Pentagrammic antiprism

The pentagrammic antiprism, or stap, is a prismatic uniform polyhedron. It consists of 10 triangles and 2 pentagrams. Each vertex joins one pentagram and three triangles. As the name suggests, it is an antiprism based on a pentagram. It is one of two pentagrammic antiprisms, the other one being the pentagrammic retroprism. In this case, the pentagrams are aligned with one another.

Vertex coordinates
A pentagrammic antiprism of edge length 1 has vertex coordinates given by:
 * $$\left(±\frac12,\,-\sqrt{\frac{5-2\sqrt5}{20}},\,±\sqrt{\frac{\sqrt5-1}8}\right),$$
 * $$\left(±\frac{\sqrt5-1}4,\,\sqrt{\frac{5+\sqrt5}{40}},\,±\sqrt{\frac{\sqrt5-1}8}\right),$$
 * $$\left(0,\,-\sqrt{\frac{5-\sqrt5}{10}},\,±\sqrt{\frac{\sqrt5-1}8}\right).$$

Related polyhedra
Two non-prismatic uniform polyhedron compounds are composed of pentagrammic antiprisms:


 * Small snub dodecahedron (6)
 * Small disnub dodecahedron (12)

There are an infinite amount of prismatic uniform compounds that are the antiprisms of compounds of pentagrams.