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2017 August 21 Total Solar Eclipse

If, during the progress of a total [solar] eclipse, the gradually diminishing crescent of the sun is watched, nothing remarkable is seen until very near the moment of its total disappearance. But, as the last ray of sunlight vanishes, a scene of unexampled beauty, grandeur, and impressiveness breaks upon the view. The globe of the moon, black as ink, is seen as if it were hanging in mid-air, surrounded by a crown of soft, silvery light, like that which the old painters used to depict around the heads of saints. Besides this "corona", tongues of rose-colored flame of the most fantastic forms shoot out from various points around the edge of the lunar disk. Of these two appearances, the corona was noticed at least as far back as the time of Kepler; indeed, it was not possible for a total eclipse to happen without the spectators seeing it. But it is only within a century that the attention of astronomers has been directed to the rose-colored flames, although an observation of them was recorded in the Philosophical Transactions nearly two centuries ago. They are known by the several names of "flames," "prominences," and "protruberances."
— Simon Newcomb. 1878. Popular Astronomy. New York: Harper & Brothers. p. 252

On 2017 August 21, a total solar eclipse was visible to fortunate observers in the United States along a narrow band, approximately 73 miles (118 km) wide, that crosses twelve states from Oregon to South Carolina.

Calculate local circumstances

Major U.S. cities in the path of totality: Casper, WY; Kansas City, KS; Jefferson City, MO; Kansas City, MO; Lincoln, NE; Salem, OR; Columbia, SC; Greenville, SC; Nashville, TN, St. Louis, MO; Charleston, SC

Use the form below to calculate the local circumstances. To find coordinates of cities or towns in the U.S. or its territories, or to convert between Degrees-Minutes-Seconds (DMS) and Decimal Degrees, use the respective buttons.

Eclipse: 2017 August 21 (Total)

Location Coordinates in decimal degrees, North and East are positive. For example: 38.9072, -77.0369

Location Label Custom label for printed output. For example: Washington, DC

Need coordinates?  Try NGA's GEOnet Names Server (GNS)
Need U.S. coordinates?  Try the USGS Geographic Names Information System (GNIS) .

Height (-90 to 10999 meters)
meters

For other eclipses, try our Solar Eclipse Computer. Times are given in UT1; for help converting them to local time, see U.S. Time Zones. Notes on the local eclipse circumstances are located at the bottom of this page.

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View US map and circumstances

His Majesty's Nautical Almanac Office (HMNAO), United Kingdom Hydrographic Office provides a 2017 total solar eclipse map. The map contains detailed information about the eclipse for selected US cities, including local circumstances, animations, and diagrams. Please click on the image to visit the full map.

link to a map of the 2017 Solar Eclipse circumstances in the US
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View global map and circumstances (Eclipses Online Portal)

The Eclipses Online Portal provides diagrams and animations showing the global circumstances and local circumstances at selected locations. The Portal is a joint effort with His Majesty's Nautical Almanac Office , United Kingdom Hydrographic Office.


Times are given in UT1; for help converting them to local time, see World Time Zone Map.

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View global visibility map (The Astronomical Almanac)

Preliminary Eclipse Visibility Map from The Astronomical Almanac (explanation of map).

For visibility maps of other eclipses, see Eclipses of the Sun and Moon.

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View circumstances at Shawnee National Forest , Illinois, site of maximum eclipse

Local circumstance diagram for the location of maximum duration of totality (from HMNAO).

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General eclipse resources

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Notes

The table of local circumstances gives the UT1 time of each eclipse "event" that is visible from the location. The altitude and azimuth of the Sun at each of the events is given as well. The azimuth is reckoned eastward from North. The altitude is corrected for refraction assuming standard atmospheric conditions.

The computation of Eclipse Local Circumstances is started by iteratively computing topocentric positions of the Sun and Moon to find the time of Maximum Eclipse. Another series of position computations is performed going backwards and forwards from the time of Maximum Eclipse to find the times of contacts. The solar and lunar angular diameters are calculated at each position using radius values adopted by the International Astronomical Union (Sun 696000 km; Moon 1737.4 km) to determine if contact conditions have occurred. Lunar limb profiles and center of mass/center of figure corrections are not used.

After contact times have been computed, a check is made to determine if Sunrise and/or Sunset occurred during the course of the eclipse. If so, the time of Sunrise and/or Sunset is computed.

The body of the table contains the time of each contact point, the Sun's topocentric position at that time, and its Position and Vertex Angles. The time of sunrise or sunset is also noted in the table if it occurs during the eclipse. The summary at the bottom contains the Duration, Magnitude, and Obscuration.

The Position Angle of a given contact point on the solar limb is measured eastward (counterclockwise) around the solar limb, from the point on the Sun that is farthest north.

Vertex Angle is similar to Position Angle, except that it is measured from the point on the Sun that has the highest local altitude.

Duration is the amount of time from the beginning of the eclipse to the end.

Duration of Totality is the amount of time from the beginning of the central phase eclipse to the end of the central phase. For an annular solar eclipse, it will read Duration of Annularity.

Magnitude of the eclipse is the fraction of the apparent diameter of the solar disk covered by the Moon at the time of greatest phase, expressed in units of solar diameter.

Obscuration is the percentage of the area of the apparent solar disk obscured by the Moon at maximum eclipse.

Additional eclipse defintions are available in the Astronomical Almanac Glossary .

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