The Sunrise Chromospheric Infrared Spectro-Polarimeter SCIP: an instrument for SUNRISE III
astro-ph.SR
/ Authors
Y. Katsukawa, J. C. del Toro Iniesta, S. K. Solanki, M. Kubo, H. Hara, T. Shimizu, T. Oba, Y. Kawabata, T. Tsuzuki, F. Uraguchi
and 37 more authors
K. Shinoda, T. Tamura, Y. Suematsu, T. Matsumoto, R. T. Ishikawa, Y. Naito, K. Ichimoto, S. Nagata, T. Anan, D. Orozco Suárez, M. Balaguer Jiménez, A. C. López Jiménez, C. Quintero Noda, D. Álvarez García, J. L. Ramos Mas, B. Aparicio del Moral, A. Sánchez Gómez, D. Hernández Expósito, E. Bailón Martínez, J. M. Morales Fernández, A. J. Moreno Mantas, A. Tobaruela
/ Abstract
The Sunrise balloon-borne solar observatory is equipped with a one-meter aperture optical telescope, offering a unique platform for uninterrupted seeing-free observations across ultraviolet, visible, and infrared wavelengths from altitudes higher than 33 km. For the third flight of the upgraded Sunrise observatory conducted in 2024, now called Sunrise III, a new spectro-polarimeter called the SCIP was developed for observing near-infrared wavelength ranges around 770 nm and 850 nm. These wavelength ranges contain many spectral lines, including two of the Ca II infrared triplet, K I D1 and D2 lines, and multiple Fe I lines, that are sensitive to solar magnetic fields and velocities in the photosphere and chromosphere. Polarimetric measurements are conducted using a rotating waveplate as a modulator and polarizing beam splitters in front of the cameras. The spatial and spectral resolutions are 0.21" and 2x10^5, respectively, and a polarimetric sensitivity of 0.03% (1sigma) of the continuum intensity is achieved within a 10 s integration time. To detect small polarization signals with good precision, we carefully designed the opto-mechanical system, polarization optics and modulation, control electronics, and onboard data processing. Together with the other post-focus instrumentation developed for Sunrise III, the Sunrise Ultraviolet Spectropolarimeter and Imager and the visible imaging spectro-polarimeter Tunable Magnetograph, SCIP provides novel and unique observations to understand the energy transfer and dynamical processes through the photosphere-chromosphere.