THEMIS Solar Telescope

If one could sneak inside MTR2 spectrograph while THEMIS is observing, this is what one would see looking down. The picture shows the beautiful work of decomposing the white solar light into small ranges of electromagnetic spectrum that are of interest for researchers to study the physical properties of the Sun.

The white light beam coming from the THEMIS telescope (white light on the left) is first decomposed in a low resolution spectrum (rainbow on the middle left). A rigid mask placed on the light path, enables to select several bands within the solar spectrum that will be analysed (overlapping orange and red patch on the middle right). Finally, an echelle grating enables to strongly increase the dispersion (spacing) of the spectral domains of interest (separated and extended red and orange patch on the right). There spectral cameras are placed to record the high resolution spectrum.

With its a spectral resolving power, R, of about 200 000-300 000, THEMIS MTR2 spectrograph has one of the world's best resolving power in astrophysics. MTR2 has the ability to distinguish between two wavelengths separated by a small amount. THEMIS theoretical can produce simultaneously up to eight high resolution spectrograms (although most cases, only 2-4 are requested). The choice of wavelength domains is not pre-imposed to the visiting research scientist observing with THEMIS. The choice is left to the investigators, giving them a high level of freedom to study diverse topics in solar physics.