Yale University Observatory


Yale's first observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...

, the Atheneum, was situated in a tower, which from 1830 housed Yale's first and America's largest refractor, a 5 inches (127 mm) Dollond
John Dollond
John Dollond was an English optician, known for his successful optics business and his patenting and commercialization of achromatic doublets.-Biography:...

 donated by Sheldon Clark
Sheldon Clark
Sheldon Clark was commodore of the Chicago Yacht Club and chairman of the Sinclair Refining Company.-Biography:In 1927 he was charged with jury-fixing in the Fall-Sinclair oil conspiracy trial. In 1929 he was president of the Chicago Stadium Corporation. He died on August 15, 1952.-References:...

. With this telescope Olmsted
Denison Olmsted
Denison Olmsted , U.S. physicist and astronomer, was born at East Hartford, Connecticut. Professor Olmsted is credited with giving birth to meteor science after the 1833 Leonid meteor shower over North America spurred him to study this phenomenon.-Biography:In 1813, he graduated from Yale...

 and Elias Loomis
Elias Loomis
- Life and work :Loomis was born in Willington, Connecticut in 1811. He graduated at Yale College in 1830, was a tutor there for three years , and then spent the next year in scientific investigation in Paris. On his return, Loomis was appointed professor of mathematics in the Western Reserve...

 made the first American sighting of the return of Halley's Comet in 1835. (August 31; seen in Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 August 6, but no news of this had reached America
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

). The telescope was mounted on casters and moved from window to window, but it could not reach altitudes much over 30 deg above the horizon
The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...


Still later, in 1870, a cylindrical turret was added above the tower, so that all altitudes could be reached. The building was demolished in 1893 and the telescope is now at the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

 in Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....

The observatory, in the turret (modelled after the gun turret of the ironclad ship USS Monitor
USS Monitor
USS Monitor was the first ironclad warship commissioned by the United States Navy during the American Civil War. She is most famous for her participation in the Battle of Hampton Roads on March 9, 1862, the first-ever battle fought between two ironclads...

), housed a 9 inches (228.6 mm) Alvan Clark
Alvan Clark
Alvan Clark , born in Ashfield, Massachusetts, the descendant of a Cape Cod whaling family of English ancestry, was an American astronomer and telescope maker. He was a portrait painter and engraver , and at the age of 40 became involved in telescope making...

 refractor donated by Joseph E. Sheffield. The telescope was later housed in the dome on Bingham Hall (the dome later converted to a small planetarium
A planetarium is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation...

, and now used as an experimental aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...


An 8 inches (203.2 mm) telescope financed by E.M. Reed of New Haven was first used for photographing the Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 during the Transit of Venus
Transit of Venus
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun...

 on December 6, 1882.

The observatory also possessed an heliometer
Heliometer is an instrument originally designed for measuring the variation of the sun's diameter at different seasons of the year, but applied now to the modern form of the instrument which is capable of much wider use....

, ordered from Repsold and Sons by H. A. Newton in 1880, delivered in time for measurements of the Transit of Venus
Transit of Venus
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun...

 on December 6, 1882 for determination of solar parallax. This is the same type of instrument that Friedrich Bessel
Friedrich Bessel
-References:* John Frederick William Herschel, A brief notice of the life, researches, and discoveries of Friedrich Wilhelm Bessel, London: Barclay, 1847 -External links:...

 used in 1838 for the first significant determination of a stellar parallax (of the star 61 Cygni
61 Cygni
61 Cygni,Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb. sometimes called Bessel's Star or Piazzi's Flying Star, is a binary star system in the constellation Cygnus...

). Under the direction of W. L. Elkin
William Lewis Elkin
William Louis Elkin was an American astronomer.He was born in New Orleans to Jane and Lewis Elkin, one of five children but the only one to survive to adulthood. Following the death of her husband in 1867, Jane travelled abroad for the following seventeen years, taking along William...

 from 1883 to 1910 the heliometer yielded (according to Frank Schlesinger
Frank Schlesinger
Frank Schlesinger was an American astronomer. His work concentrated on using photographic plates rather than direct visual studies for astronomical research.-Biography:...

) the most (238) and the best parallaxes obtained before the advent of photographic astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...


In the late 1890s, W. L. Elkin built two batteries of cameras equipped with rotating shutters
Shutter (photography)
In photography, a shutter is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene...

 for obtaining the velocities as well as the heights of meteors, pioneering work in the study of meteors.

The Loomis Tower on Canner Street, erected in 1923 in memory of Elias Loomis (1811–1889), was at the time the largest polar telescope in America. The installation was originally designed for the comfort of the observer who sat at the eyepiece
An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes. It is so named because it is usually the lens that is closest to the eye when someone looks through the device. The objective lens or mirror collects light and brings...

 in a warm room at the top of the tower. The tube (beneath the stairs) was parallel to the polar axis of the Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. The building at the base of the tower had a sliding roof and housed a 30 inches (762 mm) optical flat
Optical flat
Optical flats are optical-grade pieces of glass lapped and polished to be extremely flat on one or both sides, usually within a few millionths of an inch . They are used with a monochromatic light to determine the flatness of other optical surfaces by interference...

 coelostat mirror
A mirror is an object that reflects light or sound in a way that preserves much of its original quality prior to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection...

 driven equatorially and reflecting
Reflection (physics)
Reflection is the change in direction of a wavefront at an interface between two differentmedia so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves...

 light from any unobscured part of the sky through both a 15 inches (381 mm) photographic and a 10 inches (254 mm) visual guide
A guide is a person who leads anyone through unknown or unmapped country. This includes a guide of the real world , as well as a person who leads someone to more abstract places .-Guide - meanings related to travel and recreational pursuits:There are many variants of...

 telescope, both of the same focal length
Focal length
The focal length of an optical system is a measure of how strongly the system converges or diverges light. For an optical system in air, it is the distance over which initially collimated rays are brought to a focus...

, 600 inches.

In 1945, the telescope was reversed, with the 15 inches (381 mm) objective at the top, the plate holder at the foot of the tube. The telescope was thus rigidly mounted for photographing the polar region only, for the purpose of investigating the wobbling of the axis of rotation of the earth and redetermining the constants of precession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...

 and nutation
Nutation is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behavior of a mechanism...


The Loomis Telescope was moved to Bethany, Connecticut
Bethany, Connecticut
Bethany is a town in New Haven County, Connecticut, United States. The population was 5,040 at the 2000 census. Bethany was first settled in 1717 but it was not until May 1832 that Bethany separated from Woodbridge to become incorporated as a town. This slightly remote, sparsely populated,...

 in 1957, to continue monitoring the apparent motion of the axis of the earth. Carol Williams analyzed plates for her Ph.D. thesis, 1967. She found apparent motions largely correlated with tidal disturbances of the earth's crust.

External links

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