Solar Activity Report: October 19 - 25, 2026

 Solar activity continued to decline as the current solar cycle progressed through its declining phase. Activity levels remained low throughout most of the reporting period, with the exception of October 19, when Active Region 14551, located in the southwestern quadrant of the solar disk, produced an M1.6 flare, temporarily elevating activity to moderate levels. This was the strongest event recorded during the week. Several low-intensity C-class flares were also observed throughout the reporting period. By the end of the week, nearly all numbered active regions had rotated onto the far side of the Sun, leaving the Earth-facing disk largely devoid of significant activity.  The attached figure displays three sample images obtained at the Big Bear GONG site on October 25, toward the end of the reporting week. No Earth-directed coronal mass ejections (CMEs) were detected during this period.

Analysis of recent far-side helioseismic maps suggests the emergence of a new moderate-sized active region in the northern hemisphere. Based on its current location, the region is expected to rotate onto the visible solar disk around October 30.

GONG observations for scientific research, operational space weather forecast, and public use

In 1995, GONG started its operations as a 3-year project aimed at investigating the internal structure and dynamical behavior of the Sun through the analysis of solar oscillations (so called, helioseismology). Over the years, GONG observations were used by several generations of scientists to study the parameters of the acoustic modes, and their variations over time and space. Accurate knowledge of variability of these parameters within the solar interior is essential for understanding the origins of magnetic activity and for constraining solar dynamo models. One of the early results of helioseismology using GONG data was the determination of the internal profile of the solar rotation rate as a function of depth. In particular, the sharp transition from differential to solid-body rotation, termed the tachocline, was discovered at the base of the convection zone (about 200,000 km below solar visible surface). Later, a thin shear layer in the rotation rate immediately below the solar surface was detected. The latter is referred to as the Near-Surface Shear Layer (NSSL), or leptocline.

While the line-of-sight (LOS) magnetograms were produced by GONG from the beginning of the project, it was not until 2001, when the magnetograms from the upgraded GONG++ saw the extensive use for studying magnetic properties of the Sun, their changes with the flare activity, solar cycle, modeling of coronal and interplanetary magnetic field, and solar wind.  In 2010, GONG was also upgraded to take observations in hydrogen H-alpha spectral line. 

GONG data continue to be extensively used by the research communities both in U.S. and abroad. See this post for highlights of scientific discoveries and early GONG history.  The data are now used operationally by the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC), the space weather prediction center of U.K. MetOffice, and in other countries (e.g. Japan, South Korea).  For space weather awareness, GONG data are included in the analyses of NASA’s Moon-to-Mars office. GONG observations are downloaded for modeling of solar wind and solar eruptive events by the US university groups, research organizations in Europe, and Community Coordinated Modeling Center (CCMC) operated by NASA. Data is used for predicting the magnetic connectivity between the solar surface and NASA’s Parker Solar Probe (PSP) during its closest (perihelia) approach to the Sun. Farside images derived from GONG data are used for predicting future sunspot activity on Earth, and the appearance of sunspots on farside when observed from the EU's Solar Orbiter, or from a rover on Mars surface.

GONG observations are also used widely by amateur astronomers to provide a reference and overall guidance for their observations. “The GONG Show” depicting H-alpha and white light images are posted regularly on the amateur astronomy website at https://www.cloudynights.com/. As one example, we show image  reproduced from Sun Ha Session, 2026-04-29 (Frank Lothar Unger) - AstroBin  that uses GONG full disk image as a reference.

GONG data has been incorporated into several apps both for scientific research communities and for public.  This includes the Solar-MACH, a web-tool widely used in the heliospheric community. It obtains, among others, GONG magnetograms using sunpy's fido functionality to use them for the Potential Field Source Surface (PFSS) modelling. The Solmate (solmate.nz), a space weather dashboard for New Zealand, employs a Filament Tracker to highlight filaments on GONG full-disk H-alpha images and watch for eruptions that might send a CME towards Earth. In Australia, an amateur astronomer is working on a project that incorporates GONG H-alpha full-disk images in his star atlas application. Recently, FaktPocasi.cz, a free Czech weather and space-weather website contacted GONG project about their plans to display current GONG observations on their site with additional explanations in plain language of what is happening on the Sun.

Currently, two public competitions are using GONG observations. One is hosted by the Frontier Development Lab (FDL) https://fdl.ai/benchlab-solar-wind-prediction-2026, and is concentrated on prediction of solar wind using magnetograms from different instruments including GONG. The other, Kaggle competition "Solar Filament Segmentation Challenge 2026" is one of seven IEEE Big Data Cup 2026 Data Challenges at the Frontier of AI, Science & Society, https://bigdataieee.org/BigData2026/cup/. It aims at the proper segmentation of solar chromospheric filaments using GONG H-alpha images.

