equatorial

Etymology

adj

1. of, near, or relating to the equator
   That plant is best suited to equatorial climates.
2. (organic chemistry) perpendicular to the plane of a ring

noun

1. (astronomy) A kind of telescope mounted so as to have two axes of motion at right angles to each other, one of them parallel to the axis of the Earth, and each carrying a graduated circle, one for measuring declination, and the other right ascension, or the hour angle, so that the telescope may be directed, even in the daytime, to any star or other object whose right ascension and declination are known.