Making Glass

How do I do a nice looking glass?

Specifically:
It is a half-sphere, it is between a scene and a starry background. I want it to reflect the scene and still have the stars look nice.

TIA

Grrr… It’s not posting.

yafray is best for doing glass. once you enable it, you’ll notice some presets in the raytracing menu in materials. two are for glass.