  The early and complete temporal characterization of optical, fast, transient
sources requires continuous and multiband observations over different
timescales (hours to months). For time-domain astronomy, using several
telescopes to analyze single objects is the usual method, allowing the
acquisition of highly sampled light curves. Taking a series of images each
night helps to construct an uninterrupted chain of observations with a high
cadence and low duty cycle. Speed is paramount, especially at early times, in
order to capture early features in the light curve that help determine the
nature of the observed transients and assess their astrophysical properties.
However, the problem of rapidly extracting source properties (temporal and
color evolution) with a heterogeneous data set remains. Consequently, we
present Muphoten, a general and fast-computation photometric pipeline able to
address these constraints. It is suitable for extracting transient brightness
over multi-telescope and multiband networks to create a single homogeneous
photometric time series. We show the performance of Muphoten with observations
of the optical transient SN 2018cow (from 2018 June to 2018 July), monitored by
the GRANDMA network and with the publicly available data of the Liverpool
Telescope.
