Pointing Your Telescope; Equatorial Mount - SKY-WATCHER EQ6 Instruction Manual

A German Equatorial mount has an adjustment, sometimes called a wedge, which tilts the mount's polar axis
so that it points at the appropriate Celestial Pole (NCP or SCP). Once the mount has been polar aligned, it
needs to be rotated around only the polar axis to keep an object centred. Do not reposition the mount base or
change the latitude setting. The mount has already been correctly aligned for your geographical location (ie.
Latitude), and all remaining telescope pointing is done by rotating the optical tube around the polar (R.A.) and
declination axes.
A problem for many beginners is recognizing that a polar-aligned equatorial mount acts like an alt-azimuth
mount which has been aligned to a celestial pole. The wedge tilts the mount to an angle equal to the
observer's Latitude, and therefore it swivels around a plane which parallels the celestial (and Earth's) equator
(Fig.i). This is now its "horizon"; but remember that part of the new horizon is usually blocked by the Earth.
This new "azimuth" motion is called Right Ascension (R.A). In addition, the mount swivels North(+) and South(-
) from the Celestial Equator towards the celestial poles. This plus or minus "altitude" from the celestial equator
is called Declination (Dec).
Fig.i
Right
Ascension
Meridian
W
Line
S
Plane of local horizon

Equatorial Mount

(Northern Hemisphere)
Zenith
Object you
are viewing
Declination
Nadir
14
Mount aligned on
North Celestial Pole
Polaris
E
Plane of Celestial
Equator
Latitude
N
Apparent
movement
of stars