From U. S. Coast and Geodetic Survey Annual Report, 1882, p. 463-470:
THE TOTAL SOLAR ECLIPSE OF JANUARY 11, 1880,
OBSERVED AT MOUNT SANTA LUCIA, CALIFORNIA
By George Davidson, Assistant, U. S. Coast and Geodetic Survey
San Francisco, Cal., January 16, 1880
Dear Sir: After computing the central line of totality of the solar eclipse of
January 11, I decided to occupy the triangulation station of the Coast and
Geodetic Survey, Mount Santa Lucia, about 5,700 feet elevation in latitude.
36º 08’ 20" north and longitude 121º 24’ 30’ west of Greenwich, and lying 35
miles southeast from Point Pinos. This station is only 12 or 15 miles from
the coast line, but is separated from the mountains immediately overlooking
the shore by
the deep, narrow valley of the San Antonio, which flows southward to join the
flowing northward. There is another mountain on the Coast Range, lying near
the path of the central totality, about 10 miles farther to the westward and
5,000 feet elevation, but its well-nigh inaccessible. On the triangulation
reconnaissance it is known as Cone Peak.
Although the ascent of Santa Lucia Mountain is somewhat difficult I was very
well satisfied with the selection and the advantages which it afforded.
In this work the party consisted of Assistants Gilbert and Colonna,
Subassistant Dickins, myself, my son, and four hands. Our outfit was of the
simplest character, although we expected snow and heavy weather at that
elevation and season.
The instruments were:
- Equatorial 6 7/16 inches (with star spectroscope), portable observatory,
canvas dome (George Davidson).
- Hassler equatorial, 3 inches, United States Coast and Geodetic Survey.
- Zenith telescope No. 1, 2 7/8 inches, United States Coast and Geodetic Survey.
- Meridian instrument No. 1, 2 7/8 inches, canvas observatory, United States
Coast and Geodetic Survey.
- Reconnoitering telescope No. 24, 2½ inches, United States Coast and Geodetic
- With chronometers, sextant, barometers, thermometers, solar-radiation
Professor Frisby, from the United States Naval Observatory, asked my advice in
San Francisco about the best location, facilities, &c. I freely gave him all
the information I had, and as his funds were very low, and he had no camp
outfit whatever, I invited him to occupy the same station and promised that we
would carry his instruments, &c., with ours, he bearing a proportion of the
general expense. He accepted the proposition.
The Southern Pacific Railroad, through Mr. Bassett, ordered every facility to
be granted my party in the transportation of the instruments, &c.
Through the active kindness of H. M. Newhall, esq., of San Francisco, I was
enabled to obtain transportation by teams and animals and the services of his
majordomo, Mr. Fancher, to move from Jolon to the base of Santa Lucia.
Mr. Colonna, with Professor Frisby, examined the approaches to the mountain,
and after a second examination by Mr. Colonna the best available trail was
chosen. It is very steep and rough, and the total rise is about 4,000 feet in
three or four miles. When the station is occupied for the triangulation the
trail can be zigzagged in some of the steepest rocky places. At Camp Milpitas
(latitude by sextant 36º 05’ 54") which the wagons reached, we kept the pack
animals, on account of the severity of the weather and the necessity of
getting fodder from Jolon.
The summit of Santa Lucia is in two peaks, about 200 yards apart, with a
saddle or depression of 20 feet between them. The eastern one will doubtless
be chosen for the triangulation; we chose the western one for the eclipse work
as affording us protection for the tents and a nearby supply of fire-wood.
Mr. Gilbert secured the base for the large equatorial, and assisted in
Mr. Colonna with Mr. Dickins prepared the block and observing tent for the
meridian instrument which was used for transit observations and for latitude.
With the sextant I observed for latitude, but the heavy weather came upon us
before the instruments were fairly mounted; fierce winds, rain, sleet, and
snow making everything very uncomfortable. The temperature was mostly below
freezing and upon one night, when Mr. Colonna was observing, the thermometer
recorded 11½º, with a bitter north wind blowing. When we first reached the
mountain the earth was frozen to a depth of 6 inches, which increased before
we left. But the weather cleared up on the afternoon of the 10th, and Sunday
(the 11th) opened clear and cold, with the temperature at 15º and a stiff
north wind. To this time Mr. Colonna had determined the errors of the
chronometers by transit observations, and also the latitude by two nights’
observations upon seven pairs of stars. When opportunity afforded, I had
observed for time and latitude with the sextant.
