Mr. Janus D. Brink Profile

Janus D. Brink

Engineering Specialist at Southern African Large Telescope

SPIE Involvement:

Author

Publications (32)

Proceedings Article | 29 August 2022 Poster + Paper

Preparing the SALT for near-infrared observations

Janus Brink, Moses Mogotsi, Melanie Saayman, Nicolaas Van der Merwe, Jonathan Love, Alrin Christians

Proceedings Volume 12182, 121822E (2022) https://doi.org/10.1117/12.2627328

KEYWORDS: Near infrared, Telescopes, Calibration, Cameras, Stars, Spectrographs, Lamps, Interfaces, Mirrors, Light sources

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Proceedings Article | 13 December 2020 Poster + Presentation + Paper

A dual-beam spectrograph design for transient follow-up with SALT

Janus Brink, John Menzies, Ockert Strydom, Melanie Saayman

Proceedings Volume 11447, 1144768 (2020) https://doi.org/10.1117/12.2560996

KEYWORDS: Spectrographs, Received signal strength, Astronomy, Spectroscopy, Large Synoptic Survey Telescope, Optical instrument design, Large telescopes, Beam splitters, Spectral resolution, Cameras

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Proceedings Article | 10 July 2018 Presentation + Paper

Selecting a simple, natively implemented middleware solution for the SALT control system

Deneys Maartens, Janus Brink

Proceedings Volume 10707, 107070E (2018) https://doi.org/10.1117/12.2313106

KEYWORDS: LabVIEW, Control systems, Telecommunications, Observatories, Large telescopes, Telescopes, Logic, Switches, Receivers, Data transmission

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The Southern African Large Telescope (SALT) telescope control system is realised as a distributed control system, implemented predominantly in National Instruments’ LabVIEW. The telescope subsystems communicate using cyclic, state-based messages. Previously, we explored Data Distribution Service (DDS)—a data-centric publish-subscribe model for distributed application communication and integration, with the aim of using it as our primary communications middleware; however, obstacles uncovered during the implementation and roll-out of DDS prompted us to take a fresh look at the problem. We identified ZeroMQ (ZMQ) and NATS as possible alternative solutions. While ZMQ and NATS are both high-performance asynchronous messaging systems similar to DDS, the main difference between them is that ZMQ, in resemblance to DDS, is brokerless, whereas NATS is brokered. In a brokered system, the message broker mediates communication between a sender and a receiver, minimising the mutual awareness that applications need to have of each other in order to be able to exchange messages. Furthermore, less complexity is required in both the sender and the receiver of a message, when making use of a broker. A drawback of a broker, however, is that it may introduce a possible single point of failure. As a result of the simplicity of the client, coupled with the succinct NATS wire protocol, we were able to incorporate the NATS sender and receiver logic natively in our LabVIEW software. Taking advantage of a native solution removes the maintenance and deployment burden introduced by the use of an external C-language library, which is required for the use of both DDS and ZMQ. During our investigation of ZMQ we uncovered the same obstacles as we did with DDS, which involved the complexities of gracefully shutting down the communications logic when not using an object-oriented programming methodology. Due to legacy software, we have to maintain backward compatibility with a version of LabVIEW which predates the availability of built-in object-orientation in the language. This, coupled with the advantages of a native solution, led to the adoption of NATS as our messaging system. In this paper, we explore ZMQ and NATS as alternatives to DDS, accompanied with results of a performance evaluation of DDS, ZMQ and NATS against our home-grown legacy HTTP-based messaging implementation. We conclude with a summary and describe future work.

Proceedings Article | 10 July 2018 Paper

Preparing SALT's software for the future

Christian Hettlage, Encarnacion Romero Colmenero, Steven Crawford, Nhlavutelo Macebele, Anelisiwe Mayekiso, Rosalind Skelton, Rudolf Kuhn, Petri Väisänen, Janus Brink, Anthony Koeslag, Stephen Hulme

Proceedings Volume 10704, 107042D (2018) https://doi.org/10.1117/12.2313834

KEYWORDS: Databases, Telescopes, Software development, Astronomy, Observatories

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Proceedings Article | 10 July 2018 Paper

A high-efficiency low-resolution spectrograph design for SALT

Janus Brink, Ockert Strydom, Magaretha Pretorius, Petri S. Vaisanen

Proceedings Volume 10706, 107066H (2018) https://doi.org/10.1117/12.2313130

KEYWORDS: Sensors, Telescopes, Spectrographs, Spherical lenses, Mirrors, Spectroscopy, Astronomy, Observatories, Optical design, Large telescopes

