Sunrise III: Overview of Observatory and Instruments

Abstract

In July 2024, Sunrise completed its third successful science flight. TheSunrise iii observatory had been upgraded significantly after the two previous successfulflights in 2009 and 2013, to tackle the most recent science challenges concerning thesolar atmosphere. Three completely new instruments focus on the small-scale physicalprocesses and their complex interaction from the deepest observable layers in thephotosphere up to chromospheric heights. Previously poorly explored spectral regionsand lines are exploited to paint a three-dimensional picture of the solar atmosphere withunprecedented completeness and level of detail.The full polarimetric information is captured by all three instruments to reveal theinteraction between the magnetic fields and the hydrodynamic processes. Two slit-based spectropolarimeters, the Sunrise UV Spectropolarimeter and Imager (SUSI)and the Sunrise Chromospheric Infrared spectro-Polarimeter (SCIP), focus on thenear-ultraviolet (309–417 nm) and the near-infrared (765–855 nm) regions respectively,and the imaging spectropolarimeter Tunable Magnetograph (TuMag) simultaneouslyobtains maps of the full field-of-view of 46 × 46 Mm2 in the photosphere and thechromosphere in the visible (525 and 517 nm). The instruments are operated in anorchestrated mode, benefiting from a new Image Stabilization and Light Distributionunit (ISLiD), with the Correlating Wavefront Sensor (CWS) providing the autofocuscontrol and an image stability with a root-mean-square value smaller than 0.005”. Anew gondola was constructed to significantly improve the telescope pointing stability,required to achieve uninterrupted observations over many hours.Sunrise iii was launched successfully on 10 July 2024, from the Esrange Space Centerof the Swedish Space Corporation near Kiruna (Sweden). It reached the landing sitebetween the Mackenzie River and the Great Bear Lake in Canada after a flight durationof 6.5 days. In this paper, we give an overview of the Sunrise iii observatory and itsinstruments.