Frequently asked questions

Although solar eclipses seem extremely rare – because they are not often visible from the same spot on the planet – they actually occur quite frequently. Every year, there can be between 2 and 5 solar eclipses across the globe. That said, not all of them are total eclipses: some are partial or annular, and sometimes the total eclipse is only visible from a very narrow strip.
The most common scenario is two solar eclipses per year. Three or four are less frequent, and five solar eclipses in a single year is a very rare event that occurs only a few times per century.
However, as the Moon’s shadow is very small, the probability of the eclipse passing over exactly the same spot is very low. For this reason, at any given fixed location on Earth, a total eclipse occurs only once every 300 to 400 years, or less.

Extraordinary astronomical events often give rise to misinformation (claims that eclipses emit toxic radiation, harm pregnant women or herald disasters). It is vital to remember that an eclipse is a purely mechanical and optical phenomenon: it is simply a projected shadow, without any abnormal emission of energy. The best way to combat these myths is to turn to science and consult official sources (such as the IGN or the SEA (could we include the links here?)).

During the sudden drop in light and temperature that occurs during an eclipse, it is common to observe changes in the environment: some birds fall silent or return to their nests, and nocturnal insects become active, believing that night has fallen. Ethology studies this phenomenon, and various citizen science projects are currently being promoted in which the public can contribute by recording and sharing observations of wildlife reactions and meteorological changes in their local environment.

Ancient astronomers were able to predict eclipses, even though they did not have as much knowledge as we do today. Their methods were based on centuries of observing the sky, numerical cycles and very precise records.
Although the Egyptians had a highly advanced calendar, they left hardly any written records of solar eclipses. This was probably because they considered them to be a sign of bad luck, so they avoided talking about them. Their knowledge was based more on observation and mythology than on mathematical models for predicting them.
The Babylonians were the most accurate predictors of eclipses before the Greeks. They based their predictions on centuries of observing the sky and on highly detailed records on clay tablets. This is how they discovered the Saros cycle (which states that eclipses recur every 18 years, 11 days and 8 hours), showing that eclipses recur approximately every 18 years. This enabled them to foresee when an eclipse might occur, although they also interpreted them as omens sent by the gods.
The Maya (250–900 AD) developed a highly accurate system of astronomy based on calculations, calendars and lunar cycles. They carefully observed the movements of the Sun and the Moon and used a complex calendar system to predict eclipses. The Dresden Codex contains tables listing hundreds of lunar cycles, which enabled them to achieve a level of accuracy comparable to that of modern methods.

Astronomers first have to work out the geometry and mechanics of how the Earth and the Moon orbit the Sun under the influence of the gravitational fields of these three bodies. Using Newton’s laws of motion, they mathematically calculate the motion of these bodies in three-dimensional space, taking into account the fact that these bodies have a finite size and are not perfect spheres. Scientists then plug the current positions and velocities of the Earth and the Moon into these complex equations, and programme a computer to ‘integrate’ these equations forwards or backwards in time in order to calculate the relative positions of the Moon and the Sun as seen from the Earth’s perspective.
Eclipses are specific configurations of these bodies that can be identified by computers. Current eclipse predictions have a timing accuracy of less than one minute over a period of hundreds of years.

The phenomenon of eclipses is a marvellous example of how the laws of physics and orbital geometry combine with an astonishing cosmic coincidence.
The Sun is about 400 times larger than the Moon, but it is also approximately 400 times further away. This coincidence means that both appear to be almost the same size in the sky, allowing the Moon to fit almost perfectly over the Sun during a total eclipse.

Total solar eclipses last between 10 seconds and around seven and a half minutes. Over the 12,000-year period from 4000 BCE to 8000 CE, the longest total solar eclipse will occur on 16 July 2186 and will last seven minutes and 29 seconds. Its path will stretch across Colombia, Venezuela and Guyana. The shortest total solar eclipse occurred on 3 February 919 CE, and lasted just nine seconds.

The Earth rotates on its axis towards the east, which means that the Moon, the Sun and the stars appear to move from east to west across the sky. The Moon orbits the Earth in the same direction as our planet rotates — towards the east — but the Moon’s movement along its orbit is small compared to the Earth’s daily rotation, making it difficult to notice the Moon’s eastward movement. However, during a solar eclipse, it is easier to observe this movement as the Moon passes in front of the Sun from west to east. The Moon’s shadow follows the same direction, tracing a path eastwards across the Earth’s surface.