To check the longitude of the mountain as given on the reconnaissance plan,
Mr. Dickins made a round of horizontal angles upon all known points.
The view from Santa Lucia is uninterrupted: Point Arguello is distinctly
visible at 90
geographical miles distant. To the west the ocean is visible except where
obstructed by the summit of Cone Peak.
I could have selected a point in the Salinas Valley on the line of totality,
but I was afraid of the valley fogs, of which there were several on days when
the mountains were clear.
My plan of operations was to observe the beginning and ending of the eclipse,
the beginning and ending of totality; but the latter by only one or two
observers, whilst the rest sketched the corona and looked out for
intramercurial planets. By rising to this elevation I had computed that the
ending of the eclipse would be visible.
I had interested parties in the Salinas and San Antonio Valleys to note
whether the eclipse was total at Soledad on the northern limit, and have
verbal reports and expect others.
Of course I determined to look for intramercurial planets, and had five star
charts prepared for the purpose, one for each observer who studied the
relative position of the probably visible stars. The equatorial zenith
telescope and meridian instrument would have given absolute positions, had
such objects been detected.
Diagrams were prepared upon which to sketch the corona, rose-colored flames,
As the computed time of totality was only 331/2 seconds, the chances for our
doing much in either of the last two schemes were infinitely small;
nevertheless I felt sure of doing something trustworthy.
The observers were as follows:
I had taken with me two chronometers; obtained the use of a third from
Professor Frisby; used pocket chronometer Widenham 900, and a watch. All were
compared by Mr. Colonna before, during, and after the eclipse.
- Assistant Davidson: 6 7/16 inch equatorial. Power estimated 300; colored
glasses show sun greenish yellow; Herschel prism; solar eye-piece.
- Assistant Gilbert: United States Coast Survey Hassler equatorial, 3 inches.
This is the instrument with which I observed the solar total eclipse of August
7, 1869, in Alaska. Direct eye-piece, power about 100; colored glass, neutral
- Assistant Colonna: United States Coast Survey meridian instrument No. 1 turned
out of the meridian. Objective 2 7/8 inches; direct eye-piece with prism,
power 60; colored glass shows sun red.
- Subassistant Dickins: United States Coast Survey zenith telescope No. 1.
Objective 2 7/8 inches; direct eye-piece with prism, power 85; colored glass
shows sun greenish orange.
- George F. Davidson: United States Coast Survey reconnoitering telescope No.
24. Objective 2 9/16; direct eye-piece, power about 40, showing whole sun in
the field; colored glasses show sun greenish orange.
Mr. Colonna had good transit observations, and a good determination of the
latitude which I had, by sextant observations, placed in 36º 08’ 20", and from
the reconnaissance sheet in 121º 24’ 30".
Sunday, January 11. The morning was remarkably clear and the atmosphere very
steady, with a cold and moderately strong wind from the north. Temperature
l5º. No clouds were visible except a low bank about half a degree higher on
the western horizon. The instruments were all in position on the western side
of the summit, and protected from the wind to prevent vibration.
As the time of first contact approached I gave warnings at 5, 4, 3, and 2
minutes before the
computed time. Each observer watched to see if he could perceive the moon's
disk before it touched the sun; but it was not seen.
The limb of the sun was not absolutely steady, but nearly so, and sharply
defined. The three clusters of spots were well made out in all the
telescopes, although some of the individual spots were very minute; the
penumbrae were well marked and defined; the mottled appearance as of rice
grains was visible over the whole disk, and the faculae readily traced in all
their irregularities. There was no spurious disk such as arises from great
atmospheric disturbance, but there was just enough atmospheric tremor to give
an occasional shivering to the border. There was no disturbance of the limb
at the point of first contact.
