declinator

from The Century Dictionary.

• noun An instrument used in ascertaining the declination, as in dialing, of a plane, and in astronomy, of the stars. Also declinatory.
• noun One who declines to join or agree with another; a dissentient.

from the GNU version of the Collaborative International Dictionary of English.

• noun An instrument for taking the declination or angle which a plane makes with the horizontal plane.
• noun rare A dissentient.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An instrument for taking the declination or angle which a plane makes with the horizontal plane.
• noun obsolete A dissenter.