it is not standard observing procedure, because the sky noise at 115 GHz dominates at this level of receiver performance. On the best dry, cold days the total system temperatures are less than 350 K SSB, referred to above the atmosphere. Spectrometer The telescope has two software-selectable filter banks of a modified NRAO design, each containing 256 channels. At 115 GHz, the 0.5 MHz per channel filter bank provides a velocity resolution of 1.3 km/s, and velocity coverage of 333 km/s, and the resolution and coverage of the 0.25 MHz per channel filter bank are 0.65 and 166 km/s, respectively. The spectrometers divide the 150 MHz final IF signal from the receiver into 16 bands of 4 or 8 MHz width, each centered on 8 MHz. The 16 bands are passed to an equal number of filter boards, each with 16 contiguous two-pole Butterworth filters of 0.25 or 0.5 MHz width. The outputs of the filters are passed to square law detectors. After amplification, the detected signals are accumulated in integrators. The sampling time is 48 ms, followed by a 5 ms hold for sequential read-out by an analog-to-digital converter, after which the integrators are cleared for the next cycle. The 256 values produced by the converter are stored in a buffer during the following cycle, allowing the computer a full 48 ms to read the data. Computer system Prior to January 1991, pointing, data taking, and calibration of the radio telescope were controlled by a Data General Nova minicomputer ( picture ) running a custom telescope-control system. The control computer was fairly limited in speed and memory (having only 32 K byte of random access memory and 5 M byte of fixed disk storage), but it was fast enough to allow limited data reduction on-line. For further processing, all scans were transferred via 1600 bpi 9-track magnetic tape to a Digital Equipment VAXstation II/GPX workstation. In January 1991, the telescope-control functions were transferred to a Macintosh IIfx computer, running a translated and improved version of the telescope-control system written in C. Individual scans or more commonly concatenated files containing large numbers of scans can be obtained from the control computer directly over the Internet. Generally the data is analyzed as FITS-format "cubes" of galactic longitude, latitude, and velocity. Such cubes can be built from the raw scan files either using custom Macintosh software or on Unix workstations with IDL