Deep electronographic photometry has been performed down to mv 21.7 with the 90 mm McMullan camera on the Danish 1.54 m telescope at La Silla. Three exposures per colour were obtained. The plates have been scanned with the Geneva microdensitometer. The selected stars are isolated and are located in the outer corona. The magnitudes are obtained by the profile fitting method, cf. Blecha (1982), which enhances the dynamical range of the plate and reduces the noise due to crowding. The random error appears magnitude independent down to mv = 21 with σ = .05 per colour. Below mv = 20 a number of galaxies were identified and rejected according to their image profiles.