Sculpture of the Laocoön and solar eclipses

 The Uffizi Gallery (Florence, Italy),  one of the largest and best-known museums in the world, holds a collection of priceless works from the period of the Italian Renaissance. One of these is the Laocoön sculpture by Baccio Bandinelli (Florence 1493-1560). 

The sculpture depicts the Trojan priest and his sons crushed by sea serpent sent by Poseidon to stop him from revealing the deception of the Trojan horse devised by Odysseus to help the Greek army enter the city of Troy. One can find more about the history of this sculpture at the Uffizi web site. 

The stature rests on its original pedestal. Two sides of this pedestal show identical reliefs, which caught the eye of this astronomer. What the reliefs show is the geometry of total solar eclipse. Two half-spheres represent Sun (surrounded by spiky corona) and the Moon. Two lines connecting the edges of the Sun and Moon mark the outer boundary of umbra, the darkest part of shadow cast by Moon blocking the sunlight. Two other lines show angles at which the lunar disk would be seen from each side of umbra.

By the way, next solar total eclipse will take place on 12 August 2026. It starts in Greenland, passes over North Atlantic Ocean, parts of Iceland, Spain, and it ends in the Mediterranean Sea. In Florence, it will be a partial solar eclipse with maximum obscuration of 92.07%. Several teams of scientist from the US National Solar Observatory will travel to Spain to observe this total eclipse. We will post updates from these eclipse expeditions later. 

Solar Activity Report: July 20 -26, 2026

 Solar activity remained mostly at low levels during the past week.  The X‑ray intensity hovered between high B-class and low C-class. B-class is defined as the X-ray intensity (brightness) below 10^-6 W/m^2, and C-class starts at 10^-6 W/m^2 as measured in 1-8 Angstrom wavelength range. Most of the activity originated from active region 14493, which produced five M‑class flares. Three impulsive events, M2.5, M1.1, and M3.4, occurred on July 20. Two additional M-class flares, M1.9 and M3.6, were recorded on July 21 and July 22, respectively, with the M3.6 event being the strongest of the week. Another notable event was an M3.2 on July 26 from active region 14494. No Earth‑directed CMEs were observed during this period.

Helioseismic maps of the far hemisphere do not show any significant magnetic activity.

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.

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*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.