transit instrument or transit, telescope devised to observe stars as they cross the meridian and used for determining time. Its viewing tube swings on a rigid horizontal axis restricting its movements to the arc of the meridian. In the field of view of the eyepiece are threads of spider web or fine lines ruled on thin glass. The threads or lines are parallel in a north-south direction and odd in number. Precise adjustment places the middle line exactly on the meridian. After the observer has noted the times at which each line is passed by the star, he averages them to learn the instant at which the star was on the meridian. In modern transits, known as meridian circles or meridian telescopes, the observer merely presses a button as the star crosses each line. Electrical impulses are recorded on a revolving drum at one or two second intervals as they pass through a chronograph. The meridian circle is equipped with precisely graduated circles mounted on the horizontal axis. Stationary verniers, or reading microscopes, mounted on the fixed supports of the telescope enable the observer to read the circles. The meridian telescope gives the altitude of a star as well as the transit time. This information yields the right ascension and declination, i.e., the location of the star in the celestial sphere. The meridian circle has largely replaced the transit as the equipment of observatories, although the older transit instrument is still used to some extent for determining sidereal time. For a discussion of the transit used by engineers, see surveying.
"transit instrument." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (February 17, 2019). https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/transit-instrument
"transit instrument." The Columbia Encyclopedia, 6th ed.. . Retrieved February 17, 2019 from Encyclopedia.com: https://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/transit-instrument
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.