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Our contribution intends to present the obtained performances of the NƎSIE instrument, a new near-infrared fiber-fed spectrograph developed at the University of Liege. This instrument was developed, aligned and tested at the Centre Spatial de Liege and first light was achieved in October 2017. This paper will go through the alignment process and optical performance verification to eventually introduce the first light observations. The final location of NƎSIE will be the TIGRE telescope located in La Luz, Mexico. The observational data provided by this instrument will help several research groups from the University of Liege to study massive stars. In particularly, evolution models will be improved through the comparison of the collected spectra with theoretical models. This collaboration will therefore contribute to a better understanding of massive stars and the mechanisms that take place within these extraordinary objects.

The ICON mission is led by the University of California-Berkeley (Space Sciences Laboratory). In the frame of this mission the Space Center of Liege was involved in the optical design optimization and related analysis, and VUV on ground calibration.

This paper presents the current status of ASPIICS, a solar coronagraph that is the primary payload of ESA’s formation flying in-orbit demonstration mission PROBA-3. The “sonic region” of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) is designed as a classical externally occulted Lyot coronagraph but it takes advantage of the opportunity to place the external occulter on a companion spacecraft, about 150m apart, to perform high resolution imaging of the inner corona of the Sun as close as ~1.1 solar radii. The images will be tiled and compressed on board in an FPGA before being down-linked to ground for scientific analyses. ASPIICS is built by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent development status of the ASPIICS instrument as it is approaching CDR.

ICON FUV is a two channel spectrographic imager that measures intensity and spatial distribution of oxygen (135.6 nm) and molecular nitrogen (157 nm) of the ionosphere. As those wavelengths are strongly absorbed by the atmosphere, the optical elements of the system have to be tested inside vacuum chambers. Prior to the instrument alignment and calibration, two 3600 gr/mm gratings were characterized. The primary focus is the measurement of the diffraction efficiencies; while the second objective is to select the best grating and to define which is the flight and the spare. A dedicated setup has been developed to assess the grating optical performances under vacuum. A 1 cm diameter collimated beam is generated using an off-axis parabola and a UV source at its focal point. The grating is placed at the center of two rotation stages collinearly aligned. One detector is placed on a rotating arm, deported from its rotation center. A PMT detector records diffracted light intensity with respect to its angular position and its wavelength. Angular incidence on the grating is tuned with the help of the second rotation stage. The grating efficiency homogeneity and scattering properties are measured through a Y-X scan.

The optical calibration of the ICON-FUV instrument requires designing specific ground support equipment (GSE). The ICON-FUV instrument is a spectrographic imager that operates on two specific wavelengths in the UV (135.6 nm and 157 nm). All the operations have to be performed under vacuum UV light. The optical setup is based on a VUV monochromator coupled with a collimator that illuminates the FUV entrance slit. The instrument is placed on a manipulator providing fields pointing. Image quality and spectral properties can be then characterized for each field. OGSE, MGSE, optical calibration plan and vacuum alignment of the instrument are described.

The "sonic region" of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The proposed PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), with its novel design, will be the first space coronagraph to cover the range of radial distances between ~1.08 and 3 solar radii where the magnetic field plays a crucial role in the coronal dynamics, thus providing continuous observational conditions very close to those during a total solar eclipse. PROBA-3 is first a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future European missions, which will fly ASPIICS as primary payload. The instrument is distributed over two satellites flying in formation (approx. 150m apart) to form a giant coronagraph capable of producing a nearly perfect eclipse allowing observing the sun corona closer to the rim than ever before. The coronagraph instrument is developed by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent improvements and design updates of the ASPIICS instrument as it is stepping into the detailed design phase.

PROBA-3 is a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future ESA missions. PROBA-3 will fly ASPIICS (Association de Satellites pour l’Imagerie et l’Interferometrie de la Couronne Solaire) as primary payload, which makes use of the formation flying technique to form a giant coronagraph capable of producing a nearly perfect eclipse allowing to observe the sun corona closer to the rim than ever before. The coronagraph is distributed over two satellites flying in formation (approx. 150m apart). The so called Coronagraph Satellite carries the camera and the so called Occulter Satellite carries the sun occulter disc. This paper is reviewing the design and evolution of the ASPIICS instrument as at the beginning of Phase C/D.

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument for stellar astrophysics. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s efficiency. Then the verification of predicted optical performances is investigated through optical analyses, such as resolution checking. Eventually, the star positioning system onto the central fiber core is explained.

In our contribution, we outline the different steps in the design of a fiber-fed spectrographic instrument that intends to observe massive stars. Starting from the derivation of theoretical relationships from the scientific requirements and telescope characteristics, the entire optical design of the spectrograph is presented. Specific optical elements, such as a toroidal lens, are introduced to improve the instrument’s performances. Then, the verification of predicted optical performances is investigated through optical analyses such as resolution checking. Eventually, the star positioning system onto the central fiber core is explained.