You would better off getting a "commercial" skylight...this is one area not to DIY in cobbling something together.
I am no expert on windows .. but what little I know? sliding and ceilings.. do not dance on the same floor!
Yup...but what do you mean by sliding? Sounds like a recipe for leaks...and a disaster. What are you trying to accomplish?
Thank you all for your advise....will stay away from the possible leaks:-)