The Orrery of Thessalia
The Crystal Shell of Orreryspace is a vast flat glass plane. The phlogiston is not visible through it; rather, it is possible to see the rest of the system by peering into the mirrored surface of the shell. Indeed, Firman’s Observatory is founded precisely on this principle and floats close to the shell at all times so the insane mage Firman can peer at any location in Orreryspace. With a powerful enough seeing lens, he claims, you can watch the grass grow on Thessalia.
Uniquely within Orreryspace, there are crystalline spheres of complete transparency within the crystal shell, upon which ride the stars and several of the planets. The first can be located at Track #3 on the inner planet display, bearing the sun Hortus. The next is located on track #5 on the outer display, bearing the shimmering cube of water called Ondus. The next appears at track #6, carrying Delving and the next at #9 carrying Burot. The last sphere is located at track #18, carrying a number of small blazing objects that are in fact elemental prisons from the system’s early history. These are the “stars” as seen from Thessalia.
These spheres are not permeable, but do have gaps in the form of large planetoid sized holes which can be traversed. As they move, they are said to “sing,” and one can find the gaps by listening carefully. Of course, charts and magical astrogation devices have been created to assist in transversing them. Slamming into a crystal sphere will inevitably destroy a spelljammer, as the sphere is infinitely hard. Nothing, not magic or material, known to any race has been able to puncture them.
RELIGIONS OF ORRERYSPACE