I was using a Herschel prism solar eye-piece that permitted most of the heat
and light rays to pass directly through the eye-tube, whilst the eye-piece was
at right angles to the optical axis. The position circle was not constructed
to fit this solar eye-piece, and therefore I had to estimate the position on
the sun's limb where the moon would first appear. I saw the first indentation
when it was about the apparent thickness of a coarse spider thread in the eye-
piece, and noted the time, which was, I think, before that of anybody else.
As the moon advanced I noticed the time of disappearance of the umbrae in each
of the groups of spots. These were also observed by the others.
As the moon's disk advanced with a well-defined outline apparently broken by
lunar mountains, the sun’s cusps were very sharp and clear, but whenever a
tremor occurred on account of any slight atmospheric disturbance these cusps
where apparently doubled. This phenomenon was also observed and recorded by
Mr. Colonna. It was not owing to want of parallelism of the colored glasses,
for when the atmosphere steadied the cusps were single, sharp points. Had the
atmosphere been much more disturbed the points of the cusps would have
and blunted, as Assistant Rodgers observed them at Oakland. This duplication
of the cusp is shown on an exaggerated scale in Fig. 1.
During the progress towards totality I called the observer's attention to the
fact that there was a perceptible difference in the darkness of the sky
adjacent to the sun's disk yet unobscured, at A, compared with that
immediately adjacent and still covered by the moon's advancing disk, which
projected beyond the sun's disk at B. And yet none of us had been able to
detect the moon's disk before it touched the border of the sun.
At 50 minutes after commencement I noted the "sun much steadier, cusps sharp
as knife point, limb of moon sharp."
At one hour after commencement "the limb of the moon steady enough to see the
lunar mountains near apparent right cusp" (C), which I was then examining
The irregularities of the lunar outline could be detected wherever an
examination was made, the more clearly when no shiverings or tremors affected
Towards totality a few cirrus clouds formed on the line to the sun and the
atmospheric disturbances were at times increased. As totality rapidly
approached the crescent of sunlight was remarkably long and narrow on account
of the slight difference of the apparent diameters of the two disks. To
illustrate this I have made the accompanying sketch (Fig. 3) to reduced scale,
exhibiting the shape of the crescent at 3 minutes 30 seconds before totality,
and at 12 or 13 seconds before the total phase commenced. At the bottom I
have exhibited the moon’s disk when projected upon the sun about ten seconds
after the commencement of the eclipse. The last line of sunlight was from 30º
to 40º in length before it broke. But this long, narrow crescent
exhibited no distortion from atmospheric disturbances, and no wavy movement,
occasionlly, that slight tremor which I have designated as "shivering," and
which is seen at times, in geodetic observations. The cusps, before the
crescent was reduced to a line, were remarkably sharp and curved points, as if
cut by the finest graver. The breaking of this last line of sunlight was
occasioned by the intrusion of the lunar mountains and inequalities; and it
presented the appearance of a line of dots, dashes, and spaces. There was no
wavy motion to interfere with this exhibition; whenever a bright spot or dash
disappeared it was gone for good.
As in my observations upon similar phenomena in the eclipse of August 7, 1869,
atmospheric conditions were so favorable for steadiness of image that the
"Bailey’s-beads" were totally and wholly wanting.
I did not remove the colored glass in observing this contact, as I had done in
1869, because I wished to preserve my eyes for any possible intra-mercurial
planet. But immediately upon leaving the telescope I saw that, on account of
the small diameter of the cone of shade the brightness of the corona, and
probably the effect of the light cirrus cloud, the illumined atmosphere
rendered the sky too bright to see any stars or small planets, and I fixed in
my mind the position and size of the rose-colored flames and especially the
first circle of bright light around the sun, whilst others sketched the
outline of the corona (Fig. 4).
There was a brilliant rose-colored flame just at the left of the sun's vertex;
and the lower part of the moon's disk-say, one-third of the circumference was
apparently bordered by a remarkably brilliant and continuous line of rose-
colored flames. The upper flame was between the one-tenth and one-twelfth of
the sun's diameter in height; and the lower border of flame was about the one
eighth or one twentieth, of the sun's diameter in height.