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Proceedings Article | 10 July 2018 Paper

Performance of the updated Southern African Large Telescope prime-focus guidance system

Janus Brink, Ockert Strydom, Stephen Hulme, Anthony Koeslag, Deneys Maartens, Keith R. Browne, Eben Wiid

Proceedings Volume 10706, 1070668 (2018) https://doi.org/10.1117/12.2313120

KEYWORDS: Telescopes, Sensors, Imaging systems, Control systems, Stars, Received signal strength, Prisms, Beam splitters, Motion controllers

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Proceedings Article | 6 July 2018 Paper

Development of a centralised change logging system for the Southern African Large Telescope

Stephen Hulme, Deneys Maartens, Janus Brink, Anthony Koeslag

Proceedings Volume 10707, 107072N (2018) https://doi.org/10.1117/12.2313215

KEYWORDS: Databases, Telescopes, Prototyping, Large telescopes, Observatories, Astronomical telescopes, Software development

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Proceedings Article | 6 July 2018 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

Image processing for a pyramid wavefront sensor equipped guide probe on SALT

Anthony Koeslag, Janus Brink, Stephen Hulme, Ockert Strydom, Deneys Maartens

Proceedings Volume 10707, 107072M (2018) https://doi.org/10.1117/12.2313142

KEYWORDS: Stars, Image processing, Telescopes, Received signal strength, Cameras, Wavefront sensors, Prisms, Mirrors, Observatories, Waveguides

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A new guide probe, using a Pyramid WaveFront Sensor (PWFS), has been built for the guider port of the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT). The PWFS splits the light from a guide star into a double image of the star at the guider image plane. These two images move with respect to each other with changes in focus. Analysis of the movements in such two-star images allows for simultaneous tracking and focus adjustments while guiding. This paper describes the image processing software developed for the new guidance system. The PWFS is a custom made prism with a 9 degree prism apex angle. Incident light is split as it passes through the prism resulting in two images identical in shape, size and orientation resolving at the guider image plane. A point source, like a star, thus appears as a double image of the star at the image plane. These two images are affected identically with seeing fluctuations allowing one or both images to be used to calculate guidance offsets independently of the focus measurement. The separation of the two images correlates to the focus divergence from the ideal which is used to correct the telescope focus. The prism can be moved off to one side, such that the incident light is not split. In this configuration the guide probe provides guidance offsets without the focus adjustments for maximum sensitivity with dim guide. The software was developed using existing guider images to ensure that the algorithm could handle the image artefacts that are commonly encountered. To reduce processing time and the effects of anomalies the surrounding image is masked out leaving only the star. A centroiding algorithm is then applied to the star to estimate its location in the image. For PWFS double-star images, Zemax was used to model the effect of shifting focus on the light passing through the prism. From this a simulated data set was produced and the software expanded to detect the two stars and measure the separation. The software is capable of measuring star translational movements and double star separation reliability and accurately.

Proceedings Article | 18 August 2016 Paper

SALT tracker upgrade utilizing aerospace processes and procedures

Raoul van den Berg, Chris Coetzee, Ockert Strydom, Janus Brink, Keith Browne, Eben Wiid, Wouter Lochner, Grant Nelson, Paul Rabe, Martin Wilkinson, Vic Moore, Adelaide Malan, Jonathan Love, Anthony Koeslag

Proceedings Volume 9911, 99111J (2016) https://doi.org/10.1117/12.2231559

KEYWORDS: Aerospace engineering, Telescopes, Safety, Mechanical engineering, Manufacturing, Computer aided design, Design for manufacturability, Inspection, Actuators, Finite element methods

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Proceedings Article | 9 August 2016 Paper

Commissioning the polarimetric modes of the Robert Stobie spectrograph on the Southern African Large Telescope

S. Potter, Ken Nordsieck, Encarni Romero-Colmenero, Steve Crawford, Petri Vaisanen, Éric Depagne, David Buckley, Anthony Koeslag, Janus Brink, Christian Hetlage, Keith Browne, Lisa Crause, Alan Schier, James Allington