 

Limited Access to NISP Data and Websites

Due to the recent PHP vulnerability, NISP data and web sites are available with limited access.  General public access is restricted until the vulnerability can be mitigated.  Please direct questions to nispdata@nso.edu.

Solar Activity Report: October 12 -18, 2026

 Solar activity remained predominantly at low levels throughout the reporting period, except on 16 October, when activity briefly reached moderate levels following an M1.3 flare from active region 14551, the largest event of the week. During the remainder of the period, activity was characterized by persistent C-class flaring, including several mid intensity C-class events By the end of the week, the majority of active regions had rotated into the western hemisphere, leaving the eastern hemisphere largely devoid of sunspots. This is clearly visible in the accompanying images from the Big Bear Solar Observatory, which show the magnetogram obtained at the end of the week. No Earth-directed coronal mass ejections (CMEs) were observed during this period.

Current helioseismic far-side maps do not reveal any major active regions that are expected to rotate onto the Earth-facing hemisphere within the next few days.

GONG Network in an Extended Low Duty Cycle Phase

GONG operates as a ground-based network of six observing stations distributed around the globe. Although the network routinely provides high-cadence observations with an exceptionally high duty cycle, periods of reduced coverage occasionally occur. The duty cycle can be adversely affected by several factors, including instrument malfunctions at one or more sites, scheduled maintenance activities, and unfavorable weather conditions.

For more than two weeks, GONG has been experiencing persistently low duty cycles, as illustrated in the attached figure. Large gaps in daily coverage are readily apparent. It appears that the ongoing strong El Niño conditions have been contributing to severe weather at two of the network's sites, Big Bear (USA) and Cerro Tololo (Chile), resulting in significant impacts on GONG observations.

The Mauna Loa (Hawaii) site remains offline following the volcanic eruption of late November 2022 and has not yet returned to operational status. In addition, the Learmonth (Australia) site is currently non-operational due to a technical issue. Consequently, the Udaipur (India) and El Teide (Spain) stations have been providing the majority of the network's observations during this period.

The reduced duty cycle has a direct impact on the quality and availability of GONG data products. In particular, when the duty cycle falls below approximately 80%, the far-side helioseismic maps become increasingly noisy and unreliable. Consequently, these maps may not be generated during periods of insufficient data coverage.

NISP produces far-side maps twice each day using GONG Doppler observations to identify active regions and emerging magnetic activity on the far side of the Sun. As a key space weather data product, these maps provide advance warning of potentially active regions before they rotate into Earth view, thereby supporting operational forecasting and mitigating space weather risks.

ngGONG Chilean site visit

This week, October 11-16, 2026, the NSF's National Solar Observatory team traveled to Chile to investigate future locations of second NSO's ngGONG station. Several sites at Cerro Tololo and Cerro Pachón were visited. Attached images show NSO and NOIRLab/CTIO team members at different locations considered for ngGONG station (Photos 1 and 2); the current location of GONG  at Cerro Tololo (photos 3 and 4); the road sign between Cerro Tololo and Cerro Pachón (photo 5). CTIO is also considered as a location for future COronal Solar Magnetism Observatory (COSMO) by High Altitude Observatory (HAO). Photo 6 shows a site-testing solar telescope (SDIMM) at COSMO location.

ngGONG, the next generation Groundbased Solar Observing Network, is a future 6-site network that will replace the aging GONG and enhance its capabilities to include full-vector field observations at different heights in the solar atmosphere, photospheric and chromospheric Doppler velocity imagers, helioseimic and sun-as-a-star instruments. Some stations will be equipped with coronagraphic instruments. The design of ngGONG is funded by the US National Science Foundation as a three year project (Oct 2025-Sep 2028). 

 

Solar Activity Report: October 5 - 11, 2026

 Solar activity varied substantially during the reporting period, rising from low to high and then returning to low levels. Such variability is typical of the declining phase of the solar cycle, when sudden bursts of enhanced activity are common. Approximately 50 C‑class and 7 M‑class flares were observed, with most originating from active region 14549. The strongest event was an M6.7 flare on October 8 from this region, followed by another high‑energy M6.4 flare on October 10.

Other M‑class flares were of lower intensity: an impulsive M1.0 flare from active region 14545 on October 5; M1.4 and M1.8 flares from active region 14549 on October 6; an M1.3 flare from active region 14547 on October 9; and an M1.2 flare from active region 14549 on October 10. All of these active regions were located in the northern hemisphere, which was more active than the southern hemisphere during this period. The X‑ray flux remained near the B/C‑level boundary. The quietest day of the week was October 11, when the flux stayed predominantly in the B‑level. Several CMEs were originated from these flares, some with Earth‑directed components.