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.

ngGONG developments

Last week, Sep 30-Oct 1, 2026, the NSF's National Solar Observatory team traveled to the Big Bear Solar Observatory (BBSO) in California to discuss future location of one of NSO's ngGONG stations. 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). Attached image shows the NSO and BBSO/NJIT team members at the approximate location of future ngGONG station. The site is located on the shore of Big Bear Lake between GONG and SOLIS stations. 

Solar Activity Report: September 21 - 27, 2026

 Solar activity remained at low levels during the reporting period, with X‑ray flux generally at mid‑B levels except for a few impulsive, low C‑class flares. Several active regions were present on the visible disk, but most remained relatively quiet, producing little to no significant flaring activity aside from occasional low‑intensity C‑class events. The strongest flare was an impulsive C3.1 event on September 26 from the active region 14534, located near the north-west quadrant. No Earth‑directed CMEs were identified in available coronagraph imagery.  

The most recent helioseismic map of the far side shows no evidence of significant active regions that are likely to rotate onto the Earth‑facing hemisphere over the next few days.

GONG at Udaipur is back on line

The report from India received on 24 Sep. 2026, indicated that "the sky continues to be clear and favorable for observations since last couple of days. Hence we would like to resume UDGONG observations".  Following to this, the startup procedure was sent to the local support staff. The turret was unstowed early today (25 Sep 2026). The instrument and data computers were rebooted, and GONG/UD station came on-line. Indian monsoon is over! Attached image is one of the first H-alpha images taken after the monsoon.

Time-domain Astronomy

With the NSO team moving the archive of the NSO at Sac Peak historical data to Colorado this week, one may ask the questions of "why do we need to preserve old data" and "what can be learned from it"?

Recent article by Dr. Hisashi Hayakawa and his co-authors highlights the importance of historical data for studying past solar activity. They found that the observations of solar eclipse on 13 May 1733 by Swedish astronomer and mathematician Birger Wassenius may have been the very first observations of so-called rush-to-the-poles prior to the solar polar field reversal. These Wassenius ' observations also suggest that in 1733, the Sun was not in an activity minimum as previously thought. The article was highlighted by the AAS Nova in A New Look at a Centuries-Old Solar Eclipse.