EQ Wedges

The function of an EQ Wedge

A EQ Wedge (equatorial wig) is a tilting platform that is placed between a tripod and a mount. It is an essential component for users of a star tracker or an Alt-Az mount who want to photograph deep-sky objects. The wedge allows you to perfectly align the mount's rotation axis parallel to the Earth's axis, a process known as polar alignment.

Why a wedge is necessary

Without a EQ Wedge A mount only moves horizontally and vertically (Alt-Az). Although a computerized system can keep an object in the center of the image, ‘field rotation’ occurs during longer exposures. This makes the stars appear to rotate around the center of the photo. By tilting the mount with a wedge to your location's latitude, you counteract this effect, and stars remain point-shaped during exposures of several minutes.

Accurate adjustment (Latitude & Azimuth)

A quality wedge has fine controls for both elevation (latitude) and horizontal direction (azimuth). These controls are necessary to get the pole star exactly at the right position in the polar finder. A stable wedge also prevents the setting from drifting under the weight of the telescope and camera, which is crucial for consistent tracking throughout the night.

Compatibility and carrying capacity

When choosing an EQ wedge, you need to consider the tripod mount (often 3/8 inch) and the load capacity. The wedge needs to be sturdy enough to support the mount and all accessories without sagging. For mobile setups with a star tracker, a lightweight yet rigid design is the standard.