California's First Observatories.    By Peter Abrahams.

   The first known astronomical instrument that belonged to a Californian, was 
owned by the last Mexican Governor of Alta California, Pio Pico, who occupied that 
office from 1845 to 1846.  He owned a naval telescope by Cutts of London, possibly 
the earliest recorded telescope in California except the spyglasses that came and 
went with explorers and conquistadors.

   The first astronomical observatories in the state of California were more 
precisely geodetic observatories, using astronomical instruments to measure the 
sky, for the purpose of delineating the earth.  In the early 1850s, a series of 
geodetic observatories were established in California by the Coast and Geodetic 
Survey.  These 'astronomical observatories' (as they were called), were permanent 
or temporary in design, and their purpose was to determine latitude and longitude, 
also azimuth bearings between points on the earth; to facilitate map production 
and the setting of boundaries.  In some cases, a secondary purpose concerned the 
science of astronomy.

   The most important person in this history is George Davidson, 1825-1911.  In 
1840, one of the first American observatories was established at Central High 
School in Philadelphia, with Alexander Dallas Bache as director.  Davidson studied 
at the school from 1843 to 1845 & became an assistant to Bache.  He joined the 
U.S. Coast & Geodetic Survey in 1845 and began work in California in 1850, 
establishing positions for headlands on the coastline, probably using a zenith 
telescope and meridian telescope, for the purpose of making accurate coastal 
charts to lower the rate of shipwrecks..  He began at Point Conception, north of 
Santa Barbara, in 1851, and traveled north, surveying at Point Pinos in Monterey, 
the Presidio station in 1852, and further sites, ending after 18 months at the 
Columbia River.
   The California - Nevada border was summarily surveyed as early as 1852, but was 
not precisely determined until George Davidson of the C. & G. S. began work in 
1893.
   Davidson traveled on several eclipse expeditions and other itinerant studies, 
to destinations including Alaska & Japan, typically setting up at the highest 
possible elevation, which in those roadless & motorless days, meant considerable 
labor to the party.  Davidson was delegated to travel to Baja California in 1873, 
to find the site of the Chappe d'Auteroche transit of Venus expedition of 1769, in 
order to establish the exact longitude of the site and the accuracy of their 
measurements, to allow their incorporation into the scientific literature.
   Davidson decided to build an astronomical observatory in San Francisco, 
visiting the hill now known as Lafayette Park in May of 1879, and there building a 
15 foot by 15 foot wooden building with a 10 foot dome.  A 6.4 inch refractor and 
other instruments were paid for by Davidson, and the Survey granted him $120 a 
year for maintenance.  He built a home several hundred feet away circa 1885.  For 
about two decades, while administering many Survey projects covering the West 
coast, Davidson was at the observatory almost every night.  In 1891, he began 15 
months of nightly observations to help determine the variation in latitude.  The 
observatory was one of the standard telegraphic longitude stations of the Pacific 
Coast, and was also made available to neighbors, scientists, students, to whom he 
gave lectures and demonstrations.  After the 1906 earthquake, he removed the 
telescope from its pier and used the observatory as a shelter for the homeless.  
His eyesight had deteriorated since the turn of the century, and circa 1907, this 
forced the closure of the observatory.
   By the late 1860s, Davidson had become convinced that the climate in the 
western U.S. was ideal for astronomy and that the mountains would be an excellent 
observatory site.  He had by then begun working towards the siting of a major 
astronomical observatory in the West by contacting local supporters and gathering 
estimates of the cost, which were roughly 1.5 million dollars.  In 1872, Davidson 
was surveying the northern section of the California - Nevada border.  He made a 
series of observations to test the importance of high altitude to astronomical 
sites, and published two papers in 1872 on 'The Relative Value of Great and Small 
Altitudes for Astronomical Observations'.
   Davidson met James Lick in 1873, frequently returning to discuss astronomy with 
him, who at 80 years had 'never looked through a telescope or read a work on 
astronomy'.  Lick decided to leave his estate to the founding of an observatory, 
whereupon Davidson had to persuade him to site it on a mountain instead of on 
Fourth and Market in San Francisco.  The present site of Lick Observatory is not 
in the upper elevations of the Sierra Nevada favored by Davidson, but then the 
telescope is not the size desired by Lick: 'twice as big' as the largest 
contemporary reflector (which was somehow described as 3 feet in diameter).  It 
required considerable persuasion by Davidson to convince Lick that a 40 inch 
refractor would be massive enough a memorial, after which he visited Alvan Clark, 
who agreed to work 40 inch blanks if Feil of Paris could supply them.   However, 
Lick needed to be persuaded to increase the amount of his bequest, at first to 
$500,000, and finally $700,000., only one half of the estimated cost, at which 
point Davidson withdrew from the project.  However, it was apparently Davidson who 
mentioned the idea that Lick could be interred at the base of the telescope, a 
plan that was carried forth as a provision in Lick's will, 11 years after his 
death.  
   Davidson was the finest field worker in the 19th century U.S. Survey, but in 
1895, his 50th year of service, he & many other employees were dismissed.  He 
began teaching at the University of California; and died in 1911. 
   Davidson was responsible for several improvements to instruments.  The Davidson 
Meridian Instrument, invented in 1867, was extensively used in the Survey for 
determinations of time, latitude, and azimuth.  In 1874, he invented an improved 
clamp to secure astronomic or geodetic instruments.  He also developed a method of 
using a microscope to determine the irregularities in micrometer screws, and a 
sextant with a spirit level attached to help with the function of the horizon.  
These, along with other improvements to instruments, were not patented, Davidson 
stating that he wished them to be freely available to co-workers.

