The skylight could be created by slicing the ribs and webbing using an extruded arc. The SLICE command utilizing the SURFACE option would do the trick.
As for creating the "lattice work" affect I imagine you would have to create the required profiles, locate them properly (i.e.-relative to the curved webs), extrude them through the webs, then do a subtraction.
That's how I view it. If you are patient I am sure other forum members, more knowledgeable than myself, will post alternate suggestions.