Eclipse 12·08·2026

Eclipse Data and Calculation Methodology

The map, simulator and city pages on 2026eclipse.live provide coordinate-based planning estimates for the total solar eclipse of 12 August 2026. They are designed to help readers compare locations, but they do not replace the official eclipse visualiser or a calculation made for the exact final observation point.

Methodology last reviewed: 5 August 2026.

Why exact coordinates matter

An eclipse does not have one universal time for an entire country or province. The start of the partial phase, beginning and end of totality, maximum eclipse, duration, solar altitude and azimuth depend on latitude and longitude.

The difference is especially important near the edge of the path. Two points within the same wider urban area can have different totality durations, and one may be inside totality while another is outside it.

Information displayed by the website

Depending on the selected location and available dataset, the website may display:

  • Whether the eclipse is total or partial.
  • Maximum solar obscuration.
  • Approximate local time of maximum eclipse.
  • Approximate beginning and end of totality.
  • Approximate duration of totality.
  • Solar altitude at maximum.
  • Solar azimuth or viewing direction.
  • A city-centred map and coordinate calculator.
  • Nearby locations for comparison.

Primary astronomical sources

Core eclipse circumstances are checked against recognised astronomical sources, including:

Regional observation arrangements, traffic measures and weather are not inferred from the astronomical dataset. They are researched separately through the authority or organiser responsible for that information.

How a city page should be interpreted

A city page normally uses representative coordinates near the urban centre. Its headline time and duration therefore describe that reference point, not every address within the municipality.

Readers choosing a park, beach, field, viewpoint or event site should click the exact intended location on the map. This is particularly important for short totalities and places close to the path boundary.

Total versus partial eclipse

A location is labelled total only when the reference coordinates fall inside the calculated path of totality. A very deep partial eclipse, including 99% obscuration, is not labelled total.

This distinction is both experiential and safety-critical. Outside totality there is no interval during which direct unfiltered viewing is safe. Inside the path, eye protection may be removed only while the bright solar surface is completely covered, then must be replaced before it returns.

Times and time zones

City pages display local civil time for the location. On 12 August 2026, common labels include CEST in mainland Spain and the Balearic Islands, WEST in mainland Portugal, and GMT in Iceland.

Times may be rounded for readability. A headline such as “approximately 20:29” should not be used as the sole signal for removing eye protection. Observers must respond to the actual phase and should obtain precise contact circumstances for their final coordinates.

Totality duration

Totality duration is the interval between the beginning and end of complete coverage at the selected reference point. It changes across the path and generally becomes shorter toward either edge.

Displayed durations are approximate. Differences of a few seconds may arise from coordinate choice, rounding, the solar and lunar ephemeris used and the treatment of lunar limb topography.

Solar altitude and azimuth

Solar altitude is the angle of the Sun above the astronomical horizon. Azimuth identifies its compass direction. These values help users understand where to look and whether a hill, building, tree, mountain or layer of low cloud may block the view.

They do not model every local obstruction. A calculated altitude of 3° does not guarantee that the Sun will be visible from a particular street or beach. The practical horizon should be checked in person or with suitable topographic tools before eclipse day.

Across Spain the solar altitude during totality varies substantially. It is higher in the northwest and much lower in eastern Spain and the Balearic Islands. For that reason, the website avoids applying one national altitude to every Spanish location.

Path-edge uncertainty and lunar terrain

The Moon’s visible edge is not perfectly smooth. Valleys and mountains along the lunar limb can affect the exact contact times and practical path boundary. Near the edge, small differences in position can therefore matter.

People who want a dependable period of totality should choose a verified point comfortably inside the path rather than relying on an approximate boundary line.

Map limitations

The interactive map is a planning tool. Digital map layers, markers, paths and administrative boundaries may contain small positional differences. A marker does not itself confirm:

  • Public access.
  • Permission to remain on the land.
  • Parking availability.
  • An unobstructed horizon.
  • Event capacity.
  • Road access on eclipse day.
  • Safe weather or fire conditions.

Weather information

Historical cloud frequency is labelled as climatology rather than a forecast. A reliable local decision should be based on official short-range forecasts, satellite imagery, current observations and the western horizon during the final days.

For Spain, AEMET is the principal national meteorological source. Radar is useful mainly for precipitation; an empty radar image does not prove that the sky is cloud-free.

Official events and observation points

Astronomical suitability does not make a location an official observation point. A place is described as official, organised, free, reservation-required or paid only when the responsible authority or organiser provides that information.

Because arrangements can change, local pages include source links and review dates. Readers must check the latest access, capacity, booking, transport and safety instructions before travelling.

Review and corrections

Prominent city and regional pages are reviewed when new authoritative information becomes available. If two sources disagree, the page should explain the difference or use the responsible national or local authority for the relevant claim.

To report a calculation discrepancy, use the contact page and include:

  • The page URL.
  • The coordinates used.
  • The displayed result.
  • The expected result.
  • The authoritative comparison source.

All values on 2026eclipse.live are supplied for planning and education. Follow the current instructions of astronomical authorities, event organisers, traffic agencies, emergency services and land managers.