The GREGOR infrared spectrograph ( GRIS, Collados et al. 2012, AN 333, 872) provides high resolution spectropolarimetric data of features on the sun. Data older than one year is open for anyone to use. Current public data includes more than 500 data sets recorded from 2014 onward. Most observations are single raster scans recorded in spectropolarimetric mode in the 1.08µm and 1.56µm wavelength bands. Some of them are measurements in spectroscopic mode, time sequences capturing the evolution of solar features, or observations in other wavelength bands such as 2.2µm. We further provide overview maps and context data for each calibrated data is science-ready and can be downloaded directly from the archive. Further information on the GREGOR Telescope (GREGOR, Schmidt et al. 2012, AN 333, 796S) and GRIS can be found on our website or in the respective publications.

LARS, the Laser Absolute Reference Spectrograph of the Leibniz-Institut for Solar Physics is a scientific instrument for the ultramodern observation of the Sun at the Vacuum Tower Telescope (VTT) at the Observatorio del Teide on Tenerife. LARS enables the measurement of the solar spectrum of a selected field-of-view with the high-resolution Echelle-spectrograph of the VTT. Additionally, the emission spectrum of the newly installed Laser Frequency Comb is superimposed with the solar spectrum. Since each emission peak of the comb spectrum represents one well-defined frequency, the solar spectrum can be calibrated on an absolute wavelength scale. Figuratively, the comb serves as a ruler for the spectral lines. The accuracy is of the order of m/s or below and is therefore a multiple better than former devices. After the invention of the Laser Frequency Comb, awarded in 2005 with the Nobel Prize in Physics, the first astrophysical Frequency Comb was realized in 2008 at the VTT. The successful upgrade of the system in May 2016 by MenloSystems enables the continuous operation of this worldwide unique spectroscopic observation of the Sun. Since then, we have performed several successful observing campaigns focused on the convective blueshift in the solar atmosphere and on motions in sunspot umbrae. The results were published in a series of papers (see below).