  High cadence observations of solar activity (active regions, flares,
filaments) in the H$\alpha$ line were performed at Meudon and Haute Provence
Observatories from 1956 to 2004. More than 7 million images were recorded,
mainly on 35 mm films. After a review of the scientific interest of solar
surveys at high temporal resolution and the historical background, we describe
the new instrument which will operate automatically in 2020 at the Calern
station of the C\^{o}te d'Azur observatory (1270 m). It will replace the former
heliographs with improved cadence, seeing and time coverage. We summarize the
capabilities of the optical design and present new scientific perspectives in
terms of flare onset and Moreton wave detection.
