Differences

This shows you the differences between two versions of the page.

--- themis [2025/08/12 16:11] – etienne
+++ themis [2025/10/15 11:13] (current) – etienne
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-<color red >   ** New :** </color>
+<color red >   ** New :** </color> [[science:results:SeminLPP | October : Seminar on THEMIS at the Plasma Physics Laboratory, Paris (FR).]] \\
+\\
 [[science:resources | Downloadable posters highlighting recent high-resolution observations of solar active regions by THEMIS]]\\
-[[science:results:ESTFrance2025 | June : Presentation of THEMIS results at the EST France 2025 Workshop in Paris (FR).]] \\
-[[science:results:SF2A2025 | July : Presentation of THEMIS results at the "Journées de la SF2A" in Toulouse (FR).]] \\
 Click for information on: \  \  **[[admin:location| How to reach THEMIS locations]]** \ ; \ **[[admin:contacts| How to contact the THEMIS team]]**
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-/*<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=observatorio_del_teide_daniel_lopez-6_sm.jpg"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=observatorio_del_teide_daniel_lopez-6_sm.jpg" style="width:90%; height: auto;"></a></html>*/
+<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=observatorio_del_teide_daniel_lopez-6_sm.jpg"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=observatorio_del_teide_daniel_lopez-6_sm.jpg" style="width:90%; height: auto;"></a></html>
 /*WINTER PIC*/
-/*<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:dsc7357.jpg"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=dsc7357.jpg" style="width:90%; height:auto;"></a></html>*/
+/*<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=sciencedsc7357.jpg"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=dsc7357.jpg" style="width:90%; height:auto;"></a></html>*/
-/* SPRING PIC */
+/* SPRING PIC
-<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=themis_spring25.jpg"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=themis_spring25.jpg" style="width:90%; height:auto;"></a></html>
+<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:building:themis_spring25"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:building:themis_spring25.jpg" style="width:90%; height:auto;"></a></html> */
+/* NIGHT PIC
+<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:building:img_4553-jpg.jpg"><img src="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:building:img_4553-jpg.jpg" style="width:90%; height:auto;"></a></html> */
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-== THEMIS image of the month: July 2025 ==
+== THEMIS image of the month: September 2025 ==
-<columns 80% l >
+<columns 100% l 60>
+<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:schema:opticalpath_tao.png
+"> <img src="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:schema:opticalpath_tao.png
+" alt="Diagram of THEMIS adaptive optic light-path." style="width: 100%; height: auto;"></a></html> \\
-=== July 2025 ===
+<newcolumn 40%>
-<columns 100% l >
-<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:instrumentation:spectro_with_light.png"> <img src="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:instrumentation:spectro_with_light.png" alt="A peek inside THEMIS MTR2 spectrograph" style="width: 40%; height: auto;"></a></html> \\
-If one could sneak inside [[technical:mtr2 | 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. \\
+THEMIS design, laid out in the 1980's, predate the revolution of adaptive optics (AO), and hence didn't foresee its installation. AO has since proved to be an indispensable technology of all modern high-resolution telescope. The core of the THEMIS overhaul that took place in the second half of the 2010's had the installation of a simple AO at the core of its objective.
-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.
+The installation of the [[technical:tao|THEMIS AO]] was thus particularly challenging as it required to deal with the limited existing available space. The entry prism is thus located just inside the spectrograph container, close to its roof, in a location that is not easily accessible. In addition, as shown in the diagram of TAO, it imposed to place the wavefront sensor optical bench (as well as the scanning mirror) outside of the THEMIS spectrograph container, in a vertical layout.
-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 [[https://www.themis.iac.es/doku.php?id=science:objectives | diverse topics in solar physics]].
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