Dr. Gert Raskin Profile

Dr. Gert Raskin

Instrumentation Specialist at KU Leuven

SPIE Involvement:

Author

Area of Expertise:

Astronomical instrumentation , Spectroscopy , Telescopes , Optical design

Publications (30)

Proceedings Article | 3 January 2020 Paper

Fiber modal noise mitigation by a rotating double scrambler

G. Raskin, D. Rogozin, T. Mladenov, C. Schwab, D. Coutts

Proc. SPIE. 11203, Advances in Optical Astronomical Instrumentation 2019

KEYWORDS: Signal to noise ratio, Multimode fibers, Optical fibers, Spectrographs, Astronomy, Lenses, Speckle pattern, Velocity measurements

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Proceedings Article | 3 January 2020 Paper

Rubidium transitions as wavelength reference for astronomical Doppler spectrographs

D. Rogozin, T. Feger, C. Schwab, Y. Gurevich, G. Raskin, D. Coutts, J. Stuermer, A. Seifahrt, T. Fuehrer, T. Legero, H. Van Winckel, S. Halverson, A. Quirrenbach

Proc. SPIE. 11203, Advances in Optical Astronomical Instrumentation 2019

KEYWORDS: Spectrographs, Astronomy, Fabry–Perot interferometers, Doppler effect, Calibration, Spectroscopy, Spectral calibration, Absorption spectroscopy, Rubidium, Absorption

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Proceedings Article | 24 July 2018 Paper

CUBESPEC: low-cost space-based astronomical spectroscopy

Gert Raskin, Tjorven Delabie, Wim De Munter, Hugues Sana, Bart Vandenbussche, Bram Vandoren, Victoria Antoci, Hans Kjeldsen, Christoffer Karoff, Alex de Koter, Jean-Michel Désert, Tom Mladenov, Dirk Vandepitte

Proc. SPIE. 10698, Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave

KEYWORDS: Telescopes, Mirrors, Spectrographs, Stars, Sensors, Spectroscopy, Exoplanets, Space telescopes, Spectral resolution, Space operations

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Proceedings Article | 18 July 2018 Presentation

The BlackGEM array (Conference Presentation)

Paul Groot, Steven Bloemen, Peter Jonker, Paul Vreeswijk, Kerry Paterson, Rik ter Horst, Ramon Navarro, Dirk Lesman, Arno Engels, Roy Bakker, Harrie Rutten, Gert Raskin, Conny Aerts, Gijs Nelemans

Proc. SPIE. 10700, Ground-based and Airborne Telescopes VII

KEYWORDS: Observatories, Telescopes, Mirrors, Databases, Image processing, Photometry, Lanthanum, Spherical lenses, Optical arrays, Mirror stabilization

