Light bending or custom rendering engine? I want to create a short animation of the sun/moon rising and setting.
However I want to include some custom parameters to allow for the bending of light.

To elaborate, I am not talking about refraction here - instead I am talking about a competely new capability of light to bend in an arc that starts horizontal near the ground and gradually ascends into the sky (like an exponential curve). So basically I want to be able to describe how light should travel - not in a straight line but in an arc.

Is there a way that this can be done in blender or do I need custom work done?
If custom work is needed, who should I get in touch with for it? 

Thanks
Nope Cycles cannot bend light in arc nor Blender Internal. Only the renderer Interstellar was rendered in is capable of it as far as I know.

You can bend light with multiple planes with refraction shaders though.

Or you can code your own renderer.