Solar Eclipse Circumstances Calculator

Partial Solar Eclipse of 0817 Jul 18

Fred Espenak

Introduction

The Solar Eclipse Circumstances Calculator computes the eclipse circumstances for all major cities in a geographic region for the Partial Solar Eclipse of 0817 Jul 18 .

Simply follow these instructions:

  • Section 1 - Select a Output Time (either Local Standard Time, Daylight Saving Time, or Universal Time (UT1)).
  • Section 2 - Select Geographic Region coordinates.
  • Section 3 - A table will be generated giving the eclipse circumstances for all cities in the selected geogrphic region.

The generated eclipse circumstances table lists important information about the eclipse for each city:

  • The type of eclipse seen from each city (P=Partial, A=Annular, T=Total)
  • The times when the partial eclipse begins and ends.
  • The times when the total (or annular) eclipse begins and ends.
  • The time of maximum eclipse.
  • The altitude on the Sun above the horizon (degrees) at each of these times.
  • The Eclipse Magnitude at maximum eclipse.
  • The Eclipse Obscuration at maximum eclipse.
  • The Eclipse Duration of either the total or annular phase (if any).

Note than country names for cities appear as the ISO 3-Letter Country Code Abbreviations (Wikipedia).

For more information about the eclipse circumstances table, see the Key to Solar Eclipse Circumstances Calculator page.

Section 1: Select Output Time

Select the Output Time in which you wish the eclipse circumstances to be displayed.
Choose either Local Standard Time, Daylight Saving Time (DST), or Universal Time (UT1):

Local Standard Time Daylight Saving Time (DST) Universal Time (UT1)

Note: Do NOT choose Local Daylight Saving Time (DST) unless DST is in effect during the eclipse in at least some portion of the geographic region selected in Section 2. Cities that never use DST will be unaffected in either case. See Daylight Saving Time by Country (Wikipedia) for more information.

Section 2: Select Geographic Coordinates

Choose either option A (file of citiy coordinates in a geographic region) or B (manually enter city coordinates):

A: Select Geographic Region

Choose a Geographic Region (of city coordinates) to generate eclipse circumstances table (click on button):

B: Manually Add One or More Locations


Location name
d m s Latitude ( South)
d m s Longitude ( East)
Elevation (meters)
Select the default local time zone
Enable daylight saving time offset for this location?

Additions to lists of cities will appear first in the Section 3 report as soon as you add the location. If the location does not appear displayed list, there is no eclipse there. Check your input carefully before adding new additions. You can always remove the last entry made and start again if you make a mistake.

Section 3: Solar Eclipse Local Circumstances


A time followed by "(r)" means the event is already in progress at sunrise, while a time followed by "(s)" means the event is still in progress at sunset. In such cases, the times and circumstances given are for sunrise or sunset, respectively.

Note than country names for cities appear as the ISO 3-Letter Country Code Abbreviations (Wikipedia).

See Daylight Saving Time by Country to see when and where DST is observed. Send any DST corrections to cities appearing in the Solar Eclipse Circumstances Calculator to EclipseWise.

Links for the Partial Solar Eclipse of 0817 Jul 18

Links to Additional Solar Eclipse Predictions

Eclipse Predictions

Predictions for the Partial Solar Eclipse of 0817 Jul 18 were generated using the JPL DE406 solar and lunar ephemerides. The lunar coordinates were calculated with respect to the Moon's Center of Mass. Although the predictions are first calculated in Terrestrial Dynamical Time (TD), they are then converted to Universal Time (UT1) as presented here. The parameter ΔT is used to convert between the two times (i.e., UT1 = TD - ΔT). ΔT has a value of 2794.4 seconds for this eclipse.

Acknowledgments

Some of the JavaScript code in the Solar Eclipse Circumstances Calculator is based on the Solar Eclipse Calculator created by Deirdre O'Byrne and Stephen McCann in 2003. The original calculator predicted the local circumstances for any single eclipse over the period 1970 to 2039 for a single geographic position supplied by the user. Bill Kramer (Eclipse-Chasers.com) has expanded this code to work with dozens of cities in the geographic region of the user's choice.

Permission is freely granted to reproduce this data when accompanied by an acknowledgment:

"Eclipse Predictions by Fred Espenak (EclipseWise.com)"

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