Evaluation of parallax in Friedmann universes

The dependence of parallax on redshift is evaluated for homogeneous Friedmann universes, following a suggestion by Weinberg that space curvature might be evaluated thereby. Although the method is valid in principle, the only interesting variations in parallax are near the antipode in closed models. The prospects for seeking secular parallax for distant sources even in such models are poor unless our velocity through the microwave background exceeds Conklin's limit, or unless it proves possible to use source structure resolved at less than 10-4 arcsec, over a long time base.An apparent discrepancy between Weinberg's and McCrea's values for parallax distance is resolved