|
accessory: used here to refer to any associated parts of an instrument such as tripod base and legs.
|
age of the moon: number of days that have passed since the previous new moon.
|
alidade: straight rule with sights. An alidade could be used for surveying with a plane table but it also appears in a different form as part of an astrolabe.
|
almucantars: lines of equal altitude on a projection of the heavens based on the local horizon.
|
altazimuth theodolite: theodolite for measuring altitude and azimuth simultaneously, see article on the theodolite.
|
altitude: angle above and perpendicular to the horizon, or an angular elevation above the horizontal direction in the same azimuth.
|
altitude dial: sundial measuring time from the altitude of the sun.
|
armillary sphere: set of rings corresponding to the circles of the celestial sphere, see article on the armillary sphere.
|
aspectarium: aide-memoire which depicts the astrologically significant angles (or aspects) between the planets.
|
astrolabe: astronomical instrument based on a planispheric projection of the heavens, see article on the astrolabe.
|
astrolabe quadrant: quadrant that has many of the lines and functions of the ordinary astrolabe, projected for a single latitude.
|
astrolabum catholicum: type of universal astrolabe, see article on the astrolabe.
|
astrological houses: 12-part division of the heavens centred on the celestial pole, also called 'houses of heaven', see article on the astrolabe.
|
astrological instrument: an instrument whose primary use was for astrological purposes, such as casting horoscopes, rather than for observational astronomy.
|
astronomical clock: a clock incorporating astronomical instruments such as an astrolabe or armillary sphere.
|
astronomical compendium: several instruments compiled into one device, see article on the astronomical compendium.
|
