

KEYWORDS: Sensors, Mirrors, Mirrors, Humidity, Connectors, Tolerancing, Adhesives, Telescopes, Image segmentation, Environmental sensing, Nanotechnology

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Proceedings Article | 22 July 2014 Paper

Paper

SALT segmented primary mirror: inductive edge sensors

Hitesh Gajjar, John Menzies, David Buckley, Christian Neel, Philippe Parbaud, Stéphane Royet

Proceedings Volume 9145, 91454X (2014) https://doi.org/10.1117/12.2056217

KEYWORDS: Sensors, Temperature metrology, Mirrors, Humidity, Environmental sensing, Actuators, Process control, Sensor performance, Telescopes, Sensing systems

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Proceedings Article | 20 July 2010 Paper

Paper

Cleaning the Southern African Large Telescope's M5 mirror

Lisa Crause, Hitesh Gajjar, Jonathan Love, Francois Strümpfer, James O'Connor, Darragh O'Donoghue, Ockert Strydom, David A. Buckley, Peter Gillingham

Proceedings Volume 7739, 77393Z (2010) https://doi.org/10.1117/12.856795

KEYWORDS: Mirrors, Laser sintering, Telescopes, Reflectivity, Sodium, Optical coatings, Monochromatic aberrations, Inspection, Polymer thin films, Polymers

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Proceedings Article | 19 July 2010 Paper

Paper

SALT segmented primary mirror: laboratory test results for FOGALE inductive edge sensors

John Menzies, Hitesh Gajjar, Sébastien Buous, David Buckley, Peter Gillingham

Proceedings Volume 7739, 77390X (2010) https://doi.org/10.1117/12.859130

KEYWORDS: Sensors, Mirrors, Environmental sensing, Space telescopes, Telescopes, Current controlled current source, Large telescopes, Nanotechnology, Sensor technology, Sensing systems

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Proceedings Article | 19 July 2010 Paper

Paper

A novel optical sensor for mirror edge sensing

D. A. Buckley, S. Buous, H. Gajjar, J. Menzies, F. Schindler, K. Sändig, S. Lévêque

Proceedings Volume 7739, 773912 (2010) https://doi.org/10.1117/12.858131

KEYWORDS: Sensors, Mirrors, Reticles, Telescopes, Humidity, Prototyping, Optical sensors, Environmental sensing, Climatology, Segmented mirrors

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Proceedings Article | 23 July 2008 Paper

Paper

The image quality of the Southern African Large Telescope (SALT)

Darragh O'Donoghue, Eli Atad-Ettedgui, Luis Balona, Bruce Bigelow, John Booth, Lucian Botha, Janus Brink, David Buckley, Phil Charles, Alrin Christians, J. Christopher Clemens, Lisa Crause, Steven Crawford, Geoffrey Evans, Hitesh Gajjar, Yas Hashimoto, Malcolm Hendricks, Alexei Kniazev, Anthony Koeslag, Willie Koorts, Herman Kriel, Nicola Loaring, Jonathan Love, Fred Marang, Douglas Metcalfe, Brennan Meyer, James O'Connor, Charl du Plessis, Lawrence Ramsey, Encarni Romero-Colmenero, Craig Sass, Johann Scholtz, Ramotholo Sefako, Sandisa Siyengo, Martin Still, Ockert Strydom, Arkadiusz Swat, Johann Du Toit, Petri Vaisanen, Martyn Wells, Hannah Worters

Proceedings Volume 7018, 701813 (2008) https://doi.org/10.1117/12.788841

KEYWORDS: Mirrors, Telescopes, Monochromatic aberrations, Image quality, Cameras, Simulation of CCA and DLA aggregates, Image segmentation, Wavefront sensors, Wavefronts, Interfaces

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Proceedings Article | 10 July 2008 Paper

Paper

SALT segmented primary mirror: commissioning capacitive edge sensing system and performance comparison with inductive sensor

Sebastien Buous, John Menzies, Hitesh Gajjar

Proceedings Volume 7012, 70123G (2008) https://doi.org/10.1117/12.788909

KEYWORDS: Sensors, Humidity, Mirrors, Temperature metrology, Sensing systems, Simulation of CCA and DLA aggregates, Telescopes, Calibration, Environmental sensing, Nanotechnology

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Proceedings Article | 10 July 2008 Paper

Paper

The use of primary mirrors as Hartmann masks for in situ alignment of segmented mirror telescopes

Steven Crawford, Martyn Wells, Hitesh Gajjar

Proceedings Volume 7012, 70123P (2008) https://doi.org/10.1117/12.788840

KEYWORDS: Image segmentation, Mirrors, Telescopes, Optical alignment, Monochromatic aberrations, Image quality, Large telescopes, Cameras, Imaging systems, Data modeling

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Proceedings Article | 23 June 2006 Paper

Paper

Results from the capacitive edge sensing system for the active alignment of the SALT primary mirror

Hitesh Gajjar, John Menzies, Jian Swiegers, Didier Rozière, Alain Courteville, Sebastien Buous, Bruno Luong

Proceedings Volume 6267, 626737 (2006) https://doi.org/10.1117/12.672103

KEYWORDS: Sensors, Mirrors, Sensing systems, Humidity, Temperature metrology, Control systems, Simulation of CCA and DLA aggregates, Actuators, Environmental sensing, Large telescopes

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Proceedings Article | 28 September 2004 Paper

Paper

Completion of the Southern African Large Telescope (SALT) primary mirror system

Jian Swiegers, Hitesh Gajjar

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.551410

KEYWORDS: Mirrors, Sensors, Telescopes, Image segmentation, Image quality, Actuators, Optical alignment, Optics manufacturing, Coating, Large telescopes

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Proceedings Article | 28 September 2004 Paper

Paper

Developing and testing an optical alignment system for SALT’s segmented primary mirror

Allan Wirth, Tom Gonsiorowski, Jennifer Roberts, Theresa Bruno, Jian Swiegers, Hitesh Gajjar, Arek Swat

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.551425

KEYWORDS: Sensors, Mirrors, Image segmentation, Error analysis, Simulation of CCA and DLA aggregates, Telescopes, Wavefronts, Beam splitters, Charge-coupled devices, Optical alignment

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Showing 5 of 19 publications

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