Proceedings Volume 9908, 99082K (2016) https://doi.org/10.1117/12.2232391

KEYWORDS: Polarimetry, Beam splitters, Calcite, Spectrographs, Large telescopes, Received signal strength, Imaging spectroscopy, Polarimetry, Spectrographs, Polarization, Prisms, Stars

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Proceedings Article | 27 July 2016 Paper

Glycol leak detection system

Paul Rabe, Keith Browne, Janus Brink, Christiaan Coetzee

Proceedings Volume 9906, 99065H (2016) https://doi.org/10.1117/12.2231396

KEYWORDS: Sensors, Electronics, Large telescopes, Telescopes, Transmitters, Surface plasmons, Resistance, Liquids, Seaborgium, Control systems

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Proceedings Article | 26 July 2016 Paper

DDS as middleware of the Southern African Large Telescope control system

Deneys Maartens, Janus Brink

Proceedings Volume 9913, 99130O (2016) https://doi.org/10.1117/12.2231638

KEYWORDS: Control systems, LabVIEW, Large telescopes, Telescopes, Telecommunications, Data modeling, Systems modeling, Data communications, Observatories, Switches

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The Southern African Large Telescope (SALT) software control system1 is realised as a distributed control system, implemented predominantly in National Instruments' LabVIEW. The telescope control subsystems communicate using cyclic, state-based messages. Currently, transmitting a message is accomplished by performing an HTTP PUT request to a WebDAV directory on a centralised Apache web server, while receiving is based on polling the web server for new messages. While the method works, it presents a number of drawbacks; a scalable distributed communication solution with minimal overhead is a better fit for control systems. This paper describes our exploration of the Data Distribution Service (DDS). DDS is a formal standard specification, defined by the Object Management Group (OMG), that presents a data-centric publish-subscribe model for distributed application communication and integration. It provides an infrastructure for platform- independent many-to-many communication. A number of vendors provide implementations of the DDS standard; RTI, in particular, provides a DDS toolkit for LabVIEW. This toolkit has been evaluated against the needs of SALT, and a few deficiencies have been identified. We have developed our own implementation that interfaces LabVIEW to DDS in order to address our specific needs. Our LabVIEW DDS interface implementation is built against the RTI DDS Core component, provided by RTI under their Open Community Source licence. Our needs dictate that the interface implementation be platform independent. Since we have access to the RTI DDS Core source code, we are able to build the RTI DDS libraries for any of the platforms on which we require support. The communications functionality is based on UDP multicasting. Multicasting is an efficient communications mechanism with low overheads which avoids duplicated point-to-point transmission of data on a network where there are multiple recipients of the data. In the paper we present a performance evaluation of DDS against the current HTTP-based implementation as well as the historical DataSocket implementation. We conclude with a summary and describe future work.

Proceedings Article | 22 July 2016 Paper

A new modular guidance system for the Southern African Large Telescope

Janus Brink, Ockert Strydom, Stephen Hulme, Anthony Koeslag, Deneys Maartens, Martin Wilkinson, Wouter Lochner, Keith Browne, Eben Wiid, Raoul van den Berg

Proceedings Volume 9912, 99125F (2016) https://doi.org/10.1117/12.2231407

KEYWORDS: Optical design, Control systems, Optical design, Control systems design, Received signal strength, Telescopes, Computer programming, Sensors, Prisms, Imaging systems, Cameras

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Proceedings Article | 22 July 2016 Paper

Transmission and opto-mechanical performance of the liquid lens coupling in the Robert Stobie Spectrograph on SALT

Ockert Strydom, Éric Depagne, Darragh O'Donoghue, Martin Wilkinson, Wouter Lochner, Jonathan Love, Lisa Crause, Janus Brink, Kenneth Nordsieck, J. Alan Schier

Proceedings Volume 9912, 99123D (2016) https://doi.org/10.1117/12.2232243

KEYWORDS: Liquid lenses, Absorption, Liquids, Spectrographs, Received signal strength, Collimators, Reflectivity, Ultraviolet radiation, Ocean optics, Optical testing

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Proceedings Article | 15 July 2016 Paper

Worth its SALT: four years of full science operations with the Southern African Large Telescope

Petri Väisänen, Chris Coetzee, Anja Schroeder, Steve Crawford, David Buckley, Janus Brink, Éric Depagne, Alexei Kniazev, Thea Koen, Paul Kotze, Fred Marang, Brent Miszalski, Encarni Romero Colmenero, Ockert Strydom, Veronica Van Wyk, Theodore Williams

