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We're happy if you're able to use our data for your scientific purposes. If you publish any work using our data, please cite and acknowledge us! We've listed detailed instructions for each instrument below.


Using GRIS Data

If you use GRIS data for your work, acknowledge the GRIS and GREGOR projects with these citations and include the following paragraph in your acknowledgments:

The 1.5-meter GREGOR solar telescope was built by a German consortium under the leadership of the Leibniz Institut für Sonnenphysik (KIS) in Freiburg with the Leibniz-Institut für Astrophysik Potsdam, the Institut für Astrophysik Göttingen, and the Max-Planck Institut für Sonnensystemforschung in Göttingen as partners, and with contributions by the Instituto de Astrofisica de Canarias and the Astronomical Institute of the Academy of Sciences of the Czech Republic. The GRIS instrument was developed thanks to the support by the Spanish Ministry of Economy and Competitiveness through the project AYA2010-18029 (Solar Magnetism and Astrophysical Spectropolarimetry).

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.


Collados et al.2012GRIS: The GREGOR Infrared Spectrograph
Kleint et al.2020GREGOR: Optics redesign and updates from 2018–2020
(Cite for data newer than 2020)
Schmidt et al.2012The 1.5 meter solar telescope GREGOR
(Cite for data older than 2020)
Borrero et al.2011VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager
(Cite if data from inversions is used)
A. J. Kaithakkal2019Evolution of Stokes V area asymmetry related to a quiet Sun cancellation observed with GRIS/IFU

Using LARS Data

If you use LARS data for your work, please use these citations and include the following paragraph in your acknowledgments:

The Vacuum Tower Telescope at the Observatorio del Teide on Tenerife is operated by the Leibniz Institute for Solar Physics (KIS) Freiburg, which is a public law foundation of the State of Baden-Württemberg and a member of the Leibniz-Gemeinschaft. The installation and characterization of LARS at the VTT had been funded by the Leibniz-Gemeinschaft from 2011 to 2014 through the "Pakt für Forschung und Innovation". The initial characterization of the Laser frequency comb at the VTT was based on an agreement between the Max-Planck-Institute for Quantum Optics (Garching) and the KIS. The scientific exploitation of LARS was supported by the Deutsche Forschungsgemeinschaft under grant Schm-1168/10 between 2016 and 2018.

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).


Löhner-Böttcher et al.2017LARS: An Absolute Reference Spectrograph for solar observations. Upgrade from a prototype to a turn-key system
Doerr H.2015Precision spectroscopy with a frequency-comb-calibrated solar spectrograph
Löhner-Böttcher et al.2018Convective blueshifts in the solar atmosphere I
Stief et al.2019Convective blueshifts in the solar atmosphere II
Löhner-Böttcher et al2019Convective blueshifts in the solar atmosphere III

Using ChroTel Data

If you use ChroTel data for your work, please use these citations. ChroTel Data is freely available for scientific and educational use. Published work based on ChroTel data should include an acknowledgement like:

ChroTel is operated by the Leibniz Institute for Solar Physics (KIS), Freiburg, Germany, at the Spanish Observatorio del Teide, Tenerife, Canary Islands. The ChroTel filtergraph has been developed by the Kiepenheuer-Institute in co-operation with the High Altitude Observatory in Boulder, CO, USA.

ChroTel is a 10 cm aperture telescope to observe the chromosphere of the Sun. It was developed at the Leibniz-Institut for Solar Physics (KIS) Freiburg together with the High Altitude Observatory (HAO) in Boulder, USA. With a spatial resolution of about 2 arcsec it observes the solar chromosphere in its most prominent lines un the near UV, the red and the infrared (Ca II K, Hα and He I) using a 2048x2048 pixel CCD. ChroTel uses a two mirror system ("turret") next to the VTT building that relays a stabilized image of the solar disc into a laboratory within the VTT building. The heart of the optical lab is a filter system consisting of three narrow-band Lyot filters, of which one is tunable. The He I filter is tunable and observations are taken at seven wavelength positions fully covering the whole spectral line, giving full-disk chromospheric Doppler maps. Images in all channels (and the seven He I bands) can be taken with a cadence of below one minute. The operation of ChroTel is automatic, as far as possible. ChroTel also serves live images for VTT and Gregor. The scientific data of ChroTel are freely available for scientific and educational use. Observing campaigns together with the Tenerife Infrared Polarimeter (TIP) at the VTT enabled us to calibrate the Doppler shift maps derived from the seven filtergrams of ChroTel in the Helium I channel. The main goals of the science operations of ChroTel are to study the dynamic response of the chromosphere to photospheric driving especially in the chromospheric network, large-scale structures and their disturbance such as flares and CMEs and the chromospheric source of the fast solar wind. An overview of the available data products and the header structure of the individual fits files can be found here.


Kentischer et al. et al.2008ChroTel: a robotic telescope to observe the chromosphere of the Sun
Bethge et al.2011The Chromospheric Telescope