A solar eclipse occurs when the Moon passes directly between the Sun and the Earth. When the Moon completely blocks the Sun, it is called a total solar eclipse. When the Moon blocks only part of the Sun, it is called a partial eclipse. An annular eclipse is a special type of partial eclipse that occurs when the Moon blocks the entire Sun except for a small ring around the edge. Sometimes, a solar eclipse can appear as an annular eclipse in some places and as a total eclipse in others, as the Moon’s shadow moves across the Earth’s surface. This is known as a hybrid eclipse. You can find out more about the types of solar eclipse here. ( https://ciencia.nasa.gov/sistema-solar/lo-que-necesitas-saber-sobre-los-eclipses-solares/ )

If we look towards the Sun from Earth, the Moon passes ‘in front of’ the Earth every 28 days. We might therefore think that there should be a solar eclipse every month, but this is not the case.
Although we have a new moon every month, eclipses do not occur every lunar cycle because the Moon’s orbit is not perfectly aligned with the Earth’s orbit around the Sun: the plane in which the Earth orbits the Sun and the plane in which the Moon orbits the Earth do not coincide exactly, but are slightly tilted relative to one another, forming an angle of 5 degrees. So, most of the time, the Moon passes slightly above or below the Sun as seen from Earth.

The study of the innermost part of the corona – the Sun’s outer atmosphere, which is only visible during total solar eclipses – is key to answering fundamental questions about how heat and energy are transferred from the Sun to the solar wind, which is the constant stream of particles that the Sun ejects into the solar system. The solar wind can affect technology on Earth and astronauts in space, so understanding how the solar wind is accelerated on the Sun can help predict its impacts on our planet. (https://www.nasa.gov/podcasts/universo-curioso-de-la-nasa/todo-sobre-el-sol/)
Total solar eclipses provide an opportunity to study the Earth’s atmosphere under unusual conditions. In contrast to the global change in light that occurs every day at sunset and sunrise, a solar eclipse alters the illumination of the Earth and its atmosphere within a comparatively small region covered by the Moon’s shadow.
This localised blocking of solar energy allows us to study the effects of the Sun on our atmosphere, particularly in the upper atmosphere, where the Sun’s energy creates a layer of charged particles known as the ionosphere. Understanding this region is important because it is home to many satellites in low Earth orbit, as well as communications signals — such as radio waves and the signals that power GPS systems — and changes occurring there can have significant impacts on our technology and communications systems

Eclipses occur in patterns. The Saros series is a cycle of 223 lunar months that has been used to predict eclipses for thousands of years. In a Saros series, exactly nine years and 5.5 days after any lunar eclipse, a solar eclipse will occur, and vice versa. Approximately 6,585.3211 days, or 18 years, 11 days and 8 hours, after an eclipse, the Sun, Earth and Moon return to the same relative positions, and an almost identical eclipse occurs. These identical eclipses are part of the same Saros cycle, and the time between the two eclipses is called a Saros.
For eclipses belonging to the same Saros cycle, the Moon will be at the same node and at the same distance from the Earth. Because an eclipse in a Saros cycle occurs just 11 days later in the year than the previous one, the Earth will be at almost the same distance from the Sun and tilted relative to it in almost the same orientation (in the same season) as it was during the previous eclipse in that cycle. Each path of totality for a solar eclipse looks similar to the previous one, but is shifted 120 degrees to the west.

The difference lies in which celestial body blocks the path of the light.
- Solar eclipse: The Moon passes exactly between the Earth and the Sun, casting its shadow onto our planet and obscuring the Sun’s disc. It only occurs during the new moon phase.
- Lunar eclipse: The Earth comes between the Sun and the Moon, blocking the sunlight that illuminates our Moon and casting a shadow over it. It only occurs during the full moon phase.

The path of totality for the 2026 eclipse in Spain is unusually wide and will be visible across much of the country, making it an extraordinary event for observers.

Eclipses can be predicted because the movements of the Sun, the Earth and the Moon follow very regular and predictable patterns. The Moon’s orbit around the Earth and the Earth’s orbit around the Sun are fairly stable and follow well-known laws of physics. This makes it possible to calculate exactly when the Moon, the Earth and the Sun will align in such a way that an eclipse occurs.

