e·qua·to·ri·al 
(ē′kwə-tôrē-əl, ĕk′wə-)
(ē′kwə-tôrē-əl, ĕk′wə-)adj.
1.
a. Of, relating to, or resembling the earth's equator.
b. Relating to conditions that exist at the earth's equator: equatorial heat.
2. Being or having a mounting with two perpendicular axes, one of which is parallel to the earth's rotational axis, allowing a telescope so mounted to track a celestial object for long periods with adjustments only to that axis.
n.
A telescope having an equatorial mounting.
e′qua·tori·al·ly adv.