Multireference configuration interaction (MRD-CI) calculations are performed to compute the electronic spectra of the three low-lying isomers of C5H, a molecule of radio-astronomical interest. The electronic spectrum of linear C5H is dominated by two transitions computed at 4.13 eV ((2)Pi <-- X-2 Pi) and 6.11 eV ((2)Pi <-- X(2)Pi). The first dipole-allowed transition is calculated at 2.54 eV ((2)Delta <-- X(2)Pi). Further relatively strong excitations are obtained at 2.71 eV ((2)Sigma <--X(2)Pi) and 4.00 eV ((2)Pi <-- X(2)Pi). The first dipole-allowed excitation of a C-2v symmetric ring-chain isomer is calculated at 1.27 eV ((2)A(1) <-- (XB2)-B-2). Up to 3.61 eV ((2)A(2) <-- (XB2)-B-2), no other dipole-allowed transitions are obtained, whereas the spectrum of a C, symmetric ring-chain structure shows several dipole-allowed excitations in the energy interval between 0.85 and 2.53 eV, including a dominating transition computed at 1.67 eV ((2)A' <-- X(2)A').