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The BlackGEM Phase 1 array for optical synoptic surveys consists of three wide-field telescopes providing an 8.1 square degrees field-of-view sampled at 0.56". It will be installed at the ESO La Silla Observatory. Each unit telescope consists of a modified Dall-Kirkham (Wynne-Harmer) configuration with a 65cm parabolic primary mirror, a 23cm spherical secondary and a triplet corrector lens. The third lens in the triplet is motorized to double as an Atmospheric Dispersion Corrector. The 10cm x 10cm flat, achromatic focal plane contains a single STA1600 10.5k x 10.5k chip with 9 micron pixels, providing a 2.7 square degree field-of-view sampled at 0.56"/pix. The telescope is equipped with a 6 slot (u,g,q,r,i,z) filter wheel. Limiting magnitude (5 sigma) in dark conditions is q=23 in 300s integration in 1" seeing. The telescope structure is made from carbon-fibre for maximum stability. The secondary mirror is mounted on a piezo-stage for active control. Each telescope is mounted on the Fornax 200 mount. On La Silla each telescope will be housed in a clamshell dome, and be located on a 7m high double-walled cylinder to lift it above the ground-layer seeing. The outer cylinder will carry the dome and the inner cylinder the telescope. The scientific program of BlackGEM is centered on optical afterglows of gravitational wave mergers, reacting to Advanced LIGO/Virgo triggers. The array will also perform a full southern sky survey (BG-SASS), covering 30000 square degrees (Dec < +30d) down to 22nd magnitude in all six filters at 1" resolution; a fast synoptic survey at 1 minute cadence for characterization of fast transients; bi-weekly all-sky q-band scan; and a twilight survey of the local universe. The BlackGEM consortium consists of the Netherlands Research School for Astronomy (NOVA), Radboud University and KU Leuven as founding members and the University of Manchester, UC Davis, Tel Aviv University, the Weizmann Institute, the University of Canterbury and the Hebrew University Jerusalem as partners. BlackGEM data will be processed on-line for transients and a full-source database using optimal photometry and the ZOGY image subtraction techniques. BlackGEM transients will be announced publically upon detection. All BlackGEM data will be cloud-based, including the 150Tb live database of the full source photometry. BlackGEM Phase 1 is scheduled for installation on La Silla in Q2-Q3 2018 and start of operations of in Q4 2018. In Phase 2 (2019-2022) the array is to be expanded to 15 unit telescopes, providing a 40.5 square degree instantaneous field-of-view. An overview of the array, first results of the prototype and an update of the installation will be given. www.blackgem.org

Proceedings Article | 16 July 2018 Paper

Characterization of the per-pixel dark current and activation energy of a large format CMOS image sensor

Swaraj Bandhu Mahato, Gert Raskin, Guy Meynants, Joris De Ridder, Hans Van Winckel

Proc. SPIE. 10709, High Energy, Optical, and Infrared Detectors for Astronomy VIII

KEYWORDS: CMOS sensors, Astronomy, Imaging systems, Sensors, Photodiodes, Image sensors, Temperature sensors

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Proceedings Article | 16 July 2018 Paper

Two-dimensional MTF characterization of a large format CMOS detector

Swaraj Bandhu Mahato, Joris De Ridder, Guy Meynants, Gert Raskin, Hans Van Winckel

Proc. SPIE. 10709, High Energy, Optical, and Infrared Detectors for Astronomy VIII

KEYWORDS: Point spread functions, CMOS sensors, Imaging systems, Sensors, Image sensors, Modulation transfer functions

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Proceedings Article | 9 July 2018 Paper

Rubidium traced etalon wavelength calibrators: towards deployment at observatories

Christian Schwab, Tobias Feger, Julian Stürmer, Andreas Seifahrt, Yulia Gurevich, Dmytro Rogozin, Thorsten Führer, Samuel Halverson, Ryan Terrien, Thomas Legero, David Coutts, Gert Raskin, Thomas Walther, Jacob Bean, Andreas Quirrenbach

Proc. SPIE. 10702, Ground-based and Airborne Instrumentation for Astronomy VII

KEYWORDS: Observatories, Spectrographs, Fabry–Perot interferometers, Calibration, Spectroscopy, Optical coatings, Spectral calibration, Rubidium

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Proceedings Article | 6 July 2018 Paper

Testing and calibrating an advanced cubesat attitude determination and control system

Tjorven Delabie, Bram Vandoren, Wim De Munter, Gert Raskin, Bart Vandenbussche, Dirk Vandepitte

Proc. SPIE. 10698, Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave

KEYWORDS: Stars, Cameras, Calibration, Error analysis, Control systems, Optical tracking, Space operations, Optical calibration

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Proceedings Article | 6 July 2018 Paper

Development of an alignment platform for ESO's mid-infrared E-ELT imager and spectrograph (METIS)

André Boné, António Amorim, Paulo Gordo, Izabella Hemprich, Gabby Kroes, Adrian Glauser, Stephen March, Gert Raskin, Paulo Garcia

Proc. SPIE. 10698, Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave

KEYWORDS: Actuators, Mid-IR, Telescopes, Spectrographs, Imaging systems, Kinematics, 3D modeling, Earthquakes

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Proceedings Article | 9 May 2018 Paper

