The first thing to say is that if you are using an equatorial mount that comes with manufacturers instructions, then refer to those. For instance ‘GOTO’ mounts will have their own elaborate set-up procedures that should be followed for the best results. The notes I give here will be useful in the absence of instructions, particularly for the simpler models of equatorial mounting.

A good telescope mounting will have provisions for making fine adjustments to the elevation and azimuth (east–west pointing) of the polar axis. Sometimes they also have polar-alignment telescopes built into the polar axes. The eyepieces of these are fitted with a graticule of specially marked lines, and/or circles, and divisions. Using these and a chart of the area around the celestial pole (or following other supplied instructions) one can achieve a polar alignment to within a fraction of a degree accuracy.

How accurately does your telescope mount have to be aligned? The answer to that depends on what you intend doing with it. Simple visual observation is made all the easier if the polar axis is aligned within a couple of degrees of the true pole. Adjustments made in response to a squint along the polar axis may well be good enough, especially if the mount is fitted with a declination slow motion. Of course, observing is made more convenient, and hence more pleasurable, if the alignment is better than that. Photography involving exposures of a small fraction of a second is also uncritical of polar alignment.