The Looking Glass

The Looking Glass is a massive sunshade placed in orbit around Big Comet, carefully balanced so that it maintains it's position in the Lagrange 1 point. Due to the eccentricity of Big Comet, plasma thrusters lining the edge of the disc must regularly be fired to keep it's position. These are powered by the disc itself, which holds secondary photovoltaic capabilities.

Most of the harmful radiation coming from Sirius A is not in fact in the visible wavelength, so the disc is mostly transparent to visible light. It's primary purpose is to block of ultraviolet, X-ray and neutron radiation. Despite the disc's impressive size (over 100 kilometers in diameter), it can only occlude a rather small portion of BC's surface. This point on the equator of the planet has grown into a very successful permanent habitation known as Haven, which is home to millions of people.