Update on GONG/CTIO

GONG at CTIO* continues to be down in aftermath of an exceptionally powerful winter storm system. Here is a brief update from the Observatory:

The Facilities Operations (FacOps) team were finally able to reach the summit of Tololo on Friday (July 24). 

The access road washed out in many places making it passable only for 4x4 vehicles with very experienced drivers. Work is underway to improve the road's condition so that more staff, and importantly, supplies of fuel and water can reach the site. Unfortunately, more bad weather is forecast for next week and over next weekend.

The observatory ran on generator during the storm, but fortunately, commercial electric power was restored yesterday just as we were about to run out of fuel. We now need to restock, which requires using special all-wheel drive fuel tankers. We are concerned that the commercial electric power remains fragile.

The water system on Tololo is also out of service, and we will likely need to transport water to the mountain.

Yesterday, there was only time for quick external inspections, but these suggest there has not been major damage to the telescopes, and other facilities on Tololo.

------ 

*Cerro Tololo Inter-American Observatory (CTIO) is a complex of astronomical telescopes and instruments located approximately 500 km (310 miles) north of Santiago, and 80 km (50 miles) to the east of La Serena, Chile, at an altitude of 2200 meters (7200 feet).

 

 

Status of GONG Network

Currently, only three GONG stations are in operations (GONG/BB - Big Bear, California, GONG/LE - Learmonth, Australia, and GONG/TD - Teide, Canary Islands). 

GONG/UD is down for the monsoon. 

GONG/CT is down in aftermath of severe winter storm.

GONG/ML is down in aftermath of volcanic eruption: Road access to the Mauna Loa Observatory has been restored. However, there is still no commercial power to the site. Hawaiian Electric is working on restoring the damaged power lines. It plans having electric power to the observatory in Fall 2026.

With three sites down, most recent GONG duty cycle (window function) plot shows gaps in coverage. When the weather cooperates, however, even with 3 sites, the network may achieve a duty cycle above 90% as evident from the most recent window function plot.

For a real-time information about GONG stations, see https://monitor.nso.edu/.

GONG AT CTIO

Over the past few days, Chile has been impacted by an exceptionally powerful winter storm system. The storm brought intense rainfall, strong winds, flooding, landslides, and road closures across the Coquimbo Region. Some areas experienced exceptionally heavy rainfall over a very short period of time. 

 GONG station at the Cerro Tololo Inter-American Observatory was shut down prior to the storm. However, returning to operations will unfortunately take a significant time.  The reports indicate that the parts of paved section of the road to the observatory are washed out. The electric power is also out, likely due to downed power poles. The main network fiber is down, but the microwave backup is still working at present, so there is network access, albeit at much reduced speed. For more recent updates, see here.

Image: The public road leading to Cerro Tololo and Cerro Pachón washed out at the San Carlos ravine. Credit: Elquiglobal via Instagram

It's cloud illusions

For astronomical observations, clouds are nuisance as they block star and sunlight and distract the observations. But some (e.g. cirrus) clouds also convey information about changes in weather or the approaching weather storms that astronomers could use for planning of their observations. Some cirrus clouds may exhibit irisation, when a thin clouds is rainbow-colored as in soap bubbles. Here is one example of such clouds from Boulder, Colorado. Cloud iridescence is caused by the diffraction of the sunlight on small water droplets or ice crystals uniformly distributed inside a cloud.  

Cloud iridescence may also be observed in much more rare noctilucent clouds (or polar mesospheric clouds). These clouds are formed at 75-85 km in Earth atmosphere and contain tiny ice crystals, which can scatter sunlight.  These clouds are observed at twilight when the sun is several (5-15) degrees  below the horizon.  Second photo shows example of noctilucent clouds. 

 

Solar Activity Report: July 6 - 12, 2026

 

Solar activity during the past week showed a significant decrease compared with the preceding week.  By Tuesday, the average X‑ray flux level had declined to the B category level, where it remained despite intermittent M‑ and C‑class flares. The strongest event of the week was an impulsive M4.0 flare on July 7 from active region 14482. This region also produced two additional notable flares; M1.5 on July 8 and M1.1 on July 9. Another M‑class event, a long‑duration M1.1 flare, was observed on July 12 from active region 14485. The locations of these two active regions on July 8 are shown in the attached magnetogram. The least active day of the week was July 11, when flaring was limited to C1‑level activity from AR 14485. These flares generated several CMEs, though none had an Earth‑directed component.  

Helioseismic maps of the far side indicate that three active regions, 14478, 14479, and 14480, remain on the back hemisphere of the Sun not visible from Earth. These regions produced elevated level activity while on the front side, including an X‑class flare and multiple M‑class flares, before rotating to the far side around July 5 - 6. They are expected to return to the front side toward the end of this week or early next week, provided they do not decay over the next few days.

Does the Shutdown of a Single Site Affect the GONG Network Duty Cycle?

The duty cycle measures how many observations are available over a given period. For GONG, it generally represents the fraction of observations obtained during a single day. The six GONG sites distributed across the northern and southern hemispheres were selected to ensure that at least two sites observe at any given time, with no interruption to the observations during the non-observing period of one site. Their locations were carefully chosen based on long‑term weather patterns and year‑round sunlight availability. A detailed study of the duty cycle for individual GONG sites and for the full network clearly demonstrates that the network duty cycle is adversely affected by the shutdown of a particular site only when adjacent sites also lack observations.

For example, the Udaipur (UD) site was turned off on July 8 due to the Indian monsoon. The gap in the network observations on this day (marked in the left figure) is not caused solely by the shutdown of UD - it occurred because the adjacent El Teide (TD) site during the overlapping periods with LE and UD on the same day was down due to a technical issue. Once that issue was resolved the following day, the network duty cycle returned to its usual high value and has remained stable. 

