def test_cos_to(self, a0, h0, a1, h1):
a = Horizontal(a0, h0)
b = Horizontal(a1, h1)
pa = a.to_point()
pb = b.to_point()
expected = -((pa - pb).length**2 - pa.length**2 - pb.length**2) / (
2 * pa.length * pb.length)
self.assertEqual(a.cos_to(b), expected, epsilon=self.EPS)
def project_star(self,
pos: Horizontal,
star: Star,
always_project: bool = False):
diameter = self._get_size(star.magnitude if star is not None else -1)
in_eye = self.watcher.radius_low_bound < self.watcher.see.cos_to(
pos) <= 1
if in_eye or always_project:
delta = pos.to_point() - self.watcher.see.to_point()
prj_delta = delta.rmul_to_matrix(
self.watcher.transformation_matrix)
dx, dy = self.distortion(prj_delta.x, prj_delta.y,
self.watcher.radius, prj_delta.z)
diameter, _ = self.distortion(diameter, 0, self.watcher.radius,
prj_delta.z)
cx, cy = self.centre[0] + dx, self.centre[1] + dy
return ProjectedStar(cx, cy, pos, diameter, star, in_eye)