The Yale University Observatory, also known as the Leitner Family Observatory and Planetarium, is an

astronomical Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include ...

observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Th ...

owned and operated by

Yale University Yale University is a Private university, private Ivy League research university in New Haven, Connecticut, United States. Founded in 1701, Yale is the List of Colonial Colleges, third-oldest institution of higher education in the United Stat ...

, and maintained for student use. It is located in Farnham Memorial Gardens near the corner of Edwards and Prospect Streets,

New Haven New Haven is a city of the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound. With a population of 135,081 as determined by the 2020 U.S. census, New Haven is the third largest city in Co ...

Connecticut Connecticut ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Rhode Island to the east, Massachusetts to the north, New York (state), New York to the west, and Long Island Sound to the south. ...

. In the 21st century, the Yale Student Observatory, the Leitner observatory also has public outreaches and supports astronomy for students of the college. However, the Yale Observatory traces its history back to being one of the first formal institutions for astronomical observation in the United States, dating to the 1830s.

History

In 1828 Sheldon Clark donated 1200 US dollars to Yale to procure a Dollond refracting telescope. Yale's first

, the Atheneum, was founded in 1830, situated in a tower. From 1830 it housed Yale's first

refractor A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens as its objective to form an image (also referred to a dioptric telescope). The refracting telescope design was originally used in spyglasses and ...

, a Dollond donated by Sheldon Clark. It was the largest in the United States at the time. With this telescope

Olmsted Olmsted may refer to: People * Olmsted (name) Places * Olmsted Air Force Base, inactive since 1969 * Olmsted, Illinois * Olmsted County, Minnesota * Olmsted Falls, Ohio * Olmsted Point, a viewing area in Yosemite National Park * Olmsted To ...

and

Elias Loomis Elias Loomis (August 7, 1811 – August 15, 1889) was an American mathematician. He served as a professor of mathematics and natural philosophy at Case Western Reserve University, Western Reserve College (now Case Western Reserve University), the ...

made the first American sighting of the return of

Halley's Comet Halley's Comet is the only known List of periodic comets, short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30) occurring after ...

on 31 August 1835. (It had been seen in Europe on 6 August, but no news of this had reached the United States.) The telescope was mounted on casters and moved from window to window, but it could not reach

altitudes Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical s ...

much over 30 deg above the

horizon The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This curve divides all viewing directions based on whethe ...

. In 1870, a cylindrical turret was added above the tower, so that all altitudes could be reached. In the same year a 9-inch Alvan Clark refractor was mounted in the observatory. The building was demolished in 1893 and the telescope is now at the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase a ...

Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

The observatory, in the turret (modelled after the gun turret of the ironclad ship USS ''Monitor''), housed a

Alvan Clark Alvan Clark (March 8, 1804 – August 19, 1887) was an American astronomer and telescope maker. Biography Born in Ashfield, Massachusetts, Clark started as a portrait painter and engraver (c.1830s–1850s), and at the age of 40 became involved ...

donated by

Joseph E. Sheffield Joseph Earl Sheffield (June 19, 1793 – February 17, 1882) was an American railroad magnate and philanthropist. Sheffield was born in Southport, Connecticut, the son of Paul King Sheffield, a shipowner, and his wife Mabel (née Thorpe). ...

. The telescope was later housed in the dome on Bingham Hall (the dome later converted to a small

planetarium A planetarium (: planetariums or planetaria) is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation. A dominant feature of most planetariums is ...

, and now used as an experimental

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

). An telescope financed by E.M. Reed of

was first used for photographing the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

during the

Transit of Venus A transit of Venus takes place when Venus passes directly between the Sun and the Earth (or any other superior planet), becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Venus is visible as ...

on December 6, 1882. The observatory also possessed a

heliometer A heliometer (from Greek ἥλιος ''hḗlios'' "sun" and ''measure'') 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 instrumen ...

, ordered from Repsold and Sons by H. A. Newton in 1880, delivered in time for measurements of the

on December 6, 1882 for determination of

solar parallax The most important fundamental distance measurements in astronomy come from trigonometric parallax, as applied in the '' stellar parallax method''. As the Earth orbits the Sun, the position of a nearby star will appear to shift slightly agains ...

. This is the same type of instrument that

Friedrich Bessel Friedrich Wilhelm Bessel (; 22 July 1784 – 17 March 1846) was a German astronomer, mathematician, physicist, and geodesy, geodesist. He was the first astronomer who determined reliable values for the distance from the Sun to another star by th ...

used in 1838 for the first significant determination of a

stellar parallax Stellar parallax is the apparent shift of position (''parallax'') of any nearby star (or other object) against the background of distant stars. By extension, it is a method for determining the distance to the star through trigonometry, the stel ...

(of the star

61 Cygni 61 Cygni is a binary star system in the constellation Cygnus (constellation), Cygnus, consisting of a pair of K-type main-sequence star, K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitu ...

). Under the direction of W. L. Elkin from 1883 to 1910 the heliometer yielded (according to

Frank Schlesinger Frank Schlesinger (May 11, 1871 – July 10, 1943) was an American astronomer. His work concentrated on using photographic plates rather than direct visual studies for astronomical research. Biography Schlesinger was born in New York City and a ...

) the most (238) and the best parallaxes obtained before the advent of

photographic Photography is the art, application, and practice of creating images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many ...

astrometry Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other Astronomical object, celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, th ...

. In the late 1890s, W. L. Elkin built two batteries of

cameras A camera is an instrument used to capture and store images and videos, either digitally via an electronic image sensor, or chemically via a light-sensitive material such as photographic film. As a pivotal technology in the fields of photograp ...

equipped with rotating

shutters A window shutter is a solid and stable window covering usually consisting of a frame of vertical stiles and horizontal rails (top, centre and bottom). Set within this frame can be louvers (both operable or fixed, horizontal or vertical), solid ...

for obtaining the

velocities Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector quantity, meaning that both m ...

as well as the heights of

meteors A meteor, known colloquially as a shooting star, is a glowing streak of a small body (usually meteoroid) going through Earth's atmosphere, after being heated to incandescence by collisions with air molecules in the upper atmosphere, creating a ...

, 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 Optical telescope, telescopes and microscopes. It is named because it is usually the lens that is closest to the eye when someone looks thro ...

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 only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

. The building at the base of the tower had a sliding roof and housed a

optical flat An optical flat is an Optics, optical-grade piece of glass lapping, lapped and polishing, polished to be extremely flat on one or both sides, usually within a few tens of nanometres (billionths of a metre). They are used with a monochromatic li ...

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