Answer: altazimuths

AnswerCrossword Clue
altazimuthsA surveying instrument for measuring vertical and horizontal angles, resembling a theodolite but larger and more precise
altazimuthsA telescope on such a mounting
altazimuthsA telescope mounting that moves in azimuth (about a vertical axis) and in altitude (about a horizontal axis)
altazimuthsALTAZIMUTH, an instrument for measuring the altitude and azimuth of heavenly bodies