Kernel-based crosstalk quantification and analysis of a CMOS image sensor

Swaraj Bandhu Mahato, Joris De Ridder, Guy Meynants, Gert Raskin, Hans Van Winckel

Proc. SPIE. 10680, Optical Sensing and Detection V

KEYWORDS: Microscopes, Point spread functions, Optical filters, CMOS sensors, Imaging systems, Sensors, Image sensors, Charge-coupled devices, Raster graphics, Motion controllers

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Proceedings Article | 9 August 2016 Paper

PLC-controlled cryostats for the BlackGEM and MeerLICHT detectors

Gert Raskin, Johan Morren, Wim Pessemier, Steven Bloemen, Marc Klein-Wolt, Ronald Roelfsema, Paul Groot, Conny Aerts

Proc. SPIE. 9908, Ground-based and Airborne Instrumentation for Astronomy VI

KEYWORDS: Telescopes, Electronics, Fluctuations and noise, Sensors, Robotics, Control systems, Charge-coupled devices, Photonic integrated circuits, CCD image sensors, Control systems design

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BlackGEM is an array of telescopes, currently under development at the Radboud University Nijmegen and at NOVA (Netherlands Research School for Astronomy). It targets the detection of the optical counterparts of gravitational waves. The first three BlackGEM telescopes are planned to be installed in 2018 at the La Silla observatory (Chile). A single prototype telescope, named MeerLICHT, will already be commissioned early 2017 in Sutherland (South Africa) to provide an optical complement for the MeerKAT radio array. The BlackGEM array consists of, initially, a set of three robotic 65-cm wide-field telescopes. Each telescope is equipped with a single STA1600 CCD detector with 10.5k x 10.5k 9-micron pixels that covers a 2.7 square degrees field of view. The cryostats for housing these detectors are developed and built at the KU Leuven University (Belgium). The operational model of BlackGEM requires long periods of reliable hands-off operation. Therefore, we designed the cryostats for long vacuum hold time and we make use of a closed-cycle cooling system, based on Polycold PCC Joule-Thomson coolers. A single programmable logic controller (PLC) controls the cryogenic systems of several BlackGEM telescopes simultaneously, resulting in a highly reliable, cost-efficient and maintenance-friendly system. PLC-based cryostat control offers some distinct advantages, especially for a robotic facility. Apart of temperature monitoring and control, the PLC also monitors the vacuum quality, the power supply and the status of the PCC coolers (compressor power consumption and temperature, pressure in the gas lines, etc.). Furthermore, it provides an alarming system and safe and reproducible procedures for automatic cool down and warm up. The communication between PLC and higher-level software takes place via the OPC-UA protocol, offering a simple to implement, yet very powerful interface. Finally, a touch-panel display on the PLC provides the operator with a user-friendly and robust technical interface. In this contribution, we present the design of the BlackGEM cryostats and of the PLC-based control system.

Proceedings Article | 8 August 2016 Paper

Knowledge-based engineering of a PLC controlled telescope

Wim Pessemier, Gert Raskin, Philippe Saey, Hans Van Winckel, Geert Deconinck

Proc. SPIE. 9913, Software and Cyberinfrastructure for Astronomy IV

KEYWORDS: Human-machine interfaces, Telescopes, Electronics, Logic, Safety, Control systems, Control systems, Computer programming, Photonic integrated circuits, Photonic integrated circuits, Optical proximity correction, Systems modeling, Systems modeling

