User's Manual

Fig 18

2.3.1 Pointing to the North Celestial Pole (NCP) (fig. 18)

For the following examples, it is assumed that the observing site is in the

Northern Hemisphere. In the first case (Fig.18, mid position), the optical tube is

pointing to the NCP. This is its probable position following the polar-alignment

step. Since the telescope is pointing parallel to the polar axis, it still points to the

NCP as it is rotated around that axis counter-clockwise (Fig.18, left position), or

clockwise (Fig.18, right position).

2.3.2 Pointing toward the western or eastern horizon (fig. 19)

Now, consider pointing the telescope to the western or eastern horizon. If the

counterweight is pointing North, the telescope can be swivelled from one

horizon to the other around the Dec axis in an arc that passes through the NCP

(any Dec arc will pass through the NCP if the mount is polar-aligned). It can be

seen then that if the optical tube needs to be pointed at an object north or south

of this arc, it has to be also rotated around the R.A

Celestial Pole