A partial lunar eclipse occurred at the Moon's ascending node of orbit on Saturday, July 15, 1916, with an umbral magnitude of 0.7944. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. 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. Occurring only about 3.5 hours after perigee (on July 15, 1916, at 1:15 UTC), the Moon's apparent diameter was larger.
Observations The Ross Sea party was a component of Sir Ernest Shackleton's Imperial Trans-Antarctic Expedition of 1914–17. Five men were stranded not far away from Cape Evans. There was sea ice between them and the relative safety of the hut on Cape Evans. On May 8 two of the men, Aeneas Mackintosh and Victor Hayward, decided to make an attempt to reach the hut. Soon after they set out, a blizzard hit. When the weather cleared up, the remaining men tried to look for them, but realized that the ice was far too thin to cross, and that their friends had been lost. Now they knew that they should wait for a thicker ice and for the full moon to attempt the crossing. Having the full moon was essential, because during polar night the moon is the only source of natural light other than the extremely dim light of the stars.
The weather did not cooperate during the full moon of June, but on July 15, everything seemed to be just right: calm weather, thick ice, clear skies and a full moon. The men started their journey in the morning. When the moon rose, however, the men were surprised to find it was about to be eclipsed. Ernest Wild wrote later: Although the eclipse continued for a few hours, the men were fortunate because it was only a partial eclipse. They reached Cape Evans later on the same day.
Visibility The eclipse was completely visible over eastern North America, South America, and Antarctica, seen rising over western North America and the central Pacific Ocean and setting over Africa and western Europe.
Eclipse details Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
+July 15, 1916 Lunar Eclipse Parameters Parameter Value Penumbral Magnitude 1.73508 Umbral Magnitude 0.79437 Gamma −0.59568 Sun Right Ascension 07h36m32.1s Sun Declination +21°35'52.3" Sun Semi-Diameter 15'44.1" Sun Equatorial Horizontal Parallax 08.7" Moon Right Ascension 19h37m12.9s Moon Declination -22°11'11.4" Moon Semi-Diameter 16'43.6" Moon Equatorial Horizontal Parallax 1°01'23.4" ΔT 18.8 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.
+ Eclipse season of July 1916 July 15Ascending node (full moon) July 30Descending node (new moon) Penumbral lunar eclipseLunar Saros 118 Annular solar eclipseSolar Saros 144
Related eclipses Eclipses in 1916 A partial lunar eclipse on January 20. A total solar eclipse on February 3. A partial lunar eclipse on July 15. An annular solar eclipse on July 30. A partial solar eclipse on December 24.
Metonic Preceded by: Lunar eclipse of September 26, 1912 Followed by: Lunar eclipse of May 3, 1920
Tzolkinex Preceded by: Lunar eclipse of June 4, 1909 Followed by: Lunar eclipse of August 26, 1923
Half-Saros Preceded by: Solar eclipse of July 10, 1907 Followed by: Solar eclipse of July 20, 1925
Tritos Preceded by: Lunar eclipse of August 15, 1905 Followed by: Lunar eclipse of June 15, 1927
Lunar Saros 118 Preceded by: Lunar eclipse of July 3, 1898 Followed by: Lunar eclipse of July 26, 1934
Inex Preceded by: Lunar eclipse of August 3, 1887 Followed by: Lunar eclipse of June 25, 1945
Triad Preceded by: Lunar eclipse of September 13, 1829 Followed by: Lunar eclipse of May 16, 2003
Lunar eclipses of 1915–1918 This eclipse is a member of a semester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.
The penumbral lunar eclipses on March 1, 1915 and August 24, 1915 occur in the previous lunar year eclipse set.
Lunar eclipse series sets from 1915 to 1918 Descending node Ascending node Saros DateViewing TypeChart Gamma Saros DateViewing TypeChart Gamma 103 1915 Jan 31Penumbral 1.5450 108 1915 Jul 26Penumbral −1.3553 113 1916 Jan 20Partial 0.9146 118 1916 Jul 15Partial −0.5956 123 1917 Jan 08Total 0.2415 128 1917 Jul 04Total 0.1419 133 1917 Dec 28Total −0.4484 138 1918 Jun 24Partial 0.9397 133 1918 Dec 17Penumbral −1.1035
Saros 118
Tritos series
Inex series
Half-Saros cycle A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros This lunar eclipse is related to two annular solar eclipses of Solar Saros 125. July 10, 1907July 20, 1925
See also List of lunar eclipses List of 20th-century lunar eclipses
Notes
References The Monthly Evening Sky Map, Volumes 9-11 Partial Lunar Eclipse of July 14–15, 1916
External links
https://adsabs.harvard.edu/full/1917PA.....25...71K39.jpg