   Victor Killick, in his 'California's First Astronomical Observatories', of 
1958, copied a list of 22 astronomical observatories from a 1900 Coast & Geodetic 
Survey report.  28 such stations were the total reported in C. & G. S. annual 
reports.  The dates referred to the year the station determined its latitude, 
which typically, but not consistently, meant they had been functioning for a short 
period of time: 

1851  Point Conception, Santa Barbara County, source: Killick.
1851  San Diego,  source: Killick.  
1851,  Point Pinos, Monterey County, source: Killick.  
1852  Presidio, San Francisco (old station, later moved to Drill Plain Knoll).  
1853  Bodega.  
1853  Mendocino.  
1853  Pt. Reyes.  
1859  Ross Mountain.  
1859  Sulphur Peak.  
1870  Point Arena.  
1873  Washington Square, San Francisco.  
1876  Mt. Diablo (Killick: in use by 1852).  
1876  Mt. Helena.  
1877  Mare Island Navy Yard, US Navy observatory, source: Killick.  
1879  Mt. Lola, Nevada County (established 1876).  
1879  Round Top, Alpine County (established 1876).  
1880  Monticello.  
1880  Vacca.  
1880  Yolo  N.E. Base.  
1880  Yolo  S.E. Base.  
1882  Mt. Tamalpais.  
1887  Mocho, Santa Clara County (established 1875).  
1888  Lafayette Square, San Francisco.  
1888  Mt. Hamilton.  
1890  Mt. Conness, Tuolumne County (established 1879).  
1897  Ukiah.  

   These observatories would have been equipped with three key instruments.  
First, a horizontal circle consists of a telescope mounted on the radius of a 
circle, so that the angular distance between two objects can be determined, for 
the purpose of triangulation; often a sextant is mounted on a pillar to perform 
this function.  Second, a meridian instrument of a portable type, used to 
determine longitude by noting the time of meridian passage of known stars.  Third, 
a zenith telescope, to determine latitude to a precision beyond what can be 
obtained by sighting Polaris.
   A zenith telescope is an interesting & obscure instrument, basically a 
refractor set to observe overhead and to very precisely measure small angles 
relative to the zenith, between pairs of stars whose position is known with great 
accuracy.  Similar instruments date back to 1669, when Robert Hooke attempted and 
failed to measure solar parallax to observe the earth's motion around the sun.  A 
zenith telescope by George Graham was installed at Kew Observatory in 1725 by 
Samuel Molyneux, for similar & unsuccessful reasons.  The Graham instrument was 
used by James Bradley discover the aberration of starlight in the 1720s.  Bradley 
also measured the nutation of the earth on its axis using a smaller Graham zenith 
telescope.
   John Bird made in 1763 the first zenith telescope brought to America, obtained 
by Thomas Penn for the survey by Mason and Dixon of the Maryland - Pennsylvania 
border.  David Rittenhouse used this instrument in 1769 & 1774, and used it as a 
model to fabricate the first American-made instrument of precision in 1785-6.
   Captain Andrew Talcott of the United States Corps of Engineers improved the 
procedures used for determining latitude in 1834, and his method became standard 
for the United States Coast Survey in 1846.  After leveling the instrument, the 
user selects a pair of stars that can be seen in one field of view, one 
culminating north of the zenith, the other culminating south of the zenith of the 
observer.  The right ascensions of the pair should be close enough that the 
transits occur close in time, but leaving enough time to measure both.  The 
telescope is set to an altitude between the stars, and the bubble level is set to 
mid scale.  The telescope is brought into the plane of the meridian by rotating 
the horizontal circle.  The first star is observed as it crosses vertical cross 
hair, and the horizontal cross hair is then set to split the star.  At that 
setting, the position of the bubble level is recorded using calibrations at each 
end of the bubble.  The telescope is rotated 180 degrees in azimuth, and the 
second star is similarly observed.  Readings from the micrometer are compared and 
corrected by readings from the level.  This method for finding latitude was a very 
valuable improvement in practical astronomy.
   George Davidson preferred a zenith telescope of 3 3/4 inches aperture and 45 
inches focal length, magnifying about 100 power.  Many of these instruments 
designed and made by William Wurdemann of Washington, D.C.