The figure below reinforces this point: on July 7 and 9, both TD (green oval) and Learmonth (LE marked by the red oval) provided observations, and no comparable gap appeared in the window function despite UD being offline. The absence of UD observations is indicated by the brown ovals for July 7 - 9, while the brief overlap between LE and TD on July 7 and 9 (shown by the gray shaded bars) ensued continuity to the observations. Provided TD and LE remain operational, no major duty‑cycle impact is expected during the UD monsoon shutdown.

It is important to note, as mentioned previously, that the Mauna Loa (ML) site in Hawaii has been offline since late November 2022 due to a volcanic eruption, and efforts are ongoing to restore operations. There have been periods when the network duty cycle has dipped for the reasons described above, including weather‑related or technical issues. Even when high duty cycle values can be achieved with fewer observing sites, full operation of all six sites remains essential for the precise determination of the p‑angle (the angle that defines the true solar north in the images) which is critical for measuring subsurface flows using helioseismic methods.  Moreover, a network with a reduced number of operational sites is inherently more vulnerable to lower duty cycle performance over the course of the year.

GONG/Udaipur is down for monsoon

The monsoon has arrived in Udaipur, India for the 2026 season. Consequenty, GONG station in Udaipur  (GONG/UD) has initiated its seasonal monsoon shutdown. On July 8, at 14:05 UT, the GONG/UD preventive maintenance (PM) flag was officially set to reflect that the station is in its monsoon season shutdown.

Solar Activity Report: June 29 - July 5, 2026

 Solar activity ranged from moderate to high throughout the reporting period. Multiple C‑ and M‑class flares occurred each day, along with two X‑class flares on separate days. In total, 42 M‑class flares were recorded, majority of them originating from active regions 14475, 14478, 14479, and 14480, which produced 3, 5, 30, and 4 M‑class flares, respectively.

An M1.4 flare from active region 14479 was the strongest event on June 29. Activity reached high levels on June 30 with an X1.1 flare from the same region and an M5.8 flare from active region 14475. A sustained sequence of M‑class flares kept activity high on July 1, most of them from region 14479; its largest event was an M3.5 flare, accompanied by several high‑intensity C‑class flares. Region 14478 also produced an M8.5 flare following C‑class activity.

Activity remained moderate on July 2, with several M‑class flares from regions 14479 and 14480; the strongest was an M4.2 flare from region 14479. Moderate activity continued on July 3 due to flaring from regions 14478 and 14479. Region 14479 produced an M6.7 flare from the northern hemisphere, followed shortly by an M6.3 flare from region 14478 in the southern hemisphere.

Solar activity rose to high levels again on July 4, with more than ten M‑class flares and one X‑class flare. The X1.3 event originated near the southeast limb from active region 14482 as it rotated toward the Earth‑facing side. High activity persisted on July 5, with nine M‑class flares; the largest was an M5.3 flare from region 14479.

Region 14478 was the largest active region during this period. All major flare‑producing regions are now approaching or crossing the west limb, leaving the Earth‑facing side less active. Several CMEs were observed, some producing glancing impacts on Earth.

The latest helioseismic map of the far hemisphere shows several active regions, some of which remain roughly two weeks away from rotating into Earth view, provided their magnetic signatures persist. A moderate‑sized region near the equator in the southern hemisphere is expected to reach the east limb around July 12. Collectively, these regions may contribute to elevated activity on the far side that will be hidden from direct observations.

The IEEE BigData Cup 2026

Segmentation of solar filaments using GONG H-alpha observations was selected by the Institute of Electrical and Electronics Engineers (IEEE) for their (IEEE) Big Data Cup 2026 as one of seven Data Challenges at the Frontier of AI, Science & Society. The challenge is to produce pixel-precise segmentations of solar filaments in full-disk H-Alpha images — capturing fine structures (barbs), separating faint material from ground-based noise, and detecting each filament as one coherent object. Any method is welcome, from classical image processing to deep neural networks.

 

For more information and to enter, see Azim Ahmadzadeh, Dustin J. Kempton, Qin Li, and Alexei A. Pevtsov. Solar Filament Segmentation Challenge 2026. https://kaggle.com/competitions/filament-segmentation-2026, 2026. Kaggle. 

Solar Activity Report: June 22 - 28, 2026

 Solar activity remained at low levels during the past week. The X‑ray flux stayed mostly in the B range from June 22 through midday on June 23, after which it rose to the C level and remained there for the rest of the week. Numerous C‑class flares were produced by multiple active regions throughout the period. The strongest events observed from Monday through Sunday were C1.5, C8.7, C3.8, C6.6, C5.7, a long‑duration double‑peak C7.4, and C9.5, respectively.  The largest active region on the disk was AR 14478 in the southern hemisphere, which, along with AR 14475, also located in the southern hemisphere, was responsible for most of the week’s flaring activity. Multiple CMEs were also observed in coronagraph imagery during this period, a couple of them likely contained Earth‑directed components. The first CME is expected to arrive at Earth between 29 - 30 June, with a second CME around 1 July. No additional Earth‑directed CMEs were identified. 

  Helioseismic maps of the far side show no significant active regions likely to rotate into Earth view in the next few days.  

 

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 314,  and  the  p-mode frequency data products for central GONG month 313 is completed and the data products are now available.

