Observed lines of HSC within the observed frequency range. The abscissa corresponds to the rest frequency assuming a velocity with respect to the local standard of rest of 5.83 km s⁻¹. The ordinate is the antenna temperature corrected for atmospheric and telescope losses in milliKelvin. Spectral resolution is 38.15 kHz. The red line shows the synthetic spectrum for T_r = 5 K and N = (5.50 ± 0.50) × 10¹².