The first concentric ring of white light around the sun was strikingly bright
and extended one-tenth of the diameter beyond the disk. Mr. Dickins noted
this and also a second but fainter concentric ring. The corona had the
general form of a parallelogram with the angles prolonged in the direction of
the longer sides, and stretched at an angle of about 35º with the vertical,
from the upper left to the lower right. The accompanying sketch is a near
copy of the sketch which
Mr. Colonna and myself made immediately after totality; the parts drawn by Mr.
Colonna marked with a C; those by myself with a D. The parts marked (a) were
much lighter than the other parts of the corona. The outline and general
features of the corona are quite consistent among the observers, whilst that
of Dr. Gustav Eisen, near Fresno, is equally consistent. In addition to the
originals I shall endeavor to have prepared a specially colored sketch.
Two of the observers, Messrs. Colonna and Dickins, distinctly saw the changing
appearance of the corona at its most extended points, which seemed to contract
and lengthen rapidly; a phenomenon similar to what I observed in the comet of
Messrs. Gilbert and Colonna observed the time of the third contact, although
not with confidence.
Before totality we all saw the shadow of the total phase coming over the ocean
as a brown area on the surface. After totality I saw the shade of the
retreating cone against the eastern sky, but could not see the shadow upon the
distant mountains, which were too dark. This shadow had not the density and
impressiveness of the shadow coming down the valley of the Chilkaht, Alaska,
where it was visible on the flanks of the mountains and against the snow
After totality the sun was for some time behind a cirro-stratus cloud, and the
steadiness of the atmosphere was disturbed. The disk of the sun only came
from under this cloud a few minutes before the fourth contact, whilst below
the sun lay the cloud bank, which had hung on the
horizon all day. This cloud was 35’ above the horizon. Here the atmosphere
was in a remarkable state of undulation, and the limbs of the sun and moon
moving in great rapid waves, so that it was next to impossible to note in the
smaller telescopes precisely when the moon left the Sun. I observed it with
no satisfaction, except that the time noted was approximately close. The sun
set about ten minutes after the last contact.
The following preliminary tabulation will give an idea of the times observed
by the different observers. Tile corrections to the different time-pieces are
very close to the truth, but no rigorous reduction has been made.
Equal weight cannot be given to Davidson, jr., as he has not had much
experience as an observer.
Incidentally, observations were made for the temperature during the eclipse,
but not at regular intervals.
The following are the results, premising that the temperature was 15º at
sunrise, with a moderately strong north wind. The wind continued all day, but
with decreasing force.
Jupiter and Mars were seen by the observers several minutes before totality.
No stars were seen by any observer.
At Soledad and at Oak Grove the sun was visible at the greatest obscuration;
but Señor Villegas informed me that where he was, about 1½ or 2 miles' south
of Soledad, there was a point of the sun about as bright as Venus, visible
about 30º or 40º to the right of the vertex. At Oak Grove, about l¼ miles
south of Soledad, there was a slight line of the sun visible. On the southern
limit, at Lowe's stage station, the sun was visible, and at Jolon a very thin
line of the sun was visible. I have written to get nearer limits for the
southern line of totality. At Fresno, I interested Dr. Gustav Eisen to go to
the line of totality where it crosses the Southern Pacific Railroad; and Dr.
W. H. Harkness, of the California Academy of Sciences, reports that he went
with the party to Sycamore and witnessed the phenomena. The phase of totality
was not visible at Fresno on the southern side.
I extract the following description from Dr. Eisen's letter to me:
The totality was not seen at Fresno; but following your advice I had gone to
Borden, a station on the Southern Pacific Railroad about 10 miles north of
Fresno. The totality here lasted exactly 31 seconds, and I suppose I was
pretty near the central path of the shadow.
Dr. Harkness informed me that the shadow was very distinct because the Sierra
was covered with snow, and that it passed like the shadow of a cloud.
