Solar eclipse of June 8, 1918

Solar eclipse of June 8, 1918
Solar eclipse of June 8, 1918
	Map
Type of eclipse
Nature	Total
Gamma	0.4658
Magnitude	1.0292
Maximum eclipse
Duration	143 s (2 min 23 s)
Coordinates	50°54′N 152°00′W / 50.9°N 152°W
Max. width of band	112 km (70 mi)
Times (UTC)
Greatest eclipse	22:07:43
References
Saros	126 (42 of 72)
Catalog # (SE5000)	9324

A total solar eclipse occurred on June 8, 1918. The eclipse was observed by a U.S. Naval Observatory team at Baker City in Oregon. The painting below shows totality when the moon prevented the sun's rays from hitting that part of Oregon. The track of the eclipse went across the United States.

The path

1918 Solar eclipse painting by Howard Russell Butler

The path of the eclipse started south of Japan, went across the Pacific Ocean, and then across the United States. The largest city to see totality was Denver although many could theoretically see it as the size of the shadow was between 70 and 44 miles (113 and 71 km) across as it travelled across America. The longest duration of totality was in the Pacific at a point south of Alaska. The path of the eclipse finished near Bermuda.^[1]

U.S. Observation team

Aerial view of Baker City, Oregon in 1918.

The path clipped Washington State and then moved across the whole of Oregon and then the rest of the country exiting over Florida. The U.S. Naval Observatory obtained a special grant of $3,500 from Congress for a team to observe the eclipse in Baker City in Oregon. The team had been making preparations since the year before and John C. Hammond led the first members to Baker City on April 11th.^[2] The location was important as it influenced the probability of cloud cover and the duration and angle of the sun during the eclipse. The team included Samuel Alfred Mitchell as its expert on eclipses, and Howard Russell Butler, an artist and physicist. In a time before reliable colour photography, Butler's role was to paint the eclipse at totality after observing it for 112.1 seconds.^[3] He noted later that he used a system of taking notes of the colours using skills he had learnt for transient effects.^[3]

Joel Stebbins and Jakob Kunz from the University of Illinois Observatory made the first photoelectric photometric observations of the solar corona from their observing site near Rock Springs, Wyoming ^[4]

Observation

As the time came for totality the team watched as clouds obscured the sun. The clouds did clear but during their most important observations the sun was covered by a thin cloud. The sun was completely visible five minutes later.^[2] This was not unusual as cloudy conditions were reported across the country where the eclipse was also observed from the Yerkes Observatory, Lick Observatory and Mount Wilson Observatory.^[5]

Related eclipses

There were two other eclipses that year. The first was a partial lunar eclipse, during which the shadow of the earth can be seen on the moon, and another solar eclipse that took place on December 3 over South America.^[1] The other solar eclipse however was an annular eclipse which occurs when the moon has a smaller apparent diameter and therefore never fully obscures the sun.

Solar eclipses of 1916–1920

This eclipse is a member of a semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.^[6]

The solar eclipses on February 3, 1916 (total), July 30, 1916 (annular), January 23, 1917 (partial), and July 19, 1917 (partial) occur in the previous lunar year eclipse set.

Solar eclipse series sets from 1916 to 1920
Ascending node			Descending node
Saros	Map	Gamma	Saros	Map	Gamma
111	December 24, 1916 Partial	−1.5321	116	June 19, 1917 Partial	1.2857
121	December 14, 1917 Annular	−0.9157	126	June 8, 1918 Total	0.4658
131	December 3, 1918 Annular	−0.2387	136 Totality in Príncipe	May 29, 1919 Total	−0.2955
141	November 22, 1919 Annular	0.4549	146	May 18, 1920 Partial	−1.0239
151	November 10, 1920 Partial	1.1287

Notes

^ ^a ^b Motherwell, R.M. (1918). "The Total Solar Eclipse, June 8, 1918". Journal of the Royal Astronomical Society of Canada. 12: 160–168A. Bibcode:1918JRASC..12..160M.
^ ^a ^b Hammond, J.C. (1919). "The Naval Observatory eclipse expedition, June 8, 1918". Popular Astronomy. 27 (1): 1. Bibcode:1919PA.....27....1H.
^ ^a ^b Lawrence, Jenny; Richard Milner (February 2000). "A Forgotten Cosmic Designer". Natural History. Retrieved 19 October 2010.
^ Stebbins, Joel (1918). "The Illinois eclipse expedition to Rock Springs Wyoming". Popular Astronomy. 26. Bibcode:1918PA.....26..665S.
^ "Total Solar Eclipse of June 8, 1918". Nature. 102 (2553): 89–90. 3 October 1918. Bibcode:1918Natur.102...89.. doi:10.1038/102089a0.
^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.