It is said that the Greek philosopher Thales of Miletus was the first to predict a total solar eclipse. According to tradition, he predicted the eclipse of 28 May 585 BC. Although this may be a legend, the historian Herodotus recounts that this eclipse occurred during a battle and led the combatants to make peace, as they interpreted it as a divine sign.

Yes, our website provides the general public and educators with a repository of teaching materials. You can find and download visual resources, explanations and guides free of charge on our website: Educational resources on the Sun and eclipses.

At national level, the website of the Interministerial Commission for the Trio of Eclipses and its Scientific and Advisory Committee compiles information from across the country; this site will also bring together and highlight all the activities taking place in the Principality of Asturias, such as the programme of talks, workshops and public outreach events.

The accuracy of the viewing points is directly linked to the bands of totality or annularity shown on the map. The IGN provides detailed tools that allow you to explore Spain, province by province, to find the best coordinates. You can access these resources on this page.

Check the programme and the latest news on the website. If you’re organising an activity, use the official guides and materials to ensure your safety messages are consistent.

In the ‘Resources and materials’ section, you’ll find guides, checklists and educational materials. The library will be expanded as the date approaches.

This is a standard for solar observation filters intended for visual use (glasses/viewers). It requires that the product bears the ISO 12312-2 marking and specifies that you should check that they are in good condition before use.

Many shuttle buses will run until 11.00 pm, and the main metropolitan services until 1.00 am.

How to put on protective glasses (Step by Step)
1.- Keep your prescription glasses on: Do not take them off, as they will allow you to see the eclipse clearly.
2.- Put the eclipse glasses on top: Wear the certified eclipse glasses over your usual prescription glasses.
3. A comfortable fit: Make sure the arms of the eclipse glasses go over or around the sides of your prescription glasses so that both pairs sit securely.
4. Check for gaps: Make sure no sunlight is coming in from the sides, top or bottom of the glasses.

The ‘Look Down’ Safety Protocol
To ensure your safety, always follow this sequence:
1.- Look at the ground: Put on your eclipse glasses whilst looking at the ground.
2.- Look up: Only when your protective glasses are securely in place should you lift your head to look at the Sun.
3.- To remove your glasses: First look down at the ground, and only then take them off.

Additional tips
- Check the glasses: Before using them, check that they have no tears, holes or scratches. If they are damaged, do not use them.
- Certification: Make sure they are certified to ISO 12312-2:2015.
- Alternative: If you find the cardboard glasses uncomfortable to wear over your prescription glasses, you can buy handheld solar viewers and hold them in front of your prescription glasses.
- Do not use with a telescope: Never look through a telescope or binoculars whilst wearing only the eclipse glasses; you need special filters for the instrument.

The total solar eclipse will take place on Wednesday 12 August 2026
Approximate times:
Start of partial eclipse: ~19:30
Total eclipse: ~20:26 – 20:29
End: ~21:20
The total darkness phase will last around 1 minute and 40–50 seconds, depending on the exact location

The best viewing location and the exact time depend on the path of the Moon’s shadow across the Earth’s surface, which varies with every eclipse. Visibility (total, partial or none) changes drastically from one town to another. To find out the precise start, peak and end times of the event at your exact location, we recommend consulting the interactive map.

The eclipse will occur at a very low elevation across the whole of Spain (the lower the elevation, the further east you are), so to enjoy an unobstructed view of the phenomenon, it is highly recommended that you find a spot where the western horizon (where the Sun will set) is clear of obstacles such as hills, buildings, trees, etc.

It is not advisable to use your mobile phone as a ‘viewfinder’ for the Sun for any length of time. If you take photographs of it, do so with caution, without looking directly at the Sun and avoiding pointing the camera at it for long periods at a time. Focus on capturing the atmosphere and the surroundings.

NO. Ordinary sunglasses are not suitable. Nor are X-rays, CDs, tinted glass or photographic film. ‘Homemade’ filters are strongly discouraged.

The pinhole projector (or camera obscura) is a very popular and safe method. All you need are two sheets of opaque card. Make a pinhole in the centre of one of them. Stand with your back to the Sun and let the light pass through that small hole to project the image of the Sun onto the second piece of card, which will act as a screen. The further away you place the ‘screen’, the larger the projected image of the Sun will appear. You can find step-by-step instructions on the National Geographic Institute’s general observation page.