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As the new control system of the Mercator Telescope is being finalized, we can review some technologies and design methodologies that are advantageous, despite their relative uncommonness in astronomical instrumentation. Particular for the Mercator Telescope is that it is controlled by a single high-end soft-PLC (Programmable Logic Controller). Using off-the-shelf components only, our distributed embedded system controls all subsystems of the telescope such as the pneumatic primary mirror support, the hydrostatic bearing, the telescope axes, the dome, the safety system, and so on. We show how real-time application logic can be written conveniently in typical PLC languages (IEC 61131-3) and in C++ (to implement the pointing kernel) using the commercial TwinCAT 3 programming environment. This software processes the inputs and outputs of the distributed system in real-time via an observatory-wide EtherCAT network, which is synchronized with high precision to an IEEE 1588 (PTP, Precision Time Protocol) time reference clock. Taking full advantage of the ability of soft-PLCs to run both real-time and non real-time software, the same device also hosts the most important user interfaces (HMIs or Human Machine Interfaces) and communication servers (OPC UA for process data, FTP for XML configuration data, and VNC for remote control). To manage the complexity of the system and to streamline the development process, we show how most of the software, electronics and systems engineering aspects of the control system have been modeled as a set of scripts written in a Domain Specific Language (DSL). When executed, these scripts populate a Knowledge Base (KB) which can be queried to retrieve specific information. By feeding the results of those queries to a template system, we were able to generate very detailed “browsable” web-based documentation about the system, but also PLC software code, Python client code, model verification reports, etc. The aim of this paper is to demonstrate the added value that technologies such as soft-PLCs and DSL-scripts and design methodologies such as knowledge-based engineering can bring to astronomical instrumentation.

Proceedings Article | 27 July 2016 Paper

Noise optimization of the source follower of a CMOS pixel using BSIM3 noise model

Swaraj Mahato, Guy Meynants, Gert Raskin, J. De Ridder, H. Van Winckel

Proc. SPIE. 9915, High Energy, Optical, and Infrared Detectors for Astronomy VII

KEYWORDS: CMOS sensors, Capacitors, Capacitance, Transistors, Cadmium sulfide, Field effect transistors, CMOS technology, Optimization (mathematics), Optimization (mathematics), Thermal modeling, Device simulation

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Proceedings Article | 27 July 2016 Paper

MeerLICHT and BlackGEM: custom-built telescopes to detect faint optical transients

Steven Bloemen, Paul Groot, Patrick Woudt, Marc Klein Wolt, Vanessa McBride, Gijs Nelemans, Elmar Körding, Margaretha Pretorius, Ronald Roelfsema, Felix Bettonvil, Harry Balster, Roy Bakker, Peter Dolron, Arjen van Elteren, Eddy Elswijk, Arno Engels, Rob Fender, Marc Fokker, Menno de Haan, Klaas Hagoort, Jasper de Hoog, Rik ter Horst, Giel van der Kevie, Stanisław Kozłowski, Jan Kragt, Grzegorz Lech, Rudolf Le Poole, Dirk Lesman, Johan Morren, Ramon Navarro, Willem-Jelle Paalberends, Kerry Paterson, Rafal Pawłaszek, Wim Pessemier, Gert Raskin, Harrie Rutten, Bart Scheers, Menno Schuil, Piotr Sybilski

Proc. SPIE. 9906, Ground-based and Airborne Telescopes VI

KEYWORDS: Observatories, Telescopes, Telescopes, Mirrors, Electronics, Stars, Stars, Radio optics, Charge-coupled devices, Lanthanum, Optical instrument design, Electroluminescent displays

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Proceedings Article | 5 July 2016 Paper

The BlackGEM array in search of black hole mergers: integrated performance modelling

Ronald Roelfsema, Marc Klein Wolt, Steven Bloemen, Paul Groot, Felix Bettonvil, Harry Balster, Peter Dolron, Arjen van Elteren, Arno Engels, Menno de Haan, Rik ter Horst, Jan Kragt, Ramon Navarro, Gijs Nelemans, Willem Jelle Paalberends, Sari Pal, Gert Raskin, Harrie Rutten, Bart Scheers, Menno Schuil, Piotr Sybilski

Proc. SPIE. 10012, Integrated Modeling of Complex Optomechanical Systems II

KEYWORDS: Signal to noise ratio, Point spread functions, Telescopes, Mirrors, MATLAB, Sensors, Control systems, Integrated modeling, Simulink, Performance modeling, Excel, Thermal modeling, Instrument modeling