The largest sunspot group of 2026

Sunspot group 14478 observed today (June 28, 2026) East of solar central meridian has a total area of 1190 Millionth of Solar Hemisphere (MSH). This makes it the largest sunspot group of this year. Attached image from GONG Learmonth station in Western Australia shows this group with two large sunspots on the left side of the solar disk. While this is a large sunspot group, it is not a record-breaking one. The largest sunspot group was observed in April 1947. The sunspot drawing from the Mount Wilson Observatory in California provides example of that monstrous sunspot group on 7 April 1947. The drawing is scaled to match the size of GONG image (circle corresponds to the same disk size as GONG). The area of that group was 7400 MSH, or about 6.2 times of AR14478. Sunspot group areas approximately scale as the total magnetic flux of an active region. Groups with larger areas have more potential for producing solar flares and coronal mass ejections. In comparison, in March 1989, an active region with the total area of 2400 MSH produced a very powerful flare and CME. The eruption caused one of the strongest geomagnetic storms, which resulted in a nine-hour outage of Hydro-Québec's electric transmission system in Canada. The Carrington event (1-2 September 1859) was associated with an active region of 2300 MSH in size. However, not all large sunspot groups produce strong eruptions. So far, AR14478 showed only a few moderate C-class flares.

Solar Activity Report: June 15 - 21, 2026

 Solar activity during the past week generally remained at low levels, except for the final two days when several M‑class flares were produced. Only low‑intensity C‑class flares were observed through June 19, after which activity increased with the arrival of active region 14473. The strongest event of the week was an isolated M6.8 flare on June 21 from AR 14473. This region also generated two additional moderate flares, an M1.0 on June 20 and an M2.6 on June 21. Active region 14472 produced another moderate flare, an M1.3, on June 20. June 16 was the least active day of the period, with X‑ray flux remaining mostly below the C level. Several coronal mass ejections were reported, though none had an Earth‑directed component.

Helioseismic mapping of the farside indicates a moderate‑sized active region in the southern hemisphere that may rotate into Earth view around June 24.

GONG weekly movies of solar activity

GONG is now producing weekly summaries of solar activity. The videos are created on a daily basis, but each movie covers about one full week of time. Attached image provies example of video created today (22 June 2026). It shows H-alpha images with and without prominences (upper panel), light-of-sight magnetogram (low-left) and a broadband image (low-right). The video may include observations with clouds and other artefacts. The videos can be accessed via https://gong2.nso.edu/products/dailyMovies/

Solar Activity Report: June 8 - 14, 2026

 Solar activity during the reporting period remained at low levels, with only C‑class flares observed. The strongest event was an impulsive C9.0 flare from active region 14465 on June 11. Additional C‑class activity from the same region included C7.2 and C4.5 flares on June 8, a C4.5 flare on June 9, a long‑duration C6.7 flare on June 11, and a C5.2 flare on June 12. Several low‑intensity C‑class flares were also produced by multiple active regions. As a result, active region 14465 was the most flare‑productive region of the period. A few CMEs were observed, but none contained a significant Earth‑directed component.

The latest helioseismic mapping of the Sun’s far hemisphere indicates that a strong active region in the southern hemisphere may rotate into Earth view around June 20 - 21, provided it maintain or increase the strength over the next few days. At present, the region exhibits helioseismic signatures consistent with strong far‑side activity.

Update on recent conferences

This year, the American Geophysical Union (AGU) and Japan Geoscience Union (JpGU) organized a joint JpGU-AGU meeting in Tokyo, Japan. A special full-day session on "Frontiers in solar physics: observation, modeling, and long-term research from the past to the future" was organized by NSO personnel. Presentations for this session included breakthrough results from several missions (SDO, Hinode, Proba-3, Aditya-L1, Sunrise) and groundbased observatories including DKIST and Goode Solar Telescope, AI/ML, and numerical modeling.

June 10-11, 2026, NASA’s Extreme Precision Radial Velocity Research Coordination Network (EPRV RCN) group has organized on-line workshop to explore potential synergies in data/facilities/analysis methods between the EPRV and the solar physics communities with a focus on understanding the solar phenomena that cause spectral line-shape deformations and spurious RV signals. See the event web page at: https://eprv-rcn.github.io/events/eprv-solar-workshop/. Serena Criscuoli gave invited presentation on "Overview of DKIST" and Alexei Pevtsov reported on "Next generation Ground based solar Observing Network (ngGONG)".

NSO was represented at the Space Climate 10 Symposium by two oral presentations, one poster, and as co-authors in one invited talk (https://indico.global/event/17578/contributions/). GONG and SOLIS data were mentioned by several presenters. Attached image shows presentation by Dr. Theodosios Chatzistergos, who used GONG (broadband/white light) data for reconstructing the total solar irradiance.

Update on GONG window function

The Quick-Reduced duty-cycle plots(see previous post) are now being automatically generated in production, and the simple public-facing webpage allowing users to get these plots is now live and will automatically update as data from new months becomes available. The new page has replaced the old page, so you can access the plots from https://gong.nso.edu/data/merged/gong+_merged_plots.html. This can be found from the GONG Data Archive page by navigating to the "Reference | Documentation" link at the top of the page and clicking on the "GONG Network Merged Image Window Function / Duty Cycle (graphical)" link near the top. The old (now archived) set of plots from 2002-2010 is still available from the new page. The team is working on additional window function plots to represent the contribution of individual stations.

GONG Farside Helioseismic Mapping Project: Release of Upgraded Data Products

 NISP has released an upgraded version of the data products generated by the improved farside helioseismic mapping pipeline (GONG Farside Maps), which utilizes full disk GONG Dopplergrams This upgradation incorporates substantial improvement to the pipeline, addressing long standing issues and implementing new strategies throughout the workflow. Several new data products are now available to better serve the broader community.

Data products from the previous pipeline (hereafter the Legacy pipeline) will continue to be produced through the end of this calendar year to support direct comparison. All products are accessible through the link above as well as on the GONG data download page.

The figure below compares the seismic signatures of magnetic activity on the far side of the Sun as computed using the Legacy pipeline (top panel) and the upgraded pipeline (bottom panel). In the Legacy pipeline, regions of strong magnetic field appear as dark areas. In contrast, the upgraded pipeline provides more detailed information: the farside maps are shown with a dark background, high magnetic field regions appear as bright features, and the frontside magnetograms are displayed in grayscale. The identified farside active regions and their probabilities of appearing on the East limb are marked by circles in both versions of the pipeline.

