Dishonored 2: Mission 5: Art Collector 2 of 3

Sneak around to the right of the entrance of the observatory. Down the stairs and into the "restricted area". Inside is a hound. Inside the Quartermasters room is a key to the Archive. To gain acces sneak out of the window to the left of this room, turn right and into the other window. On the wall is the key to the archive. Work your way through the basement area to where the two witches are. That gate by the table is the archive. Enter through the gate and Blink / Far Reach your way around to the back behind the fence.