  We develop the Ercolani-Sinha construction of SU(2) monopoles and make this
effective for (a five parameter family of centred) charge 3 monopoles. In
particular we show how to solve the transcendental constraints arising on the
spectral curve. For a class of symmetric curves the transcendental constraints
become a number theoretic problem and a recently proven identity of Ramanujan
provides a solution. The Ercolani-Sinha construction provides a gauge-transform
of the Nahm data.
