The CN Molecule and the Cosmic Background Radiation Temperature

We have remeasured the rotational temperature of the CN molecule ground state in the direction of the Ophiuchi using the ESO 1.4 meter CAT telescope and associated Coude Echelle Spectrograph. These measurements determine: a) a very precise value of cosmic background radiation (CBR) temperature at A2.64 rwn, b) a new value for the intrinsic line width of the CN absorption lines, and c) a measure of the CBR temperature at A1.32 mm. We present each of these results briefly here and refer the reader to the paper of Crane et al. (1986) for further details of our results and to the review of Thaddeus (1972) and the paper of Meyer and Jura (1985) for more details of the technique.