A strong active region may rotate into Earth view on June 12–13, 2026

 

Helioseismic mapping of the Sun’s far (invisible) hemisphere indicates the presence of a strong active region that may rotate into Earth view around late June 12. This active region is marked by a circle with 100% probability. The figure below shows its Carrington‑longitude location, highlighted by the yellow dashed line in three maps separated by seven days: June 10 (top), June 3 (middle) and May 27 (bottom).  The dark portions of each map represent the far hemisphere, while the grayscale corresponds to the front side. The bright features on the far side mark active regions that cannot be observed directly from Earth.

A careful analysis shows that the active region of interest was either in a very early stage of development when this portion of the Sun was on the front side, or it had not yet evolved. It is not clearly visible in the bottom map. Although there was an active region at a similar longitude, its latitude differs by about 10 degrees. The middle map shows only a weak farside signature, but the region becomes clearly visible in the top map, with strong helioseismic signals and a 100% probability of appearing on the front side. The maps from June 3 to June 10 indicate that the region has evolved over time and strengthened significantly in the past couple of days. Strong active regions of this kind tend to enhance magnetic activity and may trigger severe space‑weather events. 

It is worth noting that several other active regions have rotated to the farside and are currently progressing through their farside transit.  

Solar Activity Report: June 1 - 7, 2026

Solar activity fluctuated from low to high and then returned to low levels during the reporting period. The quietest day was June 1, marked by isolated low‑intensity C‑class flares; the strongest event that day was a C1.5 flare from active region 14449 in the southwest portion of the solar disk. Activity increased to moderate levels with frequent C‑class flares and three M‑class events: M3.3 and M1.3 flares from active region 14455 in the northern hemisphere, and an M1.2 flare from active region 14461 near the southeast limb.

Activity rose further on June 3, reaching high levels when active region 14455 produced three major flares - M9.3, M7.7, and the week’s strongest event, an X1.0 flare. Following this peak, activity declined, with the strongest events being a C2.6 flare on June 4 and a C4.7 flare on June 5. Activity briefly returned to moderate levels on June 6 with an M1.8 flare from active region 14461. By June 7, conditions had settled back to low levels with only low‑intensity C‑class flares.

Several of the M‑ and X‑class flares were associated with coronal mass ejections (CMEs) that produced minor to moderate geomagnetic activity.

GONG/CT - Site Update

 The CT GONG shelter painting project was completed this week. The project included repairs and painting of the roof and perimeter fence. Many thanks to the NSF NOIRLab staff at CTIO for getting the project finished before the snowfall starts. 

Photos: Esteban Parkes / NSF NOIRLab CTIO

Large solar flares and CME eruption

On 3 June 2026, Active region 14455 produced several major (M- and X-class) flares and eruptions. Attached video shows solar activity during this period as observed by GONG/El Teide (Canary Islands). A major flare of M7.7 class peaked at about 7:00 UT and another flare of X1.0 class peaked at about 11:28 UT. Flares of this class are typically associated with the coronal mass ejections (CMEs) and in fact, there is an idication of the erupting material during the first flare (see dark filamentary structures appearing shortly after the flare brightenning). LASCO C3 coronagraph shows CME signatures for both events.

NSO/Kitt Peak Fourier Transform Spectrometer

 

https://noirlab.edu/public/images/noao-sun/

The Fourier Transform Spectrometer  (FTS) was operating at NSO's McMath-Pierce Solar Telescope from early 1970 (1971-1976) till 2001. In 2012, it was relocated to Old Dominion University in Norfolk, VA. The FTS data were used for solar and atmospheric physics research, and to develop several high-spectral resolution atlases of solar spectra: Flux from 296 to 1300 nm; Photosphere from 357 to 740.5 nm; Photosphere from 735 to 1123 nm; Infrared from 1100 to 5400 nm; Sunspot from 8100 to 21,000 nm plus photosphere from 16,000 to 22,000 nm; Sunspot umbra from 664.2 to 1123 nm; Sunspot umbra from 1160 to 5100 nm.

Recently, Mr. John Williams developed an interface for displaying solar spectra and extracting data from different FTS atlases. The interface can be accessed via fts.terrazoom.com.

Solar Activity Report: May 25 - 31, 2026

 

During the past week, solar activity was predominantly low, characterized by low‑intensity C‑class flares. The most significant event was an M1.1 flare on 29 May originating from Active Region 14455 in the northeast quadrant. All remaining activity consisted of low C‑class flares, and no Earth‑directed CMEs were identified.

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 313,  and  the  p-mode frequency data products for central GONG month 312 is completed and the data products are now available.

Solar Activity Report: May 18 - 24, 2026

 Solar activity at the beginning of the week was at low levels, with the X‑ray flux holding in the B range except for a few low‑intensity C‑class flares. Activity dipped even further on 20 May, when the flux remained entirely below the B–C threshold. By mid‑day on 21 May, conditions shifted. Activity rose following three short‑duration, high‑intensity impulsive C‑class flares from Active Region 14436 as it approached the northwest limb: C5.6, C8.3, and C9.5. A more substantial increase occurred on 22 May, when an M2.3 flare erupted from just beyond the northwest limb, near the same active region, pushing activity into the moderate range. On 23 May, a series of low and medium intensity C‑class flares were recorded and the week concluded with low flaring activity. Most of the flaring during the last two days originated from newly emerged Active Region 14446 near the southeast limb. Multiple CMEs were observed in coronagraph imagery, but none were Earth‑directed.

