Differences

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

--- themis [2025/09/08 16:58] – etienne
+++ themis [2025/11/07 10:18] (current) – etienne
@@ Line 13: / Line 13: @@
 */
-<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]]**
 <newcolumn 30%>
-/*<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> */
@@ Line 66: / Line 66: @@
 === Observing with THEMIS  ===
 **[[observation| Information for research scientists wishing to observe with THEMIS]]** \\
-**[[observation:2025campaign#2025 campaign schedule | Schedule of 2025 observing campaign]]** \\
+[[observation:2025campaign | 2025 observing campaign]] \\
 [[observation:weather | Weather at THEMIS location and weather forecast]] \\
 [[observation:data| THEMIS data products & data access]]
@@ Line 76: / Line 76: @@
-== THEMIS image of the month: August 2025 ==
+== THEMIS image of the month: October 2025 ==
+<columns 100% l 40>
+<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:instrumentation:themisthroughoculus.jpg
+"> <img src="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:instrumentation:themisthroughoculus.jpg
+" alt="THEMIS telescope through the dome oculus" style="width: 100%; height: auto;"></a></html> \\
-=== August 2025 ===
+<newcolumn 60%>
-<columns 100% l 60>
-<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:protu:limbprominenceobservation_20250506_withandwithoutao.jpg
-"> <img src="https://www.themis.iac.es/lib/exe/fetch.php?media=science:gallery:protu:limbprominenceobservation_20250506_withandwithoutao.jpg
-" alt="Prominence Halpha observations at limb: Adaptive Optics comparison" style="width: 100%; height: auto;"></a></html> \\
+A view of the THEMIS telescope in its resting safe position seen through the oculus of the dome. The THEMIS dome was designed not only to protect the telescope from inclement weather, but also to avoid direct sunlight heating the floor around the telescope mount. Such heat induces turbulence that can significantly impact the quality of the observations. In order for THEMIS to observe, the oculus has precisely the size of the telescope aperture. While observing the only sunlight that gets in the dome goes in the telescope. Both the telescope and the oculus must then move smoothly and synchronously when tracking the Sun during its diurnal motion.
-<newcolumn 40%>
-During the 2025 observation campaign of Brigitte Schmieder and Arek Berlicki, THEMIS targeted a small prominence. Prominence are emitting structures that can be observed at the solar limb, beyond the outer edge of the Sun's disk. Prominences and filaments are two aspects of an unique physical feature: a domain of cold chromosphere like plasma, magnetically confined in the much hotter solar corona. While this structure appears as dark when seen in contrast with the disk, and is then called a filament, it appears bright in contrast to the plane of sky. As a magnetised structure filament/prominence can erupt, releasing plasma and material toward the solar system. Understanding how the magnetic structure them is fundamental to comprehend their stability or lack off.
-THEMIS is mainly a [[technical:mtr2 | scanning spectrograph instrument]], i.e. a very thin slit scans the region of interest, in order to obtain high resolution spectrograms. THEMIS images are thus reconstructed. While scanning, THEMIS is thus very sensitive to the effect of turbulence and the reconstructed image have necessarily a lower resolution that direct imaging. On the other hand, THEMIS can deliver simultaneous images at different wavelength.
-\\
 </columns>
-While adaptive optics can generally be used to significantly improve on disc observations, such as with our own [[technical:tao|Themis AO]], AOs fail when trying to observe over the limb because no structure there can be tracked by the AO. Recently our colleagues of the U.S. National Science Foundation National Solar Observatory and New Jersey Institute of Technology, observed [[https://nso.edu/press-release/new-adaptive-optics-shows-stunning-details-of-our-stars-atmosphere/ | beautiful prominence dynamics]] with the Goode Solar Telescope thanks to their [[https://www.nature.com/articles/s41550-025-02564-0 |new coronal adaptive optics]] in a direct imaging approach.
-At THEMIS, during our 2025 campaign we tried a different approach. While we were scanning a prominence at the limb, we use TAO on an offset region which is close to the limb while still on the disc. TAO is a simple AO which isoplanatic region (region where most of the AO correction is done) is limited. Since the isoplanatic region and the region of scientific interest are far away, the AO correction may be limited at the prominence. We were however very please to see that TAO still provide significant improvements. As can be seen in this image of the month, the turbulence induced motions (in the direction of the slit) which are present when TAO is off, are strongly reduced when TAO is switched on. The limb appears much smoother and the prominence better resolved.