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The Radboud University Nijmegen in collaboration with the NOVA Optical Infrared Instrumentation group at ASTRON is currently leading the development and realization of the BlackGEM observing facility. The BlackGEM science team aims to be the first to catch the optical counterpart of a gravitational wave event. The BlackGEM project will put an array of three medium-sized optical telescopes at the La Silla site of the European Southern Observatory in Chile. It is uniquely equipped to achieve a combination of wide-field and high sensitivity through its array-like approach. Each BlackGEM unit telescope is a modified Dall-Kirkham-type telescope consisting of a 65cm primary mirror, a 21cm spherical secondary mirror and a triplet corrector lens. The spatial resolution on the sky will be 0.56 asec/pixel and the total field-of-view per telescope is 2.7 square degrees. The main requirement is to achieve a 5-sigma sensitivity of 23rd magnitude within a 5-minute exposure under 15 m/s wind gust conditions. This demands a very stable optical system with tight control of all the error contributions. This has been realized with a spreadsheet based integrated instrument model. The model contains all relevant telescope instrument parameters and environmental conditions. The spreadsheet is partly used for performance calculations and partly used to combine and integrate the output from several other sources. The spreadsheet model calculates the overall performance based on an Exposure Time Calculator using the Noise Equivalent Area metric (NEA). The NEA is further budgeted over 7 main High Level Requirements. The spreadsheet model is coupled to 1) a ZEMAX telescope optical model 2) a telescope FEM analysis to predict the optomechanical response under various gravity, temperature and wind load conditions, 3) a Matlab Simulink thermal model to predict the transient temperature behaviour of the most important telescope elements and 4) a Matlab Simulink control model to predict the performance of the active M2 mirror. All outputs are collected in a system performance budget that readily shows the compliance with the main High Level Requirements.

Proceedings Article | 22 July 2014 Paper

The Mercator telescope: relevance, status, and future

Gert Raskin, Wim Pessemier, Florian Merges, Jesus Pérez Padilla, Saskia Prins, Hans Van Winckel

Proc. SPIE. 9145, Ground-based and Airborne Telescopes V

KEYWORDS: Telescopes, Mirrors, Spectrographs, Stars, Imaging systems, Control systems, Space telescopes, Astronomical telescopes, Photonic integrated circuits, Optical proximity correction

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In todays era of ever growing telescope apertures, there remains a specific niche for meter-class telescopes, provided they are equipped with efficient and dedicated instruments. In case these telescopes have permanent and long-term availability, they turn out very useful for intensive monitoring campaigns over a large range of time-scales. Flexible scheduling and time allocation allow small telescopes to rapidly seize new opportunities or provide immediate follow-up observations to complement data from large ground-based or space-borne facilities. The Mercator telescope, a 1.2-m telescope, installed at the Roque de Los Muchachos Observatory on La Palma (Canary Islands, Spain), successfully targets this niche of intensive monitoring and flexible scheduling. Mercator is already in operation since 2001 and has seen several upgrades in the mean time. In this contribution we give an update about the actual telescope status and its performance. We also present the Mercator instrument suite that currently consists of two instruments. The workhorse instrument is HERMES, a very efficient and stable fibre-fed high-resolution spectrograph. Recently, the MAIA imager was commissioned. This is a three- channel photometric instrument that observes a large field simultaneously in the different color bands. The MAIA detectors are unique 6k x 2k frame transfer devices which also allow for fast and continuous monitoring of variable phenomena.We discuss two important upcoming upgrades: a long-awaited automatic mirror cover and, more importantly, an entirely new telescope control system (TCS). This TCS is based on modern PLC technology, and relies on OPC UA and EtherCAT communication. Only commercially off-the-shelve hardware will be used for controlling the telescope. As a test case and as a precursor of the full TCS, such PLC systems are already deployed at Mercator to steer the Nasmyth mirror mechanism and to control the MAIA instrument. Finally, we also give an overview of the exploitation scheme of the telescope, the scheduling software that we developed to guarantee that time series or time-critical observations can be acquired in an efficient way, and how this all serves the most important research themes for Mercator, mainly in the domain of stellar astrophysics.