Helioseismic map of the far hemisphere (see the attached pictures) reveals two strong active regions, marked by while circles, forecast to return to Earth view on 27 and 31 May.  A third region, marked by a red circle, shows a detectable helioseismic signature, but its probability of appearance remains below our confidence threshold. If it continues to strengthen, it should reach the east limb on 29 May. The far‑side active region mentioned in last week’s report has now rotated onto the front side and has been assigned NOAA 14446.

Small flare near solar central meridian

 Not all solar flares are large. This example shows a relatively weak flare (X-ray C1.3 class), which erupted from active region 14439 on 22 May 2026. The flare started at about 4:38 UT and peaked at 4:50 UT.  C-class flares are typically not associated with the Coronal Mass Ejections (CMEs). GONG at Learmonth, Australia captured the flare with its H-alpha instrument, as shown in this short video (4:20 UT - 7:12 UT)

 

GONG Network Window Function

Last week, NISP Data Center has been working on re-instating the GONG network window function monthly plots that were generated and discontinued a few years ago. Once completed, the window function plots would be available at https://gong.nso.edu/data/merged/gong+_merged_plots.html. Example of old-format window function for the month of April, 2026 is shown below. For each day of the month, red-colored bars represent periods with network observations. Gaps shown in the white color are periods without observations. The impact of missing observations from GONG at Mauna Loa observatory is clearly visible as larger data gaps in late (20-24 UT)  and early (0-4 UT) periods of the day. Numbers of the right side of the plot show average daily duty cycle (% of 24 hour period with observations). Even with one station down, the network still meets the required duty cycle. 

Solar Activity Report: May 11 - 17, 2026

 Solar activity during the reporting period remained mostly at low levels, rising to moderate levels at the end of the week when several low‑intensity M‑class flares were produced. The X‑ray flux generally stayed in the B range, with only a few low‑level C‑class flares until May 13. Activity then increased gradually, with medium‑ to high‑intensity C‑class flares, followed by four M‑class flares on May 16 and 17. The strongest events were two M1.9 flares on May 16. The remaining M‑class flares were an M1.3 on May 16 and an M1.7 on May 17. These events originated from active regions 14435 and 14436, with AR 14436 also producing a C9.7 flare on May 17. No Earth‑directed CMEs were detected during this period.

The latest helioseismic map of the Sun’s far side (see attached image) shows a large active region in the southern hemisphere that has continued to strengthen since it first appeared. It is visible in the image as a prominent bright spot. It is expected to rotate onto the East limb late on May 23. This substantial region has also been observed by ESA’s Solar Orbiter and NASA’s Perseverance rover, both of which currently have partial views of the Sun’s far hemisphere. Solar Orbiter has already detected a couple of X‑class flares and nearly a dozen M‑class flares over the past three days. If the region maintains its magnetic structure and continues to intensify, solar activity levels are likely to increase toward the end of the week.

Solar M5.8 class flare as observed by GONG

 Video: Niles Oien, NSO

 A major solar flare of X-ray class M5.8 erupted on May 10, 2026 from active region 14436 near the solar East limb (N19E65). M- and X-class flares are some of the most energetic solar events, typically associated with the coronal mass ejections (CMEs). However, CMEs originating near solar East limb are less likely to impact the Earth.  Attached video shows the development of this flare as observed by GONG H-alpha at Cerro Tololo, Chile.

  

A Recent Visitor to the Boulder GONG Farm

When a cloud is not a cloud! Roosting birds like this visiting hawk can cause a false cloud indication in the site's pyranometer data (see large dip in intensity plot on the right). Pyranometer is a device to measure the amount of sunlight at each site from the sunrise (left side of the plot), noon (peak), and sunset (right side of the plot). Clouds appear as dips in this otherwise a smooth plot. Colloquially, GONG engineering site (in Boulder, Colorado) is often referred to as "GONG farm". This originates in early period of GONG development, when the test site was set up on the grounds on the Agricultural Experiment Station of the University of Arizona in Tucson.

  

Photo: Detrick Branston / NSO

GONG/CT - Site Update

The shelter painting project at CTIO has commenced. Brief data outages are anticipated this week as the the painting crew works above and around the light feed turret.

Photo: Esteban Parkes / NOIRLab CTIO

 

GONG Project Presence at the 2026 Space Weather Workshop

The GONG Project presented a series of four coordinated posters at the recent 2026 Space Weather Workshop in Boulder, CO. The series of posters was introduced by an overall GONG Project Overview, followed by three supporting posters highlighting GONG Science, GONG Data, and GONG Operations.

A number of NISP staff members attended the workshop to present the posters. Workshop attendees were very receptive of this comprehensive presentation, and a number of  interesting conversations were had.

• "GONG: A Global Ground-Based Network for Continuous Solar Observations" by A. Pevtsov et al.
• "The Continuing Role of Scientists in Sustaining the GONG Project" by S. Tripathy et al.
• "GONG Solar Data Collection, Processing, and Distribution" by O. Burtseva et al.
• "GONG Operations and Engineering Support" by G. Card et al.

GONG/ML Site Update

Site Access:

The Mauna Loa Observatory remains closed to the general public. Since the site will be an active construction zone for the next two years, NOAA staff are tightly scheduling site access for mission-critical activities only to ensure personnel safety. All visitors require explicit authorization to access the site.

Site Power and Construction Update:

NOAA does not have a date for commercial power restoration, but is actively engaging with local utility provider, HELCO. Concurent to HELCO repairing power lines and poles, site power and network infrastructure upgrades will be occuring at MLO.  GML will provide updated timelines for restoring power back to campus buildings when an updated construction schedule is available - full power restoration is likely several months after HELCO repairs the grid.

The components for the new 40m high sampling tower arrived onsite at MLO. GML will be reaching out to partners impacted by the tower replacement, and will provide a timeline for the installation when available.

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 312,  and  the  p-mode frequency data products for central GONG month 311 is completed and the data products are now available.

