Moondial

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Moondial at Queens' College, Cambridge, showing the table of corrections for the phase of the moon Moondial queens college.jpg
Moondial at Queens' College, Cambridge, showing the table of corrections for the phase of the moon

Moondials are time pieces similar to sundials. The most basic moondial is accurate only on the night of the full moon. Every night after that, it loses on average [a] 48 minutes, while every night preceding the full moon it gains 48 minutes. Thus, one week to either side of the full moon, the moondial will read 5 hours and 36 minutes before or after the correct time. [ citation needed ]

Contents

More advanced moondials include charts showing the exact calculations to find the correct time, as well as dials designed with latitude and longitude.

Moondials are very closely associated with lunar gardening (night-blooming plants), and some comprehensive gardening books mention them.

See also

Notes

  1. The Moon's orbit is not circular, so it does not move around the Earth at a uniform rate. Thus while the average difference between moonrises is 48 minutes, the actual time can vary considerably (roughly 20min to 1hr50min depending on the time of year and the location of the Moon in its orbit). The time read by a moondial will also vary in a similar, though not so drastic manner.

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<span class="mw-page-title-main">Full moon</span> Lunar phase: completely illuminated disc

The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon. This means that the lunar hemisphere facing Earth—the near side—is completely sunlit and appears as an approximately circular disk. The full moon occurs roughly once a month.

<span class="mw-page-title-main">Lunar eclipse</span> Natural phenomenon wherein the Earth casts a shadow on the Moon

A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. Such an alignment occurs during an eclipse season, approximately every six months, during the full moon phase, when the Moon's orbital plane is closest to the plane of the Earth's orbit.

<span class="mw-page-title-main">Lunar phase</span> Shape of the Moons sunlit portion as viewed from Earth

A lunar phase or Moon phase is the apparent shape of the Moon's directly sunlit portion as viewed from the Earth. Because the Moon is tidally locked with the Earth, the same hemisphere is always facing the Earth. In common usage, the four major phases are the new moon, the first quarter, the full moon and the last quarter; the four minor phases are waxing crescent, waxing gibbous, waning gibbous, and waning crescent. A lunar month is the time between successive recurrences of the same phase: due to the eccentricity of the Moon's orbit, this duration is not perfectly constant but averages about 29.5 days.

<span class="mw-page-title-main">Eclipse cycle</span> Calculation and prediction of eclipses

Eclipses may occur repeatedly, separated by certain intervals of time: these intervals are called eclipse cycles. The series of eclipses separated by a repeat of one of these intervals is called an eclipse series.

<span class="mw-page-title-main">March 2026 lunar eclipse</span> Total lunar eclipse of 2 March 2026

A total lunar eclipse will occur at the Moon’s descending node of orbit on Tuesday, March 3, 2026, with an umbral magnitude of 1.1526. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. The Moon's apparent diameter will be near the average diameter because it will occur 6.7 days after perigee and 6.9 days before apogee.

<span class="mw-page-title-main">July 2000 lunar eclipse</span> Central lunar eclipse

A total lunar eclipse occurred at the Moon’s descending node of orbit on Sunday, July 16, 2000, with an umbral magnitude of 1.7684. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 1.1 days after apogee, the Moon's apparent diameter was smaller.

<span class="mw-page-title-main">March 1997 lunar eclipse</span> Partial lunar eclipse March 24, 1997

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<span class="mw-page-title-main">June 2029 lunar eclipse</span> Future lunar eclipse

A total lunar eclipse will occur at the Moon’s ascending node of orbit on Tuesday, June 26, 2029, with an umbral magnitude of 1.8452. It will be a central lunar eclipse, in which part of the Moon will pass through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 3.7 days before perigee, the Moon's apparent diameter will be larger.

<span class="mw-page-title-main">July 1982 lunar eclipse</span> Total lunar eclipse 6 July 1982

A total lunar eclipse occurred at the Moon’s descending node of orbit on Tuesday, July 6, 1982, with an umbral magnitude of 1.7180. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 1.2 days after apogee, the Moon's apparent diameter was smaller.

<span class="mw-page-title-main">August 1971 lunar eclipse</span> Total lunar eclipse August 6, 1971

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Friday, August 6, 1971, with an umbral magnitude of 1.7283. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 2.3 days before perigee, the Moon's apparent diameter was larger.

<span class="mw-page-title-main">April 1968 lunar eclipse</span> Total lunar eclipse on April 13, 1968

A total lunar eclipse occurred at the Moon’s descending node of orbit on Saturday, April 13, 1968, with an umbral magnitude of 1.1116. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 1.1 days before perigee, the Moon's apparent diameter was larger.

<span class="mw-page-title-main">July 1953 lunar eclipse</span> Total lunar eclipse July 26, 1953

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Sunday, July 26, 1953, with an umbral magnitude of 1.8629. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 2.1 days before perigee, the Moon's apparent diameter was larger.

<span class="mw-page-title-main">September 1913 lunar eclipse</span> Central lunar eclipse in the 1910s

A total lunar eclipse occurred at the Moon’s ascending node of orbit on Monday, September 15, 1913, with an umbral magnitude of 1.4304. It was a central lunar eclipse, in which part of the Moon passed through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring only about 30 minutes after apogee, the Moon's apparent diameter was smaller.

<span class="mw-page-title-main">May 2087 lunar eclipse</span> Astronomical event

A total lunar eclipse will occur at the Moon’s ascending node of orbit on Saturday, May 17, 2087, with an umbral magnitude of 1.4568. It will be a central lunar eclipse, in which part of the Moon will pass through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 2 days after apogee, the Moon's apparent diameter will be smaller.

<span class="mw-page-title-main">May 1910 lunar eclipse</span> Total lunar eclipse in 1910

A total lunar eclipse occurred at the Moon’s descending node of orbit on Tuesday, May 24, 1910, with an umbral magnitude of 1.0950. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 2.4 days after apogee, the Moon's apparent diameter was smaller.

<span class="mw-page-title-main">February 2055 lunar eclipse</span> Astronomical event

A total lunar eclipse will occur at the Moon’s ascending node of orbit on Thursday, February 11, 2055, with an umbral magnitude of 1.2258. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring only about 15 hours before perigee, the Moon's apparent diameter will be larger.

<span class="mw-page-title-main">January 2084 lunar eclipse</span>

A total lunar eclipse will occur at the Moon’s descending node of orbit on Saturday, January 22, 2084, with an umbral magnitude of 1.1531. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 4 days after apogee, the Moon's apparent diameter will be smaller.

<span class="mw-page-title-main">May 2069 lunar eclipse</span> Central lunar eclipse

A total lunar eclipse will occur at the Moon’s ascending node of orbit on Monday, May 6, 2069, with an umbral magnitude of 1.3242. It will be a central lunar eclipse, in which part of the Moon will pass through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 2.3 days after apogee, the Moon's apparent diameter will be smaller.

<span class="mw-page-title-main">Lunar month</span> Time between successive new moons

In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month.

References