Proceedings Article | 18 July 2014 Paper

Developing a PLC-friendly state machine model: lessons learned

Wim Pessemier, Geert Deconinck, Gert Raskin, Philippe Saey, Hans Van Winckel

Proc. SPIE. 9152, Software and Cyberinfrastructure for Astronomy III

KEYWORDS: Telescopes, Logic, Data modeling, Control systems, Computer programming, Software development, Photonic integrated circuits, Optical proximity correction, Systems modeling, Standards development

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Modern Programmable Logic Controllers (PLCs) have become an attractive platform for controlling real-time aspects of astronomical telescopes and instruments due to their increased versatility, performance and standardization. Likewise, vendor-neutral middleware technologies such as OPC Unified Architecture (OPC UA) have recently demonstrated that they can greatly facilitate the integration of these industrial platforms into the overall control system. Many practical questions arise, however, when building multi-tiered control systems that consist of PLCs for low level control, and conventional software and platforms for higher level control. How should the PLC software be structured, so that it can rely on well-known programming paradigms on the one hand, and be mapped to a well-organized OPC UA interface on the other hand? Which programming languages of the IEC 61131-3 standard closely match the problem domains of the abstraction levels within this structure? How can the recent additions to the standard (such as the support for namespaces and object-oriented extensions) facilitate a model based development approach? To what degree can our applications already take advantage of the more advanced parts of the OPC UA standard, such as the high expressiveness of the semantic modeling language that it defines, or the support for events, aggregation of data, automatic discovery, ... ? What are the timing and concurrency problems to be expected for the higher level tiers of the control system due to the cyclic execution of control and communication tasks by the PLCs? We try to answer these questions by demonstrating a semantic state machine model that can readily be implemented using IEC 61131 and OPC UA. One that does not aim to capture all possible states of a system, but rather one that attempts to organize the course-grained structure and behaviour of a system. In this paper we focus on the intricacies of this seemingly simple task, and on the lessons that we’ve learned during the development process of such a “PLC-friendly” state machine model.

Proceedings Article | 18 July 2014 Paper

A good attitude towards improved space telescope observations

Tjorven Delabie, Gert Raskin, Bart Vandenbussche, Joris De Schutter

Proc. SPIE. 9151, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation

KEYWORDS: Astronomy, Stars, Detection and tracking algorithms, Cameras, Sensors, Databases, Satellites, Space telescopes, Algorithm development, Space operations

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Proceedings Article | 5 October 2012 Paper

MESA: Mercator scheduler and archive system

Florian Merges, Saskia Prins, Wim Pessemier, Gert Raskin, Jesus Perez Padilla, Hans Van Winckel, Conny Aerts

Proc. SPIE. 8451, Software and Cyberinfrastructure for Astronomy II

KEYWORDS: Human-machine interfaces, Observatories, Telescopes, Astronomy, Databases, Inspection, Data archive systems, Software development, Astrophysics, Computer programming languages

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Proceedings Article | 24 September 2012 Paper

Design and first commissioning results of PLC-based control systems for the Mercator telescope

Wim Pessemier, Geert Deconinck, Gert Raskin, Philippe Saey, Hans Van Winckel

Proc. SPIE. 8451, Software and Cyberinfrastructure for Astronomy II

KEYWORDS: Observatories, Telescopes, Mirrors, Electronics, Interfaces, Control systems, Computer programming, Space telescopes, Photonic integrated circuits, Optical proximity correction

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Proceedings Article | 24 September 2012 Paper

A new Nasmyth mirror mechanism increases the number of focal stations of the Mercator Telescope

Gert Raskin, Rene Dubosson, Bernard Michaud, Wim Pessemier, Hans Van Winckel

Proc. SPIE. 8446, Ground-based and Airborne Instrumentation for Astronomy IV

KEYWORDS: Observatories, Telescopes, Mirrors, Imaging systems, Magnetism, Control systems, Computer programming, Space telescopes, Servomechanisms, Photonic integrated circuits