Solar Activity Report: April 27 - May 3, 2026

Solar activity during the reporting week remained generally low, with X‑ray flux staying within the low C‑class range aside from a few high‑C and low M‑class events. Activity briefly rose to moderate levels on the first two days: an M1.0 flare from active region 11425 on April 27, followed by three low M‑class flares and several high C‑class flares, including C8.1, C9.0, and C9.3, from the active region 11420 on April 28. Consequently, April 28 was the most active day of the week, and the strongest event was an M1.5 flare from active region 11420. This region also produced a C7.4 flare on May 1 and a C8.7 flare on May 2. No significant Earth‑directed CMEs were detected in coronagraph observations.

The latest helioseismic far‑side map suggests that a moderate to strong active region may rotate onto the north‑east limb around May 9.

Poster presentations by NISP personnel at the 2026 Space Weather meeting in Boulder, CO.

The 2026 Space Weather meeting took place in Boulder, Colorado on 28 April- 1 May, 2026. NISP personnel presented several posters during this meeting relevant to Space Weather research and operational forecast. The presentations included: 

• "VSO 2.0 and Space Weather" by N. Oien et al
• "Full-disk Hα Spectroheliograph development for GONG: Preliminary results" by S. Gosain et al.
• "Limb-Flare Prediction (and...beyond-limb flare prediction) with a 4π Full-Heliosphere Forecasting Framework" by K.D. Leka et al.
• "Polarity-Resolved Magnetograms Derived from GONG Far-Side Helioseismic Maps for Space Weather Applications" by Hamada, A. et al.

More poster references will be added later. 

Solar Activity Report: April 20 -26, 2026

Solar activity ranged from very low to high levels during the reporting period. Activity was very low at the start of the week, with X‑ray flux in the mid‑B-class range, before increasing to the upper B‑class level accompanied by frequent low‑ to mid‑C‑class flares. By early April 23, activity rose sharply, producing four M‑class flares that day. Activity intensified further on April 24 with two X‑class flares (X2.5 and X2.4) and two additional M‑class flares. Finally, the solar activity subsided on April 25 and continued with the similar conditions on April 26, although the X‑ray flux remained in the C‑class range with a few M‑class events. These flares were associated with CMEs, however, none of which had Earth‑directed components.

GONG UD is back on-line

 GONG station in Udaipur, India is back to operations.  NISP team worked with the site support group in India to run series of tests, which identified a failed electronic board. The board was replaced by a spare, and the system's operability was restored. The images error was cleared, and the PM (preventive maintenance) flag is turned off.  H-alpha image of the Sun taken after the repairs is shown below.

 

Solar Activity Report: April 13 - 19, 2026

Solar activity remained at low levels during the reporting period. X‑ray flux was predominantly within the B‑class range, with only occasional short‑lived increases into the C‑class. Active region 14419 was the dominant contributor, responsible for five of the seven C‑class flares recorded, including the strongest event of the week, a C4.1 flare on April 17. Additional low‑level C‑class flares were observed on April 13, 16, 17, and 18, while the remainder of the week stayed within the B‑class range. A few CMEs were detected, none with Earth‑directed components.

GONG network status

As of 18 April: 

• The Learmonth instrument is operational, and the sky is clear. 
• The Udaipur instrument is operational, and the sky is clear. On April 19, the Camera Rotator stopped rotating. Local support team was requested to check if the Camera Rotator amplifier may have a blown fuse. The observations are taken, but the image orientation is not correct (see images below taken on 18 and 19 April). UPDATE: on 20 April, GONG/UD was put into PM mode (no observations are taken) while the team is resolving the issues with oscillations in the camera rotator and the turret. 
• In early April, the internet connectivity at Udaipur experienced some instability. This was traced to a piece of cable chewed by the panther. This piece of cable was now replaced.
• The El Teide instrument is operational, and the sky is mostly cloudy.
• The Cerro Tololo instrument is operational, and the sky is clear.
• The Big Bear instrument is operational, and the sky is partly cloudy.
• The Mauna Loa instrument is down.
• Two engineering sites in Boulder, Colorado (TC and TE) are down for testing.
  
  
   

Solar Activity Report: April 6 - 12, 2026

 Solar activity fluctuated from low to moderate and back to low levels during the week. Most flares were in the C‑class X‑ray range. The week began with only low‑level C‑class activity, followed by an increase to a C5.7 flare on April 7, a C8.9 flare on April 8, and an M1.0 flare on April 9. Activity then dropped sharply on April 10, with only B‑class X‑ray levels observed, and a single C1.9 flare on April 11. Conditions rose slightly on the final day of the week, producing several low C‑class flares, the strongest of which was C2.4. Overall, active region 14409 was the most productive region, generating 11 C‑class flares and one impulsive M‑class flare. No earth-directed CMEs were detected during this period.

Yuri's Night and the International Day of Human Space Flight

Today is the 65th anniversary of first human space flight. On April 12, 1961, Soviet cosmonaut Yuri Gagarin orbited the Earth in the Vostok-1 spacecraft. Coincidentally, the first Space Shuttle mission was also launched on April 12, but in 1981, 20 years after the Gagarin's flight.

Space weather posed issues from the beginning of human space exploration resulting in failure of communication satellites due to radiation damage and electric discharges and loss of satellites due to enhanced atmospheric drag  (DOI: 10.1080/29979676.2024.2391688). GONG network provides critical observations for the operational space weather forecast issued by the NOAA's Space Weather Prediction Center (SWPC) and the prediction centers in other countries. 

Image shows a series of postage stamps issued in 2011 by the United Nations to commemorate 50 years of manned spaceflight. From left to right are the stamp depicting Yuri Gagarin's launch, an American astronaut on a ladder descending to the Moon's surface, the International Space Station, the Space Shuttle, and Soviet Soyuz spacecraft on its way to docking in orbit with the American Apollo spacecraft.

