  $GdTe_{3}$ is a layered antiferromagnet which has attracted attention due to
its exceptionally high mobility, distinctive unidirectional incommensurate
charge density wave (CDW), superconductivity under pressure, and a cascade of
magnetic transitions between 7 and 12 K, with as yet unknown order parameters.
Here, we use spin-polarized scanning tunneling microscopy to directly image the
charge and magnetic orders in $GdTe_{3}$. Below 7 K, we find a striped
antiferromagnetic phase with twice the periodicity of the Gd lattice and
perpendicular to the CDW. As we heat the sample, we discover a spin density
wave with the same periodicity as the CDW between 7 and 12 K; the viability of
this phase is supported by our Landau free energy model. Our work reveals the
order parameters of the magnetic phases in $GdTe_{3}$ and shows how the
interplay between charge and spin can generate a cascade of magnetic orders.
