what's in the way?

Alan sent out a note to the RASC Toronto Centre forums praising SkyTools. He enjoyed my presentation Wednesday night. He also noted a feature he quite likes, for planning purposes, but that I didn't cover.

The further Observing Location customization of Obstructed Horizon allows for further restricted session planning to exclude objects which would not be visible from an observing location due to local obstructions.  Perhaps this facility might be used to plan for objects to be viewed/photographed above a set altitude.

He also noted this is the YouTube video comments.

Indeed. I have used the customised horizon for locations where a lot of the sky is blocked.