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).

 

 

What goes up, goes down

On 20 August 2026, C8.0 class flare occurred in active region NOAA 14513. The active region was at about Eastern limb of the Sun. The flare was accompanied by a filament eruption, and a coronal mass ejection (CME).  Flare brightennings start appearing at about 11:24 UT.  Full flare ribbon is seen at 11:34 UT, and the first signs of erupting filament appear a minute later  at 11:35 UT.  CCOR1 observations show bright CME front appearing at about 12:00-12:15 UT. Attached video shows the filament eruption as observed by GONG at Teide (Canary Islands) station.

While most of the filament material leaved the Sun and formed the CME, some material can be seen falling down to the Sun. 

 

Some good news from CTIO

Finally we received good news from CTIO. Their TelOps day crew resumed working on Tololo regularly yesterday, although it will be next week before they have staff staying overnight. NISP team is attempting to restart the GONG operations. The skies over Tololo are beautifully blue (photo is courtesy of S. Heathcote).