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.