   A precise determination of the longitude of San Francisco  was measured by the 
Coast Survey in 1852, using 51 moon culminations at the Presidio, and 48 moon 
culminations at Telegraph Hill.  (Upper culmination is when the moon reaches its 
highest point in the sky, passing through the line between the zenith and the 
celestial pole.)

   By 1855, an observatory was in use in downtown Sacramento at 56 Fourth Street, 
on the roof of the office of the Surveyor General.  It was used by G.H. Goddard, 
Civil Engineer, and Seneca Hunt Marlette, State Surveyor General, of the State 
Boundary Survey to to assist the location of the eastern boundary of California.  
In the newspaper 'The Democratic State Journal' of Nov. 24, 1855, a visit to the 
observatory is described, noting that Goddard and Marlette "unhesitatingly 
signified their willingness to permit ladies, if accompanied by us, to view the 
planets.  As it would, however, be impossible for us to wait on all our lady 
friends who must be anxious of examining the observatory, we prevailed on these 
gentlemen to do the agreeable in our absence, to all those who use our name as a 
passport.  The ladies, therefore, who visit the observatory, may be assured of 
every attention."

   In 1860, mining engineer & mineralogist George Madeira (October 1836 - January 
1922), built an observatory at his residence in the town of Volcano in Amador 
County, using sheets of cloth as a removeable roof.  A 3 inch Lerebours and 
Secretan telescope on a clock driven equatorial mount was ordered from an 
instrument dealer in San Francisco.  A 'transit' was noted in the observatory; 
this was probably a surveyor's transit belonging to his older brother, who had 
worked as a surveyor and was trained as a civil engineer.
   Madeira had come to California in 1852, carrying a set of celestial charts 
across the plains (and retrieving them after his father had discarded them to 
lighten the wagon load).  Although George's schooling had ceased at 15 years of 
age, his was a serious amateur observatory, where Madeira and Prof. Telerand, a 
minister & mathematician from British Columbia, worked 'day & night', observing 
the sun and the stars.  On June 30, 1861, Madeira discovered a large & bright 
comet, which was in fact already named after the Australian John Tebutt, who had 
found it on May 13.  A report of the observatory, dated 04 March, 1910 is found in 
the Shane archives at Lick.  Madeira's account of sunspot observations was 
published in the Sacramento Daily Union of 18 October 1860, page 1, under the name 
'Herschel, Jr.'.
   Madeira moved to Nevada in 1862, selling his telescope to Josiah Whitney of the 
Geological Survey and discontinuing serious astronomical observation.  He 
purchased a larger telescope circa 1878, to use in a traveling series of lectures 
and public, fee-subsidized observing sessions.  He was a frequent contributor to 
newspapers, including some lessons on astronomy.  He returned to Volcano in 1880 
for a few months, but the walls of the observatory had been dismantled by then, 
and the building was entirely removed circa 1910.  In the late 1990s, the 'Volcano 
Star Party' was held on a nearby site, on Shake Ridge Road, near present day town 
of Volcano, where is located Amador County historic marker / California registered 
landmark No. 715, which reads (mistakenly siting the observatory 2 miles from the 
true location):  "In 1860;  George Madeira built the;  First Amateur Astronomical 
Observatory of Record in California;  On the knoll 365 feet south of this marker.  
Here with a three inch refractor telescope;  he discovered the Great Comet of 
1861.  Erected by Sacramento Valley Astronomical Society;  Stockton Astronomical 
Society;  1958."  Madeira's observatory was the first in California to be devoted 
to the science of astronomy.
   In 1860, James Lick attended one of Madeira's lectures, in San Jose, inviting 
George to his ranch in Santa Clara, where for several nights they observed with 
the three inch telescope and Madeira outlined the history & science of astronomy.  
They met again in 1873, in San Francisco, again observing and visiting; and Lick 
said that Madeira's telescopes were the only such instruments he had ever used.  
Madeira told Lick that if wealth were his, he would construct the largest possible 
telescope, and in a letter to E.S. Holden of Lick from 1887, related his feeling 
that his lessons were crucial to Lick's decision to fund the observatory.

