JavaScript Lunar Eclipse Explorer for North America

Fred Espenak

Instructions

Note: Your web browser must have Javascript turned on to generate eclipse predictions with this web page.

The JavaScript Lunar Eclipse Explorer can compute the local circumstances for every lunar eclipse visible from a city for any century from -1999 to 3000 (2000 BCE to 3000 CE). Just follow these instructions:

  • Section 1 - Select a city from the drop-down menu or manually enter the geographic coordinates and time zone.
  • Section 2 - Choose the eclipse types to include in the search (All eclipses, partial and total eclipses, or only total eclipses).
  • Section 3 - Choose the desired century by clicking the button.
  • Section 4 - A table will be generated giving the local circumstances for every eclipse visible for the selected city and century.

All times are displayed in local time using the value from the Time Zone field in Section 1 (you must add 1 hour if Daylight Saving Time is in effect).

Predicted events shown in gray occur below the horizon and can not be seen from the selected location. The calendar date of an eclipse refers to the start time of the eclipse, even if the Moon is below the horizon at that time. If an eclipse begins before midnight and ends after midnight, the latter phases occur on the following calendar date.

For more information about the local circumstances table, see Key to Javascript Lunar Eclipse Explorer.

Although the start and end times of penumbral phases are listed in the predictions below, they are only of academic interest. These events are not visible to the eye. For detailed descriptions, see Visual Appearance of Lunar Eclipses. More information is available on the how, what, when, where, and why of lunar eclipses at Lunar Eclipses for Beginners.

The JavaScript Solar Eclipse Explorer is a similar web tool for determining the visibility of solar eclipses from any city.

Section 1: City Coordinates

Choose city, or enter coordinates:

Name:
Latitude: deg min sec
Longitude: deg min sec
Altitude: meters
Time Zone:

Section 2: Eclipse Type Search Criteria

Choose eclipse types for search:

All eclipses Partial and Total Total

Section 3: Century Selection

Choose a century* (click on button):

* Negative years are equivalent to the year BC minus 1 year (See: Dating Conventions ). 













Section 4: Eclipse Predictions








Events shown in gray occur below the horizon and are not visible.


The calendar date of an eclipse refers to the start of the penumbral eclipse, even if this phase is not visible (i.e., Moon is below the horizon). 
If an eclipse begins before midnight and ends after midnight, the latter  phases occur on the following calendar date. 



Negative years are equivalent to the year BC minus 1 year (See: Dating Conventions ). 








Acknowledgments



The Javascript Lunar Eclipse Explorer was developed by Chris O'Byrne and Fred Espenak. 
It features drop-down menus for city coordinates and buttons to select any century from -1999 to 3000 (2000 BCE to 3000 CE). 
It can be used to explore the frequency and circumstances of all lunar eclipses visible from any location on Earth. 




The Besselian elements and values of ΔT used in Javascript Lunar Eclipse Explorer are the same as those used by the Five Millennium Canon of Lunar Eclipses: -1999 to +3000. 
For the purposes of calculating eclipse circumstances from a given place, the growing uncertainty in the value of ΔT and the corresponding longitude become unacceptably large outside time period of -1999 to 3000 (2000 BCE to 3000 CE). 




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




"Eclipse Predictions by Fred Espenak and Chris O'Byrne (EclipseWise.com)"





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