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--- themis [2025/03/01 10:42] – etienne
+++ themis [2025/09/08 16:58] (current) – etienne
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-The THEMIS solar telescope ("Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires") of [[https://www.insu.cnrs.fr/en|CNRS-INSU]] is a 1-meter-class optical solar telescope, primarily dedicated to studying solar magnetism and the dynamical processes within the Sun’s atmosphere (such as sunspots and solar flares). THEMIS can also perform observation of near-Sun objects such as Mercury and comets.
+The "Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires" (THEMIS) of [[https://www.insu.cnrs.fr/en|CNRS-INSU]] is a 1-meter-class optical solar telescope, primarily dedicated to studying solar magnetism and the dynamical processes within the Sun’s atmosphere (such as sunspots and solar flares). THEMIS can also perform observation of near-Sun objects such as Mercury and comets.
 THEMIS is located at the [[https://www.iac.es/en/observatorios-de-canarias/teide-observatory | Teide Observatory]] of [[https://www.iac.es/en | IAC]], with a base office in La Laguna, in Tenerife, Canary Islands, Spain.
-Click for information on: \  \  **[[admin:location| How to reach THEMIS locations]]** \ ; \ **[[admin:contacts| How to contact the THEMIS team]]**
 /*
 ;#;
-<color red > ** ¡¡¡ Call for the [[observation:2025campaign | 2025 observing campaign]] is open !!! ** \\
+<color red > 2025 campaign schedule ** ¡¡¡ Call for the [[observation:2025campaign | 2025 observing campaign]] is open !!! ** \\
 Deadline for "French" and "International" time" : February 17th, 2025. </color>
 ;#;
 */
+<color red >   ** New :** </color>
+[[science:resources | Downloadable posters highlighting recent high-resolution observations of solar active regions by THEMIS]]\\
+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>*/
+/*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>*/
+/* 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=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>
-/*{{observatorio_del_teide_daniel_lopez-6_sm.jpg?0x180|THEMIS and El Teide}}*/
 </columns>
 === Overview of telescope status  ===
-<columns 90% c 20% c 20% c 20% c 20% c 20% >
+<columns 100% c 20% c 20% c 20% c 20% c 20% >
 <html> <a href="http://themis.iac.es/wdata/Webcam/webcam.jpg"><img src="http://themis.iac.es/wdata/Webcam/webcam.jpg" style="width:90%; height: auto;"></a></html> \\
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 === Observing with THEMIS  ===
 **[[observation| Information for research scientists wishing to observe with THEMIS]]** \\
+**[[observation:2025campaign#2025 campaign schedule | Schedule of 2025 observing campaign]]** \\
 [[observation:weather | Weather at THEMIS location and weather forecast]] \\
 [[observation:data| THEMIS data products & data access]]
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 **[[science| Scientific research with THEMIS]]** \\
 [[science:results| THEMIS scientific highlights and news]] \\
-[[science:results:gallery| THEMIS observations and media galleries]]
+[[science:gallery| THEMIS observations and media galleries]]
-== THEMIS image of the month: March 2025 ==
+== THEMIS image of the month: August 2025 ==
+=== August 2025 ===
+<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> \\
+<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 70% l >
-<html> <a href="https://www.themis.iac.es/lib/exe/fetch.php?media=results:gallery:ar:noaa13981_c3flare_20250206_113010.jpg"> <img src="https://www.themis.iac.es/lib/exe/fetch.php?media=results:gallery:ar:noaa13981_c3flare_20250206_113010.jpg" alt="Themis NOAA 13981 during C3.3-class flare" style="width: 100%; height: auto;"></a></html>
 \\
-THEMIS observations of the east sunspot group of the active region NOAA 13981 on February 6th 2025. The left image is a Knox-Thompson reconstructed from red continuum broadband camera. The right panels are intensity maps reconstructed from spectral observations by the MTR2 spectrograph observing the H_\alpha absorption line. Theses maps are reconstructed from a scan by the telescope of the active region. While these intensity images have a lower spatial resolution, they provide a wealth of spectroscopic information. The region was observed during a flare, as can be noted by the typical ribbon-shape emission in the H_\alpha line centre. This emission is absent from the continuum emission, indicating a chromospheric emission phenomena. Meanwhile, the red wing maps (H_\alpha+1Å and H_\alpha+1Å) display dark absorbing material above the location of the flare ribbons, signature of down-flowing dense material, a phenomena nicknamed "coronal rain".
 </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.
-[[results:gallery:imofmonth|Past images of the month]]
+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.
+[[science:imofmonth|Past images of the month]]