Lunar Eclipse Computer

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You can obtain the circumstances of recent and upcoming lunar eclipses for any location by following these simple steps:

Decide on which form below to use. If you want local circumstances for cities or towns in the U.S. or its territories, use Form A. For other locations, use Form B.
Select the eclipse from the first pop-up list in the form that you are using.
Specify the location, using the fields provided in the form.
Click the "Get data" button at the end of the form to compute a table of local circumstances.
Be sure to read Notes on the Data (on this page beyond the two forms) for an explanation of the items in the table.

For general information on eclipse circumstances and visibility, see Upcoming Eclipses of the Sun and Moon.

Form A - U.S. Cities or Towns

Eclipse:

State or Territory:

City or Town Name:

The place name you enter above must be a city or town in the U.S. The place's location will be retrieved from a file with over 22,000 places listed. Either upper- or lower-case letters or a combination can be used. Spell out place name prefixes, as in "East Orange", "Fort Lauderdale", "Mount Vernon", etc. The only exception is "St.", which is entered as an abbreviation with a period, as in "St. Louis". You need only enter as many characters as will unambiguously identify the place.

Form B - Locations Worldwide

Eclipse:

Place Name Label:

The place name you enter above is merely a label for the table header; you can enter any identifier, or none (avoid using punctuation characters). The data will be calculated for the longitude and latitude you enter below.

Longitude: east west degrees minutes

Latitude: north south degrees minutes

Time Zone: hours east of Greenwich west of Greenwich

For locations that require it, the time zone can be entered in hours and a fraction. For example, for locations in India, the time zone may be entered as 5.5 hours east of Greenwich. The time zone field can accommodate up to five characters.

Notes on the Data:

The table of local circumstances gives the local time of each eclipse "event" that is visible from the location. The times are the same as those published in The Astronomical Almanac, adjusted to the specified time zone. The altitude and azimuth of the Moon 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 table also gives the time of moonrise immediately preceding, and the time of moonset immediately following, the eclipse. At high latitudes, either or both of these times may be missing from the table. The accuracy of the rise/set times decreases as the latitude approaches +/- 90 degrees. For information on the definitions of terms used, see Rise, Set, and Twilight Definitions

The times of all events are presented in the standard time of the place requested, using the current time zone of the place (Form A), or the specified zone (Form B). Daylight time is applied to times for places in the U.S. (Form A) when and where appropriate.

If you need to check the times of sunrise and sunset around the time of the eclipse, see Complete Sun and Moon Data for One Day.

Need other kinds of astronomical information? Start at our home page.

Back to . . . top Form A Form B

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