Solar Activity Report: August 24 - 30, 2026

Solar activity varied from very low to medium levels during the reporting period. Seven M‑class flares were recorded during the first three days, all originating from active region 14513, followed by a gradual decline to low activity. Peak activity occurred between midday August 24 and midday August 26, including the strongest event of the week - an M6.9 flare on August 25. In addition, several medium-to-high intensity flares were produced during this period. From August 27 onward, the Sun remained quiet, producing only a few low‑intensity C‑class flares through August 30.

Far side helioseismic maps reveal several active regions on the far hemisphere. While most exhibit a low likelihood of appearing on the visible disk, an active region (14507 from the previous Carrington rotation) has a moderate probability of rotating onto the front side. Provided it does not decay, it is expected to return to the Earth‑facing hemisphere on September 4.

Challenges in Access to NISP Data

The data server of the NSO Integrated Synoptic Program (NISP), which provides access to GONG and SOLIS data, has been recently impacted by extensive web scraping activity. Subsequent security measures have greatly improved access; however, there are still periods where the scraping activity slows down significantly the access for all users including the operational space weather and the research communities. We are considering changes to the data access via user registration services, but as a temporary solution, the data center has implemented a IP-based priority access list for selected stakeholders. If you experience issues with accessing NISP data, please contact the data center at nispdata@nso.edu.

One day in the life of a large filament

A large chromospheric filament was present in the solar Northern hemisphere for several days. First, it could be spotted on 24 August 2026, as a prominence above the Eastern limb. Full disk image taken by GONG/Learmonth (Australia) shows this filament (circled) at the start of 30 August 2026. Later that day, the filament became active, and it disappeared. Filament eruptions are commonly associated with the coronal mass ejections (CMEs), but the coronal observations from SOHO/LASCO and GOES-19/CCOR-1 do not show an indication of a CME associated with this filament disappearance.  Nor there is an indication of a coronal blast wave in SDO/AIA observations (called Moreton wave, when observed in the chromosphere), which is another signature of a CME. Attached video shows the disappearance of this filament as observed throughout the day by GONG stations in Learmonth (Australia), Teide (Canary Islands), and Cerro Tololo (Chile). Video starts at about 00:00 UT, and it ends at 16:57 UT.  Transition between the instrument/sites is clear from changes in quality of the video. To reduce the size of video, the cadence is reduced from 1 minute to 4 minutes. GONG images can be accessed via the instrument website.

 

 

 

Small filament eruption, but no CME

GONG CT (Chile) station is back on line, and it produces great data! Starting at about 13:15 UT on 22 August, 2026, a small filament in the south-eastern solar hemisphere begun activating. Attached image shows location of the filament by a blue oval as observed by GONG/CT (Chile).  Coronal images from SDO/AIA (right side of the figure) indicate some restructuring taking place in the location of filament. The filament erupted and disappeared from H-alpha images at about 20:38 UT. Coronagraphic images did not show any sign of a CME associated with this filament eruption. There were two small coronal holes located East and South of the eruption site, and their walls might have deflected the filament eruption. Small chromospheric brightennings briefly observed south of the filament after its eruption may indicate the material falling back to the surface. This evolution is shown in the attached video.

Flare, CME and postfare loops

 

 

 

 

 On 21 Aug. 2026 at 9:09 UT, M1.7 class limb flare started above active region 14507. The flare peaked at 9:57 UT. Bright front of a coronal mass ejection (CME) was observed by LASCO C2 coronagraph at 9:36 UT. As the flare developed, a set of postflare loops was formed above the active region. In classical flare model, the postflare loops are formed  in the tail of rising magnetic flux tube which eventually form the CME. Cartoon published by Cheng et al (2011, DOI: 10.1088/2041-8205/732/2/L25) demonstrates this development. As the reconnection site moves higher in the corona, the postflare loops formed higher and higher. GONG stations in Canary Islands and in Chile recorded the development and evolution of postflare loops. First sign of the reconnection can be seen in GONG/TD images starting at about 10:10 UT. Attached video shows the development and evolution of postflare loops as observed by GONG/TD. Second video shows postflare loops in later phases of CME eruption as observed by GONG/CT.

 

 

GONG data processing update

Processing of the network-merged daily velocity and magnetogram images, p-mode-coefficient time series, and ring-diagram analysis products for GONG month 315 covering the period 20260418 to 20260523,  and  the  p-mode frequency data products for central GONG month 314 spanning 20260313 to 20260417 is completed and the data products are now available.

GONG at CTIO is back on line

GONG at Cerro Tololo Inter-American Observatory (CTIO, Chile) is back on the Sun and observing! Below is one of the first H-alpha images taken early today (21 Aug 2026).