Sunrise: A 1-M balloon borne solar telescope

Sunrise is a light-weight solar telescope with aim aperture for spectro-polarimetric observations of the solar atmosphere. The telescope is planned to be operated during a series of long-duration balloon flights in order to obtain time series of spectra and images at the diffraction-limit and to study the UV spectral region down to ≃ 200 nm, which is not accessible from the ground. The central aim of Sunrise is to understand the structure and dynamics of the magnetic field in the solar atmosphere. Interacting with the convective flow field, the magnetic field in the solar photosphere develops intense field concentrations on scales below 100 km, which are crucial for the dynamics and energetics of the whole solar atmosphere. In addition, Sunrise aims to provide information on the structure and dynamics of the solar chromosphere and on the physics of solar irradiance changes.