During a total eclipse, when the Sun is completely covered (the ‘totality’ phase), you can look at it very briefly with the naked eye, but only whilst the solar disc is 100 per cent obscured. As soon as the first light reappears, you must look away or use suitable solar filters.

To observe a solar eclipse safely, you need certified solar filters, such as those used for welding or glasses complying with the ISO 12312-2:2015 standard, or you can project the image of the Sun indirectly (for example, using a homemade camera obscura or a pinhole projector).

In any case, observing the Sun – even with a good filter – is dangerous, as you might lose concentration and end up looking at it without a filter. For this reason, there is nothing safer than projecting the image of the Sun.

You can consult the technical safety requirements drawn up by the Scientific and Advisory Committee for the Eclipse Trio (CCATE) here: Quality criteria for eclipse glasses.

Generally speaking, you should not look at the Sun without protection during the partial phases. In a totality zone, you can only look at the Sun without filters during the brief period when it is completely covered. As soon as the first glimmer reappears, put your protection back on.

The best and safest place to buy them is from specialist shops selling astronomical equipment or reputable opticians. To check that they are certified, make sure they are stamped with the ISO 12312-2:2015 certificate and the European CE mark, the manufacturer’s logo and the instructions. You can find full details on how to avoid counterfeits in this document: Quality criteria for eclipse glasses.

No. Clouds or a low sun do not guarantee safety. If the sun is visible, the rule still applies: approved protection or a shade.

It depends on the manufacturer and the condition of the material. If they are damaged (scratches, holes, peeling), they must not be used. If you are unsure, replace them with new ones or use a projection.

No, never without the proper protection. Pointing a camera or mobile phone lens directly at the Sun without an approved neutral-density solar filter can melt or irreversibly damage the device’s sensor in a matter of seconds. Furthermore, if the camera has an optical viewfinder, the concentrated light will cause serious burns to the human eye. Special filters (such as Mylar or Baader film) must always be placed in front of the lens, never behind it.

You must not look directly at the Sun during an eclipse for the same reason that you must not look at it under normal conditions. But the eclipse can trick you into thinking it is safe.
During an eclipse, the ambient light dims and your pupils dilate. Although it may seem safe to look, such wide-open pupils allow more radiation to enter all at once, and the damage can be even greater.
The Sun continues to emit dangerous radiation even when it is partially covered by the Moon. It emits very intense ultraviolet and infrared radiation. Ultraviolet light burns the cells of the retina, and infrared radiation heats and damages the tissues of the eye, even though you may not notice it because the retina has no pain receptors. The result can be solar retinopathy, an irreversible injury that causes blind spots or permanent loss of vision.

No. Sunglasses protect your eyes, but they do not make an optical instrument safe. For binoculars or a telescope, you need a specific, correctly fitted front solar filter. Otherwise, use projection.

Projection (camera obscura/pinhole or screen projection) is the safest and most controllable option for groups, particularly those involving children.

Extreme caution is required. The lenses of telescopes and binoculars act as giant magnifying glasses that concentrate the Sun’s heat, which can cause instant and irreversible blindness. An approved solar filter must always be fitted to the front aperture of the instrument (where the light enters) and be securely fastened. Never use standard eclipse glasses to look through a telescope, as the concentrated heat will melt the glasses in a second. You can find all the detailed technical instructions here: How to observe eclipses (IGN)

Indirect observation is the safest method, as you never look directly at the Sun, but rather at its shadow or reflection. It involves projecting the image of the Sun onto a smooth surface (such as a sheet of white card) by passing it through a small hole. You can use everyday items such as a kitchen slotted spoon, or make a simple camera obscura out of cardboard. The IGN provides detailed instructions on how to set up these systems easily and safely: How to observe eclipses (IGN).

On the official website of the Asturias Transport Consortium and on this page once the final timetables have been published.

- Your local council
- Tourist offices in the Principality of Asturias Network of Natural Areas (RENA) (RENA)
- Asturias Trade Fair (FIDMA) The Regional Ministry of Social Rights will distribute glasses to the most vulnerable groups (children and the elderly), and the Regional Ministry of Science, in collaboration with the University of Oviedo, will hand them out at trade fairs and public awareness events.