This planner shows the possible imaging times for the specified DSO from my backyard. It incorporates hard-coded values for my location and horizon so it is not a general tool. However, you are free to copy/modify for your own use.
Location: Edison, NJ (Lat 40.5187N, Long -74.4121W)
Horizon limits: approx 32° altitude S and W, 70° altitude N and E.