This work package combines several instrument development projects to improve the existing solar telescopes and with a perspective to application in future large aperture solar telescopes. There are two projects pursuing solar field-integrated spectroscopy (the combination of high spectral dispersion with a diffraction-limited two-dimensional field of view), and which have already passed the prototype stage. The goal is to develop facility instruments implementing these concepts on existing telescopes, which requires substantial development. The concepts are based on image slicers for 2D spectroscopy and micro-lens based bi-dimensional spectroscopy. Both concepts have been realized for applications in night-time telescopes, so there is an inheritance which is being exploited for the purposes of solar observations. Both concepts are also relevant for application in EST.
A third project will develop design concepts for a narrow-band tunable-filter Imager for EST. The main challenge is the large optical throughput required for the key elements – the etalons – which result from the combination of a 4m aperture and a useful field size. The fourth project will develop a new method for very high precision absolute polarization measurements at the IRSOL telescope in Switzerland, with a perspective for migration to a larger telescope like GREGOR. This new capability addresses directly a key science goal of EST. This work package combines the competences of 11 partners.