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Proceedings Article | 24 September 2012 Paper

UAF: a generic OPC unified architecture framework

Wim Pessemier, Geert Deconinck, Gert Raskin, Philippe Saey, Hans Van Winckel

Proc. SPIE. 8451, Software and Cyberinfrastructure for Astronomy II

KEYWORDS: Observatories, Telescopes, Data modeling, Databases, Control systems, Software development, Photonic integrated circuits, Optical proximity correction, OLE for process control, Software frameworks

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Proceedings Article | 1 October 2011 Paper

MAIA: a multispectral instrument for asteroseismology observations of hot subdwarf stars

J. Vandersteen, G. Raskin, J. Morren, R. Østensen, W. Pessemier, S. Prins, J. Swevers, H. Van Winckel, C. Aerts

Proc. SPIE. 8172, Optical Complex Systems: OCS11

KEYWORDS: Telescopes, Beam splitters, Stars, Lenses, Cameras, Sensors, Collimators, Space telescopes, Charge-coupled devices, Cryocoolers

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Proceedings Article | 20 July 2010 Paper

MAIA: a rapid three-channel photometry CCD instrument for asteroseismology observations

J. Vandersteen, G. Raskin, T. Agócs, J. Morren, R. Østensen, W. Pessemier, S. Prins, J. Swevers, S. Tulloch, H. Van Winckel, C. Aerts

Proc. SPIE. 7735, Ground-based and Airborne Instrumentation for Astronomy III

KEYWORDS: Telescopes, Beam splitters, Stars, Cameras, Sensors, Collimators, Space telescopes, Charge-coupled devices, Photometry, CCD image sensors

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Proceedings Article | 19 July 2010 Paper

Towards a new Mercator Observatory Control System

W. Pessemier, G. Raskin, S. Prins, P. Saey, F. Merges, J. Padilla, H. Van Winckel, C. Waelkens

Proc. SPIE. 7740, Software and Cyberinfrastructure for Astronomy

KEYWORDS: Observatories, Telescopes, Astronomy, Computing systems, Control systems, Software development, Computer networks, Lanthanum, Data communications, Current controlled current source

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A new control system is currently being developed for the 1.2-meter Mercator Telescope at the Roque de Los Muchachos Observatory (La Palma, Spain). Formerly based on transputers, the new Mercator Observatory Control System (MOCS) consists of a small network of Linux computers complemented by a central industrial controller and an industrial real-time data communication network. Python is chosen as the high-level language to develop flexible yet powerful supervisory control and data acquisition (SCADA) software for the Linux computers. Specialized applications such as detector control, auto-guiding and middleware management are also integrated in the same Python software package. The industrial controller, on the other hand, is connected to the majority of the field devices and is targeted to run various control loops, some of which are real-time critical. Independently of the Linux distributed control system (DCS), this controller makes sure that high priority tasks such as the telescope motion, mirror support and hydrostatic bearing control are carried out in a reliable and safe way. A comparison is made between different controller technologies including a LabVIEW embedded system, a PROFINET Programmable Logic Controller (PLC) and motion controller, and an EtherCAT embedded PC (soft-PLC). As the latter is chosen as the primary platform for the lower level control, a substantial part of the software is being ported to the IEC 61131-3 standard programming languages. Additionally, obsolete hardware is gradually being replaced by standard industrial alternatives with fast EtherCAT communication. The use of Python as a scripting language allows a smooth migration to the final MOCS: finished parts of the new control system can readily be commissioned to replace the corresponding transputer units of the old control system with minimal downtime. In this contribution, we give an overview of the systems design, implementation details and the current status of the project.

