astronomical transit instrument
Quick Summary
Astronomical transit instruments are specialized telescopes crucial for mapping the celestial sphere. These instruments, typically refractors with apertures of 6 to 8 inches, are designed to move only in the plane of the observer's meridian, an imaginary line passing through the north and south points of the horizon and the zenith. This restricted motion, known as transiting the meridian, allows for precise observation of celestial bodies as they cross this line.
Invented by Danish astronomer Ole Rømer, transit instruments help determine celestial objects' right ascension and declinations. The data collected is vital for creating star and planetary catalogs. Examples include the transit circle telescope and the horizontal meridian circle telescope.12
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