Shortly before totality I suddenly saw the western edge of the moon's surface
lighted up by a reddish light, displaying the convex and mountainous surface
in a most extraordinary manner. This vanished, however, at totality. The
atmosphere seemed perfectly quiet, and no disturbance or tremor of the limbs
was visible. At totality the sky around the sun was entirely free from
clouds, but so lighted up by the corona, or by something else, that there
seemed little prospect of seeing any intra-mercurial planet. The appearance
of totality was, to use the faintest language, grand.
I had my paper prepared according to your instructions and made a rapid
sketch which I enclose herewith. The second accompanying drawing was made
after my return home. The red, rosy, and purple flames around the lower left
border of the moon, covered, at the beginning of totality, about one-fourth or
one-fifth of the border, but increased rapidly, and at the end of totality
they covered about one-third of the moon's circumference. Just at the apex I
saw an immense pyramidal flame of yellow, very brilliant light, and also a
much smaller one at the right horizontal edge, also of brilliant white or
yellow light. (Fig. 5, without color.)
The corona of radiated white, pale light extended from the upper left side to
the lower right. The extremities of the corona I could follow to about one
diameter distance from the sun. Judging from the shadow of the moon, which we
saw passing over the Sierra, the diameter of the cone could not have been much
more than ten miles.
I. P. Moore, esq. (vice-president of the California Academy of Sciences),
observing the eclipse at San Rafael, reports that at commencement he saw
iridescent colors at the part of the sun first touched by the moon, but that
they immediately disappeared.
As a spectacle, this eclipse in some respects exceeded, and in others was
inferior to, that which I observed August 7, 1869, in Alaska. Here the rose-
colored flames and inner circle of white light were perfectly glorious, and
the corona was more brilliant, but the disk of the moon did not
stand out with that blackness and perspective effect which I saw on the
Chillkaht. This might be
in part the result of interference by the cirrus clouds. The sky here was
much brighter on account of the closeness of the apparent diameters of the sun
and moon. The shadow on the ocean was a poorly defined brown area; in the
valley of the Chilkaht the coming of the shadow on the mountain flanks and
over the snow -gorges was more distinct. Near Fresno and at Millerton the
shadow was seen coming over the San Joaquin plains, and after totality the
shadow was very beautifully distinct on the snow-covered flanks of the Sierra
This eclipse affords another confirmation of the theory which I have before
reported, that the exhibition of "Baily's Beads," the "ligament" and "black
drop" in transits of Mercury and Venus, the projection of a colored star on
the moon's bright limb at occultation, and similar phenomena, are the
consequences of atmospheric disturbances occasioned by irregularities of
refraction, etc., which create spurious disks of the sun, moon, and planets.
This view, when first insisted upon, was strongly controverted, but we have
analogous phenomena exhibited almost every day in the geodetic observations of
the Survey. At high isolated elevations, and during a remarkably steady
atmosphere, whether dry or moist, at any elevation, all these abnormal
I may mention here, that whilst at this station the zodiacal light was
observed every evening when the weather was clear. It was distinctly marked,
and stretched up to an elevation from 4º to 6º higher than Jupiter, and from
4º to 5º to the right. The base, at 6½ or 7 p.m., was about l2º broad, and
the inclination 10º from the vertical to the left.
I enclose special reports of Assistants Gilbert and Colonna and Subassistant
Dickins, with their sketches; also second sketch of Dr. Eisen (Fig. 5).
The original records for time, latitude, and the epochs of commencement, etc.,
together with the original sketches, will be duly transmitted.
Assistant-Coast and Geodetic Survey.
Carlile P. Patterson,
Superintendent Coast and Geodetic Survey.
January 29, 1880.
P. S. -Assistant Colonna has reduced two pairs of the latitude stars, which
give the latitude of the station 36º 08’ 40", and I have graphically located
the station from Mr. Dickins's horizontal directions and Mr. Eimbeck's
positions on his reconnaissance plan of 1873. This gives for the longitude
121º 23’ 40", to which must be added 1’ 02" for determination by telegraph
longitudes, so that we may provisionally place Station Santa Lucia in latitude
36º 08’ 40"; longitude 121º 24’ 40".
A closer approximation to the longitude could doubtless be made by computing
the triangles of the reconnaissance from Mr. Eimbeck's measures.