In 2011, the United Nations General Assembly designated April 12 as the International Day of Human flight. Yuri's Night is celebrated internationally since 2001.

GONG/LE is back on-line

Internet connection to GONG station at Learmonth, Australia was restored, and the observations taken on previous days are now flowing to NISP data center. Attached images show example of magnetograms taken on 7-10 April 2026. Status of GONG network can be checked at the Network Monitor site and the data could be accessed via the main NISP data website.

 

Three Decades of Global Oscillation Network Group (GONG): From Helioseismology to Magnetic Field and Space Weather (Invited Review)

A review article on GONG has been published in Solar Physics. It offers a rich historical perspective on the network’s three‑decade evolution, tracing its origins as a three‑year program focused on full‑disk helioseismic Doppler measurements to its current role as a major data source for space‑weather prediction. The article also outlines a forward‑looking discussion on the next major chapter: highlighting plans for the next‑generation network, ngGONG.  

This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits free access while restricting commercial use and modifications.

DOI: 10.1007/s11207-026-02639-9

GONG/ML Status

The temporary Mauna Loa Access Road was officially completed on March 26th. 

While the road is officially open, the official status of the Mauna Loa Observatory remains closed to the general public. Since the site will be an active construction zone for the next two years, NOAA staff will tightly schedule site access for mission-critical activities only to ensure personnel safety. All visitors require explicit authorization to access the site.

Regarding utilities, NOAA does not have a date for commercial power restoration, but is actively engaging with the local utility provider.

Contractors are now on site at MLO installing off-grid solar electric systems for NOAA and MLSO.

Photo: Ben Berkey, HAO/MLSO

 

GONG/LE Status

 Power has been restored to the GONG shelter, and observations are being taken. The GONG engineering & operations staff have been in contact with LSO staff, and are getting regular updates.

GONG Tool screenshot via WhatsApp (Detrick Branston & Brian Newcomb, 4/8/26).

 

 One of the two air conditioning units was damaged beyond repair. All of the control electronics soaked in water, fan cover and fan blades missing. A quote has been received for that work, and the replacement unit has been ordered.

A quote for the replacement of the shelter power disconnect enclosure and surge arrestor is pending. 

Email update 4/9/26: "Electricians have been at the observatory all this afternoon and most days this week testing and replacing water-affected electrical infrastructure in the RSTN (radio telescope) building through which all our comms passes. Once they clear that building for electrical power restoration, we can then turn our attention to the comms side. In addition to this issue (water through the RSTN building), we still have no fibre connection to the outside world. We are working with the BOM IT Support and the internet provider to try to diagnose and resolve this. It is possible that the fibre was damaged at the main road end, as a deep ditch was scoured out by the sea water and rain inundation (we couldn't even drive into the site). "

GONG data are stored on site. The workstation can retain up to 61 days of data. 

Solar Activity Report: March 30 - April 5, 2026

 Solar activity fluctuated sharply over the past week. The period opened at high levels on March 30 with a long‑duration X1.4 flare from active region 14405, located in the southeastern quadrant of the visible disk. Activity then dropped markedly on March 31, with the strongest event reaching only C1.5 before declining into the B‑class range. Conditions rose again on April 1 as multiple high‑intensity C‑class flares were recorded, the largest being a C8.1 event. From April 2 through April 4, activity remained at moderate to high levels, driven by several M‑class and numerous strong C‑class flares. The largest daily events were M3.5, M1.3, and M7.5 on April 2, 3, and 4, respectively. Activity decreased once more on April 5, with a C3.8 flare as the day’s peak.

In summary, April 4 stood out as the most active day of the week. Active region 14409 dominated the activity, producing six M‑class flares and roughly 50 C‑class flares. Several CMEs were detected by coronagraphs throughout the week, but none were assessed to have significant Earth‑directed impacts.

Helioseismic maps of the far side show several active regions currently present. One of them—an active region from the previous rotation—appears to have a high likelihood of returning to the visible hemisphere around April 11.

Major M1.0 X-class flare on April 4, 2026

 On April 4, 2026, a major X-class solar flare of M1.0 magnitude was observed at about 22:54 UT in active region NOAA 14409. The flare was recorded by GONG/Big Bear station using its Hydrogen H-alpha instrument. GONG/BB restarted its observations on the day of flare after been down for a preventive maintenance. Image shows the location of flaring region before (22:39 UT) and during the flare (23:02 UT, marked by thick black arrow). The active region continues exhibiting a complex magnetic configuration and new flux emergence, and thus, may produce additional flares. The observations can be access via GONG website.

 

GONG low duty cycle (updated on 4/4/2026)

GONG network is operating at a very low duty cycle (see plot attached) due to three adjacent stations  down: GONG/Mauna Loa - in aftermath of volcanic eruption, GONG/Big Bear - preventive maintenance trip, and GONG/Learmonth - damages in aftermath of the tropical cyclone (TC) Narelle.

The LE GONG station was shut down on March 25th in anticipation of the arrival of Tropical Cyclone Narelle. TC Narelle caused significant damage to Exmouth and Learmonth, but there is no damage to GONG/Learmonth station itself, except for one air-conditioning units, and some external access power panels. After the electrician inspection, the power to GONG was restored, and the instrument may have resumed observations. However, there is no internet access and thus, data are stored on the site. 

NISP engineering team are performing preventive maintenance work at GONG/Big Bear. It is expected that GONG/BB will be back to operations on 4/4/2026. UPDATED on 4/4/2026: The preventive maintenance was completed. GONG/Big Bear is back to full operations.

Primitive access road to Mauna Loa is completed, but access is still limited. NISP team plans visiting the site for the evaluation of restart activities after the commercial power to the site is restored.

