Solar eclipse of December 14, 1955

{{Infobox solar eclipse|1955Dec14

| previous = Solar eclipse of June 20, 1955

| next = Solar eclipse of June 8, 1956

}}

An annular solar eclipse occurred at the Moon's ascending node of orbit on Wednesday, December 14, 1955,{{cite web|title=December 14, 1955 Annular Solar Eclipse|url=https://www.timeanddate.com/eclipse/solar/1955-december-14|publisher=timeanddate|access-date=5 August 2024}} with a magnitude of 0.9176. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Occurring about 1 day before apogee (on December 15, 1955, at 7:10 UTC), the Moon's apparent diameter was smaller.{{cite web|title=Moon Distances for London, United Kingdom, England|url=https://www.timeanddate.com/astronomy/moon/distance.html?year=1954&n=136|publisher=timeanddate|access-date=5 August 2024}}

The duration of annularity at maximum eclipse (closest to but slightly shorter than the longest duration) was 12 minutes, 9.17 seconds in the Indian Ocean. It was the longest annular solar eclipse from December 17, 168 to January 14, 3080. Among all the 23740 solar eclipses from 4000 BC to 6000 AD, 7881 are annular, and only 3 of them are longer than this one.{{cite web|title=Annular Solar Eclipses with Durations Exceeding 11m 00s: -3999 to 6000|url=http://eclipse.gsfc.nasa.gov/SEcatmax/SE-3999-6000MaxA.html|publisher=NASA Eclipse Web Site}} This was the 20th member of Solar Saros 141, and the last of first set of solar eclipses without a penumbral internal contact (without a penumbra northern limit), the next event is the December 24, 1973 event, which is the first of 19 solar eclipses with a penumbral internal contact (has penumbral northern and southern limits) until 2298 Jul 09.

Annularity was visible from French Equatorial Africa (the part now belonging to Chad), Libya, Anglo-Egyptian Sudan (the part now belonging to Sudan) including the capital city Khartoum, French Somaliland (today's Djibouti) including the capital Djibouti City, British Somaliland (today's Somaliland) including the capital city Hargeisa, the Trust Territory of Somaliland (today's Somalia), the Maldives, Andaman and Nicobar Islands, Burma, Thailand including the capital city Bangkok, Cambodia, Laos, North Vietnam and South Vietnam (now belonging to Vietnam), China, British Hong Kong, Taiwan (including the Pratas Islands), and Ryukyu Islands. A partial eclipse was visible for parts of East Africa and Asia.

This was the third of four central solar eclipses visible from Bangkok from 1948 to 1958, where it is extremely rare for a large city to witness four central solar eclipses within 10 years.

Extreme duration

With a maximum length of annularity duration of 12 minutes and 9.17 seconds, this is the longest solar eclipse in the millennium, as well as the longest duration in Saros 141 and one of the longest eclipses ever observed. The annular path begins in northern Africa, then passing Maldives (near the maximum eclipse), then crosses just southern edge of Sri Lanka, then the track continues to some countries in Indochina and the track ends just slightly after the track passes Taiwan.

Observation

A joint team of the Georgetown University Astronomical Observatory, Washington, D.C. and the United States Air Force observed the annular eclipse in multiple locations around the world. Among them, in Khartoum, capital of Anglo-Egyptian Sudan, the partial phase started before sunrise, and the annular phase was shortly after sunrise. The team measured the refraction with the zenith distance between 80° and 90°.{{cite web|title=MEASUREMENTS OF THE SUN'S LIMB FOR THE DETERMINATION OF REFRACTION BETWEEN 80 DEGREES AND 90 DEGREES ZENITH DISTANCE|work=GEORGETOWN COLL WASHINGTON D C OBSERVATORY|author=DE KORT, JULES|url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0250928|date=30 September 1960|archive-url=https://web.archive.org/web/20160428030745/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0250928|archive-date=28 April 2016}}

Eclipse details

Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.{{cite web|title=Annular Solar Eclipse of 1955 Dec 14|url=https://eclipsewise.com/solar/SEprime/1901-2000/SE1955Dec14Aprime.html|publisher=EclipseWise.com|access-date=5 August 2024}}

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|+December 14, 1955 Solar Eclipse Times

! Event

! Time (UTC)

First Penumbral External Contact

| 1955 December 14 at 04:01:44.4 UTC

First Umbral External Contact

| 1955 December 14 at 05:10:54.4 UTC

First Central Line

| 1955 December 14 at 05:14:41.0 UTC

First Umbral Internal Contact

| 1955 December 14 at 05:18:29.1 UTC

Greatest Duration

| 1955 December 14 at 07:01:01.9 UTC

Greatest Eclipse

| 1955 December 14 at 07:02:25.1 UTC

Equatorial Conjunction

| 1955 December 14 at 07:04:18.1 UTC

Ecliptic Conjunction

| 1955 December 14 at 07:07:33.8 UTC

Last Umbral Internal Contact

| 1955 December 14 at 08:46:19.4 UTC

Last Central Line

| 1955 December 14 at 08:50:08.2 UTC

Last Umbral External Contact

| 1955 December 14 at 08:53:55.4 UTC

Last Penumbral External Contact

| 1955 December 14 at 10:03:06.4 UTC

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|+December 14, 1955 Solar Eclipse Parameters

! Parameter

! Value

Eclipse Magnitude

| 0.91764

Eclipse Obscuration

| 0.84206

Gamma

| 0.42658

Sun Right Ascension

| 17h23m01.9s

Sun Declination

| -23°10'20.1"

Sun Semi-Diameter

| 16'14.9"

Sun Equatorial Horizontal Parallax

| 08.9"

Moon Right Ascension

| 17h22m58.2s

Moon Declination

| -22°47'23.2"

Moon Semi-Diameter

| 14'42.5"

Moon Equatorial Horizontal Parallax

| 0°53'59.0"

ΔT

| 31.3 s

Eclipse season

This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.

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|+ Eclipse season of November–December 1955

! November 29
Descending node (full moon)

December 14
Ascending node (new moon)

200px

align=center

| Partial lunar eclipse
Lunar Saros 115

Annular solar eclipse
Solar Saros 141