Thematic Groups: PEPS et PS2E
Scientific Leader: Frédéric Pitout
Main OSU: Observatoire Midi-Pyrénées

Contexte / Background

CLIMSO is a National Observation Service (SNO) labeled in the national action of observations ANO 6 “Monitoring of the Sun and the space environment of the Earth” by the National Institute of Sciences of the Universe (INSU).

CLIMSO consists of four instruments dedicated to solar observation installed at the Pic du Midi observatory.
Two telescopes take images of the solar disk through filters Hα (656.28 nm) and CaK (393.37 nm); these telescopes are used to locate filaments and magnetically active zones.
Two coronographs give access to the solar protuberances through filters Hα and HeI (1083.0 nm).

Scientific Objectives

How is the corona, the outermost envelope of the solar atmosphere, heated to some 2 MK when the solar photosphere (the surface, so to speak) is only about 6000 K? How is the solar wind accelerated? How do the cycles of solar activity that vary in intensity cycle after cycle evolve? Can we predict the coronal mass ejections that can reach the Earth and disrupt our technologies (space weather)? In order to contribute to advances in these fields, Climso intervenes in several ways.

In synoptic observation mode first. The aim is to monitor solar activity and to build a database covering the longest possible period since the 1970s. CLIMSO follows on from previous instruments such as the “petit coronographe” and the Haco coronograph. More specific uses are also in progress. For example, since 2020, CLIMSO has been identified as a participant in the ground support of the Parker Solar Probe mission, notably for coordinated observations during perihelion flights.

Finally, Climso is also used as a test bench for instrumentation.

Arturo López Ariste, researcher at IRAP, has tested a process to image the hot corona through a Fe-XIII filter and a “tip tilt” process which consists in taking images several times per second alternately of the corona and the sky background to subtract the second from the first and obtain a favorable contrast ratio to make the corona emerge from the blinding sunlight.

Involvement of IRAP

IRAP provides scientific responsibility and data archiving.


The Association of Associated Observers (OA), which ensures all the observations, is funded by a sponsor, Fiducial.
On the institutional side, the SNO is supported by INSU, via the National Sun-Earth Program (PNST), and the Midi-Pyrénées Observatory (OMP).