GONG/LE Status

 The LE GONG station was shut down on March 25th in anticipation of the arrival of Tropical Cyclone Narelle. TC Narelle made landfall near Exmouth at approximately 8am on March 27th at a Category 4 level with wind speeds between 160–199 km/h. An electrician was able to visit the site, and power was restored to the shelter on April 2nd. We are awaiting word as to when the internet connection to the LSO will be restored.

 One of the first reports from the LSO staff reads:

"Unfortunately, the damage to Exmouth and Learmonth is significant. The road was closed for days due to flooding and the airport across the road is closed for the foreseeable future due to extensive damage to the terminal.

We were able to access the site for the first time yesterday (March 31st) and inspected the GONG shelter. The shelter and turret appear to be unscathed (no obvious wind damage or impacts) but one of the air-conditioner compressor units has been damaged.

The inside of the shelter was dry (hooray) so we attempted to repower, however the main circuit breaker tripped on both attempts. The metal box surrounding the main circuit board outside was blown open and bent at the hinge, and we suspect water may have gotten in behind it. It's also possible there is water in the light fixtures that may be tripping the circuit breakers.

We are also experiencing a site-wide internet outage, so no data flow is possible currently anyway. We are investigating with the network provider to find out what kind of infrastructure damage has occurred and ETA for return to service. We will keep you posted on this front too."

 

Does the Solar Tachocline Change with Solar Cycle

 A thin transition layer where the Sun’s rotation changes abruptly — the outer convection zone rotates differentially, while the inner radiative zone rotates almost like a solid body- is termed as the tachocline similar to the thermocline in oceanic dynamics.  This sharp shear is believed to generate the Sun’s strongest toroidal magnetic fields, which later rise to the surface as sunspots. The tachocline’s  sub-adiabatic stratification allows strong magnetic fields to be stored without immediately rising due to buoyancy. If the solar dynamo exists in the tachocline and generates the magnetic field of the Sun, one would expect solar-cycle related changes in the properties of the tachocline. 

A recent study using three decades of GONG observations reports a secular shift in the tachocline’s position at low latitudes. The analysis also indicates that the tachocline  has been gradually moving closer to the base of the convection zone, indicating that it may be related to the complexity of the solar magnetic field.  

This work is published in Astrophysical journal, 1000, 272 (1000) 2026 April 1. 

Latitude-dependent Time Variations of the Solar Tachocline - IOPscience

Artemis 2 launch and space weather

Artemis II is scheduled to launch tomorrow (April 1, 2026) on a 10-day mission around the Moon. Traveling outside the Earth magnetosphere may pose additional risks from the space weather events (for review of early studies see Chen et al 2024). NOAA Space Weather Prediction Center will provide forecast of space weather conditions for the duration of mission (see article in Space.com), and the NSF's GONG observations will contribute to the modeling. In addition, recent GONG farside images suggest a relatively low level of sunspot activity on a farside of the Sun for the incoming two weeks. 

Solar Activity Report: March 23 -29, 2026

Solar activity during the reporting period ranged from low to moderate levels. The week began with low solar activity and a C3.2 flare was the largest event on March 23 that originated from active region 14392 near the southeast limb. The X‑ray flux generally remained at B‑level until a C7.3 flare was produced on March 24 by an active region rotating onto the Earth‑facing side from behind the northeast limb. This region was later designated NOAA 14403. Following this event, the X‑ray flux stayed within the C‑level range, with several C‑class flares and two M‑class flares. The largest event on March 25 was a C3.7 flare. Activity increased to moderate levels on March 26 with an M3.9 flare from active region 14403 and multiple additional C‑class flares.

On March 27, activity declined again to low levels, with only C‑class flares observed; the largest was a C5.4 event. Activity increased once more on March 28 with a long‑duration M1.3 flare from active region 14405. The week concluded with low activity on March 29, when the largest event was a C2.1 flare. Overall, active region 14405 was the most productive during this period, generating nine C‑class flares and one M‑class flare. Several CMEs were associated with these events, but none had Earth‑directed components.

Status of GONG network: March 27, 2026

 Status of GONG network as of Friday, March 27:

• The Learmonth instrument is down due to passage of a tropical cyclone (see map below showing path of tropical cyclone Narelle 34U, © Bureau of Meteorology) 
• The Udaipur instrument is unreachable (local team was requested to investigate).
• The El Teide instrument is operational, and the sky is clear.
• The Cerro Tololo instrument is operational, and the sky is clear.
• The Big Bear instrument is down for scheduled maintenance. NISP engineering team is on site performing preventive maintenance.
• Road to Mauna Loa Observatory is officially completed. However, it remains closed for general public and non-emergency observatory access.

Solar Activity Report: March 16 - 22, 2026

The week began with moderate solar activity, which declined to low levels by mid‑week and remained low for the rest of the period, with only a slight gradual increase in X‑ray flux intensity that stayed within the B‑class range. Three low‑intensity M‑class flares occurred at the start of the week, one on each of the first three days. The most active day was March 18, when an M2.7 flare was produced, along with C2.7, C2.8, C2.9, and C3.6 flares. Other notable flares include an M2.8 and C5.9 on March 16, an M1.3 on March 17, and a C2.3 on March 19. All of these flares originated in the southern hemisphere, primarily from active region 14392. Two associated CMEs from the March 16 and March 18 M‑class flares arrived simultaneously on March 20.

Helioseismic mapping of the invisible hemisphere indicates that several active regions may rotate onto the Earth‑facing side within the next seven days. One of them is active region 14378, which crossed the west limb and moved to the far side about two weeks ago, has persisted and is expected to reappear at the east limb around March 24. 

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 311,  and  the  p-mode frequency data products for central GONG month 310 is completed and the data products are now available.

GONG refurbishment project update

NISP Data Center, scientists, and engineers have successfully completed vetting the last twelfth GONG EVT camera.