Interested researchers are encouraged to check the available instrumentation for 2025, 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.

The submission of proposals is specific to the category of users one belongs, based on rules of access:

• “French time”: 75% of the campaign, 75 days in 2025.

  • Interested observers shall complete the LaTex application form and e-mail it to: themis.team@themis.iac.es.
  • Deadline: February 17th, 2025.
• “Spanish time”: 20% of the campaign, 20 days for 2025.

  • Applicants shall follow the instructions of the IAC solar CAT proposal system.
  • Deadline: January 24th, 2025.
• “International time”: 5% of the total, or 5 days in 2025.
  

  • Interested observers shall complete the LaTex application form and e-mail it to: themis.team@themis.iac.es.
  • Deadline: February 17th, 2025.

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 fall of 2025, 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 scientific reasons.

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.
• At the moment it is not possible to use the AO over the solar limb (or for neighboring prominences).

In this mode, up to 4 (old) EMCCD Andor iXon camera (512×512) and up to 2 (new) Andor Zyla (2kx2k) cameras are available. Both 6 cameras can be setup and used at the same time (with their respective specs), in accordance with the SP2 output physical limitations.

In this mode, 3 cameras (hence 3 wavelengths) at most are available, from the above list. It is possible to combine polarimetric and non-polarimetric cameras. 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. Just in front of the camera, a Wollaston splitter separates the beam into complementary Stokes components to form the spectral focal plane.

Regarding the available analysis software:

• A Stokes map quick-look is now available.
• Thanks to V. Bommier, a basic magnetic field inversion software package (running locally in IDL) is available.

It is running concurrently with the spectrograph. Current setup is for 656 nm (red), but this can be changed optionally to G-band or other.

• 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.

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