Proceedings Volume 9910, 99100T (2016) https://doi.org/10.1117/12.2232873

KEYWORDS: Observatories, Large telescopes, Telescopes, Gemini Observatory, Mirrors, Coating, Adaptive optics, Gemini Planet Imager, Turbulence, Structural engineering

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Proceedings Article | 11 July 2016 Paper

Monitoring the performance of the Southern African Large Telescope

Christian Hettlage, Chris Coetzee, Petri Väisänen, Encarni Romero Colmenero, Steven Crawford, Paul Kotze, Paul Rabe, Stephen Hulme, Janus Brink, Deneys Maartens, Keith Browne, Ockert Strydom, David De Bruyn

Proceedings Volume 9910, 99102M (2016) https://doi.org/10.1117/12.2230484

KEYWORDS: Telescopes, Large telescopes, Astronomical telescopes, Efficient operations, Automatic tracking

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Proceedings Article | 7 August 2014 Paper

Commissioning the SALT fiber instrument feed

Janus Brink, Ockert Strydom, Darragh O'Donoghue, Eben Wiid

Proceedings Volume 9151, 915121 (2014) https://doi.org/10.1117/12.2055943

KEYWORDS: Computer programming, Telescopes, Cameras, Stars, Human-machine interfaces, Target acquisition, Motion models, Imaging systems, Motion controllers, Control systems

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Proceedings Article | 24 July 2014 Paper

Performance of the Southern African Large Telescope (SALT) High Resolution Spectrograph (HRS)

Lisa Crause, Ray Sharples, David Bramall, Jürgen Schmoll, Paul Clark, Eddy Younger, Luke Tyas, Sean Ryan, Janus Brink, Ockert Strydom, David Buckley, Martin Wilkinson, Steven Crawford, Éric Depagne

Proceedings Volume 9147, 91476T (2014) https://doi.org/10.1117/12.2055635

KEYWORDS: Spectrographs, Stars, Spectral resolution, Mirrors, Calibration, Telescopes, Iodine cells, Large telescopes, Lawrencium, Cameras

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SPIE Journal Paper | 11 February 2013

Resolving the Southern African Large Telescope’s image quality problems

Darragh O'Donoghue, Lisa Crause, James O'Connor, Francois Strumpfer, Ockert Strydom, Craig Sass, Janus Brink, Charl du Plessis, Eben Wiid, Jonathan Love

OE, Vol. 52, Issue 08, 081604, (February 2013) https://doi.org/10.1117/12.10.1117/1.OE.52.8.081604

KEYWORDS: Mirrors, Telescopes, Monochromatic aberrations, Computer generated holography, Interfaces, Large telescopes, Image quality, Stars, Cameras, Optical testing

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Proceedings Article | 24 September 2012 Paper

The SALT HRS spectrograph: instrument integration and laboratory test results

D. Bramall, J. Schmoll, L. M. Tyas, P. Clark, E. Younger, R. Sharples, N. Dipper, S. Ryan, D. Buckley, J. Brink

Proceedings Volume 8446, 84460A (2012) https://doi.org/10.1117/12.925935

KEYWORDS: Spectrographs, Mirrors, Cameras, Charge-coupled devices, Sensors, Lawrencium, Optics manufacturing, Telescopes, Coating, Optical alignment

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Proceedings Article | 17 September 2012 Paper

A happy conclusion to the SALT image quality saga

Lisa Crause, Darragh O'Donoghue, James O'Connor, Francois Strumpfer, Ockert Strydom, Craig Sass, Charl du Plessis, Eben Wiid, Jonathan Love, Janus Brink, Martin Wilkinson, Chris Coetzee

Proceedings Volume 8444, 84444I (2012) https://doi.org/10.1117/12.924997

KEYWORDS: Mirrors, Telescopes, Stars, Computer generated holography, Image quality, Interfaces, Optical testing, Autocollimators, Aluminum, Monochromatic aberrations

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Proceedings Article | 20 July 2010 Paper

The SALT HRS spectrograph: final design, instrument capabilities, and operational modes

D. Bramall, R. Sharples, L. Tyas, J. Schmoll, P. Clark, P. Luke, N. Looker, N. Dipper, S. Ryan, D. A. Buckley, J. Brink, S. Barnes

