The observatory is situated on a rising ground forming the left bank of the Tweed, and is at a distance of about fifty yards from the Astronomical Observatory. It is built of wood; copper nails were used, and all iron carefully excluded from the building.

The plan of the observatory is rectangular, 40 feet long by 20 broad: It is divided into one large room to the north, 40 feet by 12, and two ante-rooms to the south, with the lobby and entrance doors between.