with one of the two Riefler clocks on a pier. A switchboard in this room directed signals from the observatory to the offices in Chicago. The south wall features a double-hung window. Also to the south is a Warner & Swasey chronograph, used to record the star observations. Also found in the chronograph room were the two auxiliary clocks to the master clocks. These too were Rieflers. One was No. 237 and the other was No. 240. Both clocks are no longer present in the building. A steel doors leads to the entrance of the observatory segment, where there is a stairway to the second floor and a small lavatory. A set of airlock style doors leads to a temperature controlled room with two of the four Riefler clocks on one of the piers. In the clock vault there were 58 light bulbs positioned on the floor. The bulbs would go on and off in accordance to the demand for temperature. The vault was to be maintained at a constant 81 degrees F. These bulbs along with a ventilation shaft could maintain a temperature to within a half of a degree of 81. The two Riefler clocks found in the vault was No. 220 and No. 224. Above the room is a Warner & Swasey celestial transit instrument, on its own pier. The observatory segment is a two-story, concrete, domed octagon, covered with sheet metal. A opening allows observations by the telescope. Steel shutters can close this through a system of chains. Each steel shutter weighed one-half a ton. It was written that the gearing used to open the doors were so easy a child of six could do it. The office segment is to the west. The first floor segment is with two double-hung windows on both the south and west walls. Shelves and cabinets remain in the room from when it was in use. The floor is carpet-covered hardwood and the walls are lath and plaster. The second story of the office segment was the sleeping room, where astronomers could sleep. It originally featured a basin and a cot, with two double-hung windows again on the south and west. In 1926, this room was converted into a radio room to transmit short-wave signals. A vintage 1947 Collins transmitter is still in the room. A staircase in the northeast of this room leads to the tin roof, now covered