Design of equatorial instrument

German-style equatorial instrument on display in the public hall of Taipei Astronomical Science Education Center. According to different needs, there are many designs of equatorial plane, and each design has its advantages and disadvantages. The prototype of the German equatorial telescope is like a huge T-shape. The right ascension axis is installed on a pedestal perpendicular to the ground, and the built-in polar telescope is aimed at the celestial pole according to the inclination of geographical latitude. There is a bearing at the T-joint, which makes the right ascension shaft combine with the base and rotate. The declination axis is vertically placed near the center of the declination axis. The improved German declination instrument moves the declination axis from the position near the center to the other end of the declination axis.

The telescope is fixed at one end of the declination axis, and a counterweight (or other things such as sandbags) with appropriate weight is installed at the other end to maintain balance and prevent the tracking device from being damaged. The German equatorial telescope is the most commonly used telescope (for observation or astrophotography). It is widely used from 6 cm (2.4 inches) refractor to 35 cm (14 inches) Schmidt-Cassegrain reflecting telescope. The yoke declination instrument makes the declination shaft into a frame, and the two ends are supported by brackets, and the declination shaft is installed in the frame near the center. The telescope is completely placed in the frame and covers the declination axis (some do not, such as the 2.5m reflecting telescope at Mount Wilson Observatory). Unlike the German declination meter, the yoke declination meter does not need additional accessories for balance.

Because the telescope of the former "Yoke Equatorial Telescope" is placed in the frame, it is not conducive to observing celestial bodies near the celestial pole. For example, the fork equatorial telescope of Haier telescope changed its northern end into a huge horseshoe shape to observe celestial bodies near the north celestial pole.