   Circa 1880, Senator Bliss of Los Angeles had an observatory in a tower at his 
home, with a 5 1/4 inch equatorial refractor, later bequeathed to the Southern 
California Academy of Science.  This was on Buena Vista Street, on a hill that has 
since been bulldozed away.
   In 1883, the observatory funded by Anthony Chabot opened in Oakland.
   College of the Pacific followed with an observatory in 1885.
   In Los Angeles, B.R. Baumgardt, F.R.A.S., used a 6 inch Alvan Clark at his home 
on 22nd and Union, in 1893.
   Herbert Martin Bishop moved to Los Angeles in 1893 with a 6 inch Brashear 
equatorial reflector, installed on Hoover and Adams in his home.
   In 1893, Mount Lowe observatory near Mt. Wilson was opened, with a 16 inch 
Clark telescope and director Lewis Swift.
   Pomona College acquired a 6 inch Brashear refractor in 1894, installed at their 
Frank Brackett Observatory in 1901.
   In 1900, Santa Clara College opened its observatory.  An eight inch Clark 
refractor on a Fauth mount was used at the college for many years.

   The precise determination of latitude provided by the zenith telescope resulted 
in an unwelcome discovery, the 'variation of latitude': periodic changes of 
latitude measured from fixed points on the earth, caused by the wobbling of the 
earth on its polar axis.  The 'International Polar Motion Service' was begun in 
1899, by building six stations around the globe, near 39 degrees North latitude.  
The two American stations were at Gaithersburg, Maryland and Ukiah, California.  
The 1899 buildings at Ukiah still stand, though all the instruments are gone.  
Other buildings were added in 1948, and in the late 1990s, the land was donated to 
the city of Ukiah Parks, who has a goal of completing improvements & opening the 
area to the public.  The city has been accepting proposals from groups wishing to 
include memorial benches, a walking labyrinth, and a peace pole matching 5 others 
in the remaining Latitude Observatories.
   The Ukiah station was an early career experience for several notable 
astronomers.  Frank Schlesinger spent 1899 to 1903 measuring latitude in Ukiah, 
proceeding to Yerkes Observatory and influential work using photography to measure 
stellar parallax, then working as director of Allegheny Observatory from 1905 to 
1920; and director of Yale University Observatory from 1920 to 1941.  Ferdinand 
Neubauer operated the Ukiah station from 1918 to 1922, before working at Lick 
Observatory.  William Meyer of U.C. Berkeley & Lick Observatory also worked Ukiah.
   The International Polar Motion Service was intended to last for one century of 
nightly observations at each station.
   Seth Chandler, the insurance actuary and amateur astronomer who became one of 
the founders of the AAVSO, is credited with the discovery of the variation in 
latitude.
   Astronomical or geographic latitude is measured as the angular distance between 
the direction of gravity and the plane of the celestial equator.   When corrected 
for the 'meridional component of station error', the measurement is the standard, 
geodetic latitude.

   The Coast & Geodetic Survey's first theodolite was by Edward Troughton, built 
1811-14,  weighing over 150 pounds, with a 24 inch circle.  A Troughton theodolite 
with a 30 inch circle was purchased in 1836, but further instruments were lighter 
in weight.
   Both latitude and longitude observations could be made with the large Troughton 
and Simms transit instruments, which functioned as both meridian and zenith 
telescopes, and were used by the Survey from 1847 to 1888.  Typically, vertical 
angles were measured using different instruments than horizontal angle 
measurements.
   The C. & G. S. had a division that designed and built instruments, some of the 
best were circa 1873 products of William Wurdemann.

==========

Bibliography.

Bracher, Katherine.  The First California Observatory.  Mercury, March-April 1985, 
p54.

