There are two main kinds of telescope mounts, alt-azimuth and
equatorial. Most books on astronomy recommend the equatorial
mount, which is aligned with the Earth’s axis of rotation so
that a simple motor on that axis will move the telescope in one
direction while the Earth turns in the other direction, the end
result being that the telescope’s aim remains fixed in space,
pointing at a distant object. This is essential for long-
exposure imaging but it’s also desirable for many kinds of
visual observation. Despite all the advantages of the equatorial
mount, the simpler alt-azimuth design retains a devoted
following. It is simple to use, basically “point and shoot,”
and, because it requires no counterweights, relatively light in
weight for the telescope it carries. The very popular Dobsonian
telescope uses a simple version of the alt-azimuth mount. Its
main disadvantage is that tracking an object across the sky
always requires simultaneous motions in two different
directions. With a badly designed mount, this ca