Graham made for Edmond Halley the great mural quadrant at Greenwich Observatory, and also the fine transit instrument and the zenith sector used by James Bradley in his discoveries.
12.
A photographic plate was placed in the focus of a transit instrument and a number of short exposures made, their length and the time being registered automatically by a clock.
13.
The transit circle was capable of determining both right ascension and declination of a star, unlike the more simple and common transit instrument that can only determine the right ascension.
14.
In the geographical tussle, Greenwich, England, holds a distinct edge, as the home of the Prime Meridian, which passes through the center of the transit instrument at the Old Royal Observatory.
15.
While at Hopkins, his astronomy duties consisted of caring for the astronomical transit instrument and the clocks in the little observatory behind the physics laboratory, and the 9.5-inch refractor in the dome of the laboratory roof.
16.
These plates were to be reproduced and distributed as a set of charts, the Carte du Ciel, in contrast to previous sky charts which had been constructed from the celestial coordinates of stars observed by transit instruments.
17.
He wrote " Annals of the Observatory of Georgetown College, D . C ., containing the description of the observatory and the description and use of the transit instrument and meridian circle " ( New York, 1852 ).
18.
The asteroids Asia, Sappho, Sylvia, Camilla, Vera and the Variable stars Y Virginis, U Scorpii, T Sagittari, Z Virginis, X Capricorni and R Reticuli were first discovered visually at Madras with the transit instrument or by the equatorial instruments.
19.
In the United Kingdom, the transit instrument and mural circle continued until the middle of the 19th century to be the principal instrument in observatories, the first transit circle constructed there being that at Greenwich ( mounted in 1850 ).
20.
The bell, which weighs over, was cast by Naylor & Co . and the clock was built by Boston firm Howard & Co . Time was recorded via a subterranean transit instrument which was used to observe the passage of stars.
