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2026 observing campaign The call for the 2026 observing campaign is now closed! THEMIS 2026 observing campaign will take place approximately from early September to mid-November, 2026, lasting for about 70 days. The 1st half of 2026 shall be mostly dedicated to the on-going installation and commissioning of the Italian IBIS 2.0 spectro-imager. 2026 campaign schedule The 2026 campaign shall observe the following schedule: December 16th, 2025: opening of call to apply for 2026 observation. See bellow for how to apply. January 21st, 2026: proposal deadline for “Spanish time” observers Friday February 13th, 2026: proposal deadline for “French time” & “International time” observers March 2026: observation time allocation announced to applicants 2026 campaign schedule v1.0 ( Graphics (pdf) ; List (pdf) ; cf. images on the right) - status: preliminary : do not make any travel reservation at this time ! </color> * Spring 2026: commissioning of the IBIS 2.0 spectro-imager * September to mid-November 2026: observation campaign ==== Call for observation time during the 2026 campaign (open) ==== Interested researchers are encouraged to check the available instrumentation for 2026, the information on THEMIS observing capacities, as well as the available data products. Inquiries : Applicants, in particular if they are not familiar with THEMIS observations, are encouraged to contact the THEMIS staff — in particular email themis.team@themis.iac.es —- directly to obtain more specific information or express their needs. Given the smaller amount of international time, interested international researchers can also contact the THEMIS staff to discuss possible joint campaign with French applicants, in case compatible observation targets/mode are envisioned. === How to apply === The submission of proposals is specific to the category of users one belongs, based on rules of access: * “French time”: ~75% of the campaign, 52 days in 2026. * Interested observers shall complete the LaTex application form (PDF preview) and e-mail it to: themis.team@themis.iac.es. * Deadline: Friday February 13th, 2026. * “Spanish time”: 20% of the campaign, 14 days for 2026. * Applicants shall follow the instructions of the IAC solar CAT proposal system. * Deadline: January 21st, 2026. * “International time”: ~5% of the total, or 3 days in 2026. * Interested observers shall complete the LaTex application form (PDF preview) and e-mail it to: themis.team@themis.iac.es. * Deadline: Friday February 13th, 2026. As soon as the appropriate proposal refereeing procedures of each community and TAC have been passed, applicants shall quickly be informed of their application outcomes. During the spring of 2026, the integration of IBIS 2.0 being scheduled only a limited observation slots are possible. Users requiring observation time during this period shall provide specific justifications based on strong scientific arguments.

Preliminary 2026 Campaign schedule: */

==== Available instrumentation for 2026 ==== === Adaptive optics === TAO is available and tested over sunspots and granulation with good results over significantly long periods of time (seeing dependent). * A slowed-down (100Hz) version of the same system can be used to stabilize Mercury. * While it is not possible to use TAO over the solar limb (or for neighboring prominences), during the 2025 campaign, tests have been carried to observe prominences while TAO was focused on granulation in an offset disc region of THEMIS FOV. Even though the TAO isoplanatic region is located far from the targeted prominence, TAO nonetheless provided significant improvements, as shown in the August THEMIS image of the month. === MTR2 in spectroscopy mode === In this mode, up to 4 EMCCD Andor iXon cameras (512×512 pixels) and up to 2 (recent) Andor Zyla (2kx2k pixels) cameras are available. All 6 cameras can be setup and used at the same time (with their respective specifications), in accordance with the SP2 output physical limitations. More information about the MTR2 spectrograph. === MTR2 in spectropolarimetry mode: === THEMIS polarimetric analysis scheme is based on a full-Stokes analyzer located at the F1 prime focus. For any solar polarization state to measure, the output of the analyzer is made of dual superimposed complementary linear polarizations. Thanks to THEMIS “polarization friendly” new optical scheme, this output travels through the telescope and arrives unperturbed on the spectrograph cameras (cf. information about MTR2 spectrograph). Just in front of the camera, a Wollaston splitter separates the beam into complementary Stokes components to form the spectral focal plane. THEMIS own three Wollaston, hence 3 cameras/3 wavebands at most can be simultaneously observed with polarimetric signal, among the 6 spectral cameras that THEMIS proposes. It is however possible to combine polarimetric and non-polarimetric cameras. Regarding the available analysis software: === Broadband imaging (BBI) context camera: === THEMIS BBI fast camera (40 frames/s), is running concurrently with the spectrograph. Current setup is for the continuum around 656 nm (red), but can be optionally changed to G-band or other. === Available analysis softwares === * Knox-Thompson image reconstruction for BBI * Reconstructed spectral map quick-looks for on site analysis, to be adapted to specific wavelength. * Stokes map quick-looks * Thanks to V. Bommier, a basic magnetic field inversion software package (running locally in IDL) is also available. /* == 2024 known problems (and solutions) == * The optical diffusion problem that was detected in Sept 2024 (mostly affecting the He D3 observations) has been identified and corrected (November 2024). * The data acquisition issue in polarimetric modes was tracked down to a bad synchronisation between the analyzer rotation and the camera exposure. This has been solved at the cost of slowing down the acquisition loop (roughly a factor 2 slower). This issue has been affecting all the September 2024 runs. */