  Detecting cosmic gamma rays at high rates is the key to time-resolve the
acceleration of particles within some of the most powerful events in the
universe. Time-resolving the emission of gamma rays from merging celestial
bodies, apparently random bursts of gamma rays, recurring novas in binary
systems, flaring jets from active galactic nuclei, clocking pulsars, and many
more became a critical contribution to astronomy. For good timing on account of
high rates, we would ideally collect the naturally more abundant, low energetic
gamma rays in the domain of one giga electronvolt in large areas. Satellites
detect low energetic gamma rays but only in small collecting areas. Cherenkov
telescopes have large collecting areas but can only detect the rare, high
energetic gamma rays. To detect gamma rays with lower energies,
Cherenkov-telescopes need to increase in precision and size. But when we push
the concept of the -- far/tele -- seeing Cherenkov telescope accordingly, the
telescope's physical limits show more clearly. The narrower depth-of-field of
larger mirrors, the aberrations of mirrors, and the deformations of mirrors and
mechanics all blur the telescope's image. To overcome these limits, we propose
to record the -- full/plenum -- Cherenkov-light field of an atmospheric shower,
i.e. recording the directions and impacts of each individual Cherenkov photon
simultaneously, with a novel class of instrument. This novel Cherenkov
plenoscope can turn a narrow depth-of-field into the perception of depth, can
compensate aberrations, and can tolerate deformations. We design a Cherenkov
plenoscope to explore timing by detecting low energetic gamma rays in large
areas.
