The 3CR catalogue of extragalactic radio sources is now completely identified for b > 15° and redshifts have been determined for > 98% of them (see Djorgovski et al. 1988 for the latest update). The radio galaxies in this catalogue span the redshift range from 0 to 2.48. This sample provides us with a unique opportunity to examine the optical and radio properties of a complete sample over a look-back time comparable to the Hubble time.

We present visual and near-infrared Hubble diagrams for first-ranked cluster galaxies, and moderate-flux and high-flux radio galaxies. The photometric improvements and the extension of the diagrams to large redshifts (up to z ≃ 1.8) for both 3CR and “1 Jy” class radio galaxies are highlighted. The absolute luminosities of these three types of “standard candles”, where their redshifts overlap, agree adequately. The near-IR (2μm) Hubble diagrams may be used to determine the global deceleration parameter, q0, and the current data favor q0 ∼ +0.2 to +0.3. The sensitivity to evolutionary changes in the giant galaxies is quite modest at these long wavelengths. On the other hand, the visual regime (BV R) shows a dramatic dependence on differential evolution effects, which dominate over the cosmological model differences. Most radio galaxies apparently have had active star formation, with a continually declining rate, but a few are quite faint and red; they may have had a relatively passive evolution.

I discuss four optical methods to locate standard candles (giant E galaxies), which should eventually lead us to reasonably large samples at high z. Redshift criteria and determinations are briefly discussed. The observed faint galaxy colors fit well into a simple model of stellar (galactic) evolution for systems with star-formation confined to a short time interval. Finally a summary of the statistics of blue galaxies in Coma-like clusters (Butcher-Oemler effect) is presented and interpreted.