Proceedings Volume 7735, 77354F (2010) https://doi.org/10.1117/12.856382

KEYWORDS: Spectrographs, Charge-coupled devices, Stars, Spectral resolution, Telescopes, Astronomy, Optical design, Sensors, Optics manufacturing, Cameras

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Proceedings Article | 19 July 2010 Paper

Control software architecture for the SALT Robert Stobie Spectrograph

Anthony Koeslag, Janus Brink, Peter Menzies, Kenneth Nordsieck, Jeffr Percival, Theodore Williams

Proceedings Volume 7740, 774006 (2010) https://doi.org/10.1117/12.856895

KEYWORDS: Received signal strength, Fabry–Perot interferometers, Cameras, LabVIEW, Spectrographs, Optical filters, Computer architecture, Astronomy, Software development, Telescopes

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Proceedings Article | 19 July 2010 Paper

Saving SALT: repairs to the spherical aberration corrector of the Southern African Large Telescope (SALT)

Darragh O'Donoghue, James O'Connor, Lisa Crause, Francois Strumpfer, Ockert Strydom, Janus Brink, Craig Sass, Eben Wiid, Eli Atad-Ettedgui

Proceedings Volume 7739, 77390Q (2010) https://doi.org/10.1117/12.856239

KEYWORDS: Telescopes, Mirrors, Computer generated holography, Monochromatic aberrations, Interfaces, Image quality, Optical alignment, Optical testing, Large telescopes, Cameras

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Proceedings Article | 15 July 2010 Paper

Spectropolarimetry with the SALT RSS

Janus Brink, David A. Buckley, Kenneth Nordsieck, Stephen Potter

Proceedings Volume 7735, 773517 (2010) https://doi.org/10.1117/12.856932

KEYWORDS: Polarization, Polarimetry, Received signal strength, Telescopes, Wave plates, Error analysis, Astronomy, Stars, Polarizers, Sensors

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Proceedings Article | 25 July 2008 Paper

The optical design of the Southern African Large Telescope high resolution spectrograph: SALT HRS

S. Barnes, P. Cottrell, M. Albrow, N. Frost, G. Graham, G. Kershaw, R. Ritchie, D. Jones, R. Sharples, D. Bramall, J. Schmoll, P. Luke, P. Clark, L. Tyas, D. A. Buckley, J. Brink

Proceedings Volume 7014, 70140K (2008) https://doi.org/10.1117/12.788219

KEYWORDS: Cameras, Mirrors, Spectrographs, Spectral resolution, Charge-coupled devices, Optical design, Image quality, Large telescopes, Sensors, Lenses

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Proceedings Article | 23 July 2008 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 | 14 July 2008 Paper

The SALT observation control system

Janus Brink, Anne Charles, Christian Hettlage, Tim-Oliver Husser, Anthony Koeslag, Encarni Romero-Colmenero

Proceedings Volume 7019, 70190N (2008) https://doi.org/10.1117/12.787632

KEYWORDS: Telescopes, Control systems, Calibration, Human-machine interfaces, Databases, Mirrors, Interfaces, Control systems design, Electroluminescence, Received signal strength

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Proceedings Article | 9 July 2008 Paper

The Southern African Large Telescope (SALT) calibration system

D. A. Buckley, J. Brink, N. Loaring, A. Swat, H. Worters

Proceedings Volume 7014, 70146H (2008) https://doi.org/10.1117/12.790385

KEYWORDS: Calibration, Lamps, Mirrors, Waveguides, Diffusers, Telescopes, Vignetting, Fresnel lenses, Liquids, Astronomy

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Proceedings Article | 28 September 2004 Paper

SALT prime focus payload development

Schalk Esterhuyse, Janus Brink, Cornelius Nel, Arek Swat

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.551358

KEYWORDS: Mirrors, Telescopes, Space telescopes, Calibration, Prisms, Sensors, Monochromatic aberrations, Manufacturing, Cameras, Optical instrument design

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Proceedings Article | 15 September 2004 Paper

Facing software complexity on large telescopes

Gerhard Swart, Deon Bester, Janus Brink, Clifford Gumede, Hendrik Schalekamp

Proceedings Volume 5496, (2004) https://doi.org/10.1117/12.551455

KEYWORDS: Telescopes, Software development, Human-machine interfaces, LabVIEW, Standards development, Computer architecture, Control systems, Optical instrument design, Mirrors, Large telescopes

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Showing 5 of 32 publications

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