DDO photometry of E-region stars and equatorial standards. (Paper I).

This paper describes the observations and gives the results of a series of observations of bright E-region stars for use as zero point stars for DDO photometry in the southern hemisphere. The list comprises 45 stars, all brighter than V = 6.0, and gives the colours in the instrumental system with internal s.e. ±0.001 mag and m₄₈ with s.e. ±0.002 mag. The observed m₄₈ is indistinguishable from McClure's system and has the same zero point (±0.002 mag). The individual E-region zero points have been established with s.e. ±0.001 relative to the instrumental system, but the colour equations (and zero point corrections) to transform the instrumental colours to McClure's system have still to be finalised.