Campbell, W.W.  Publications of the Astronomical Society of the Pacific 22, #131 
(April 1910) 105-106.

Custer, Clarence P. and Robert W. Birch.  New Focus on a Pioneer Astronomer. 
Griffith Observer 50:9 (Sept. 1986) 15-20.  (Madeira)

(First Amateur Observatory in California).  Sky & Telescope 18:8 (June 1959) 431-
432. 

Killick, Victor W.  California's First Astronomical Observatories.  Sacramento: 
n.p, 1958. 18p.

Killick, Victor.  First Amateur Astronomical Observatory of Record in California. 
Griffith Observer, April 1959, pp56-59.

Lewis, Oscar.  George Davidson, pioneer west coast scientist.  Berkeley: 
University of California Press, 1954. 

Merriam, Marshal.  Letter of 21 October, 2002, on George Madeira.
================

Further references.

Chauvenet, William.  A Manual of Spherical and Practical Astronomy.  Volume Two: 
Theory and Use of Astronomical Instruments.  Fifth edition, 1891.  N.Y.: Dover, 
1960.

(Coast & Geodetic Survey)  1910 Annual Report of the Coast & Geodetic Survey.  
Lists of astronomic stations in US to that date, with map.

(Coast & Geodetic Survey)  Description of the Davidson Meridian Instrument.  
Report of the Superintendent of the U.S. Coast and Geodetic Survey....1879 (App. 
7) 103-109.

Davidson, George.  Astronomical Observations on the Sierra Nevada.  Report of the 
Superintendent of the U.S. Coast Survey....1872 (App. 9) 173-176.

Davidson, George.  Description of the Davidson Meridian Instrument.  United States 
Coast and Geodetic Survey Annual Report (1879), Appendix No. 7.

Davidson, G.  Description of a Zenith Telescope of U. S. Coast Survey.  Monthly 
Notices of the Royal Astronomical Society 28 (April 1868) 181-185.

Davidson, G.  Field Notes on the Zenith Telescope.  Monthly Notices of the Royal 
Astronomical Society 29 (June 1869) 317.

Davidson, George.  The Relative Value of Great and Small Altitudes for 
Astronomical Observations.  Proceedings of the California Academy of Sciences 4 
(Aug. 19, 1872) 251-252.

Dracup, Joseph F.  Geodetic Surveys In The United States, The Beginning And The 
Next One Hundred Years 1807 - 1940.   
http://www.history.noaa.gov/stories/geodetic3.html

(Geodetic Instruments of Precision at the Paris Exposition and in European 
Workshops.)  Washington: National Academy of Sciences, 1878.

Lewis, Oscar.  George Davidson, pioneer west coast scientist.  Berkeley: 
University of California Press, 1954. (inaccuracies)

List of the Published Writings of George Davidson.  Biennial Report of the 
President of the University of California, 1896-1898.  135 items, newspaper 
articles, journal articles, books; 6 headings included astronomical, instruments, 
geodesy.  Many other publications before & after.
1857 AJ... 1.000 12/1857  Davidson, George    Occultations of the Pleiades, 1857 
March 1 
1855 AJ......4..100D   07/1855    Davidson, George   Observations of the solar 
eclipse of 1854, May 26 
1894 AJ.....14...81D   07/1894   Davidson, George  Variation of latitude at San 
Francisco, 1891-1892 
1894 PASP....6..242D   08/1894  Davidson, George   Variations of Latitude in San 
Francisco, as Determined 
1890 MNRAS..50..385D  05/1890   Davidson, G.   the apparent projection of stars 
upon the bright limb of the Moon at occultation.
1884 MNRAS..45Q..58D   11/1884   Davidson, G.   Stars, observed at San Francisco 
1884 MNRAS..45R..58D   11/1884   Davidson, G.   occultations of stars by the Moon, 
1883 
1884 MNRAS..44..268D   03/1884    Davidson, G.   observations of occultations of 
stars by the Moon and of phenomena of Jupiter's satellites, made at Davidson 
Observatory, San Francisco, and at Table Mount Station, California 
1869 MNRAS..29..271D   04/1869     Davidson, G.   On the Practical Speed of 
Electricity through 7200 Miles of Land Wire.
A Few Incidents in My Conferences with Mr. James Lick in the Matter of the Great 
Telescope.  University of California Magazine 5 (April 1899) 131-137.
================================

home page:     http://home.europa.com/~telscope/binotele.htm
Updated 29 October 2002