This paper examines how notions of equity are being evoked by expert advocates of more research into solar geoengineering. We trace how specific understandings of equity figure centrally-although not always explicitly-in these expert visions. We find that understandings of equity in such ''vanguard visions'' are narrowly conceived as epistemic challenges, answerable by (more) scientific analysis. Major concerns about equity are treated as empirical matters, requiring scientific assessment of feasibility, risks, or ''win-win'' distributive outcomes and optimizations, with concurrent calls to delimit risk or reduce scientific uncertainties. We argue that such epistemic framings sidestep, inter alia, the inequality in resources available to diverse non-experts-including the ''vulnerable'' evoked in expert visions-to project their own equity perspectives onto imagined technological pathways of the future. These may include concerns relating to moral or historical responsibility and/or lack of agency in shaping the directions of innovation. We conclude that the performative power and political implications of specific expert visions of equity, evoked as a rationale to undertake solar geoengineering research, require continued scrutiny.