Proceedings Article | 11 July 2008 Paper

HERMES: a high-resolution fiber-fed spectrograph for the Mercator Telescope

Gert Raskin, Hans Van Winckel

Proc. SPIE. 7014, Ground-based and Airborne Instrumentation for Astronomy II

KEYWORDS: Observatories, Telescopes, Spectrographs, Optical design, Prisms, Astronomy, Stars, Image resolution, Charge-coupled devices, Lanthanum

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Proceedings Article | 30 June 2006 Paper

Design of HERMES: a high-resolution fiber-fed spectrograph for the Mercator Telescope

Gert Raskin, Hans Van Winckel, Holger Lehmann

Proc. SPIE. 6269, Ground-based and Airborne Instrumentation for Astronomy

KEYWORDS: Telescopes, Mirrors, Spectrographs, Prisms, Stars, Cameras, Sensors, Calibration, Collimators, Charge-coupled devices

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Proceedings Article | 30 September 2004 Paper

Mercator and the P7-2000 photometer

Gert Raskin, Gilbert Burki, Michel Burnet, Geert Davignon, Rene Dubosson, Emile Ischi, Michel George, Michel Grenon, Charles Maire, Hans Van Winckel, Christoffel Waelkens, Luc Weber

Proc. SPIE. 5492, Ground-based Instrumentation for Astronomy

KEYWORDS: Observatories, Telescopes, Mirrors, Digital signal processing, Stars, Control systems, Signal processing, Photometry, Lanthanum, Filtering (signal processing)

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We present the Mercator Telescope together with the P7-2000 photometer as its first-light instrument. Mercator is a 1.2-meter Ritchey-Chretien telescope, installed at the Roque De Los Muchachos Observatory on La Palma and fully operational since Spring 2001. The Geneva Observatory developed this telescope and a twin, known as the Euler Telescope, was already inaugurated at the La Silla Observatory in 1998. Mercator is an alt-azimuthal telescope designed for semi-automatic operation and high operational robustness. P7 is a high-precision 2-channel differential photometer, built by the Geneva Observatory and in permanent use for over 25 years on various telescopes. It allows quasi-simultaneous observations in the 7 filters of the Geneva photometric system with a variable sampling rate up to 100 samples per second. This vintage instrument was completely refurbished in 2000 to function in an automatic mode on the Mercator Telescope. Electronics were completely renewed and are now based on a digital signal processor (DSP), which controls the instrument and performs basic data reduction. The optical system was left unmodified, apart from the addition of a field camera that is also used for auto-guiding. We also added instrument temperature control and a mechanical derotator. Since the 7 filters are acquired simultaneously and the absolute calibration of the colors is strictly homogeneous, the Mercator-P7 combination is a unique tool to study stellar variability on many different timescales. The current scientific program focuses on multi-periodic phenomena in early-type stars with the goal to identify the frequency spectrum and to constrain stellar models by asteroseismology studies. More than 43000 observations have been performed since 2001 and a precision of few milli-magnitudes is routinely achieved. Our photometric measurements result in the continuous calculation of the atmospheric extinction coefficients and these data are available online for other observers as well. In this paper, we describe the telescope, the photometer and their software, followed by the presentation of some first results. Finally, we discuss an upcoming upgrade and the complete instrumentation plan for Mercator.

Proceedings Article | 30 September 2004 Paper

HERMES: a high-resolution spectrograph for the Mercator Telescope

Gert Raskin, Hans Van Winckel, Geert Davignon

Proc. SPIE. 5492, Ground-based Instrumentation for Astronomy

KEYWORDS: Optical fibers, Telescopes, Mirrors, Spectrographs, Prisms, Stars, Cameras, Calibration, Interfaces, Charge-coupled devices

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Proceedings Article | 30 September 2004 Paper

CCD camera and automatic data reduction pipeline for the Mercator telescope on La Palma

Geert Davignon, Andre Blecha, Gilbert Burki, Fabien Carrier, Martin Groenewegen, Charles Maire, Gert Raskin, Hans Van Winckel, Luc Weber

Proc. SPIE. 5492, Ground-based Instrumentation for Astronomy

KEYWORDS: Observatories, Telescopes, Optical filters, Imaging systems, Cameras, Sensors, CCD cameras, Charge-coupled devices, Lanthanum, CCD image sensors

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