  Tidal disruption events of stars by supermassive black holes have so far been
discovered months to years after the fact. In this paper we explore the short,
faint and hard burst of radiation is emitted at maximum compression, as a
result of shock breakout. The detection of this burst can be used to capture
tidal disruption events in real time. We verify that shock breakout from main
sequence stars produces radiation in the X-ray range, but find that it is
difficult to detect using all sky X-ray surveying telescopes. In the case of
shock breakout from red giants, most of the radiation is emitted in the UV and
visible range, which is significantly easier to detect. A similar burst of
UV/optical radiation will also be emitted by stars puffed by tidal heating from
a previous passage close to the central black hole. This radiation can be
detected by surveys like ZTF and LSST. We calculate detection rates for
different types of galactic nuclei. For the case of a very full loss cone we
predict a detection rate of once per month with LSST, whereas for the case of a
very empty loss cone we predict a rate of once per year with LSST. Evidence
from a recent tidal disruption event, ASASSN-14li, seems to favour a very full
loss cone, in which case LSST is expected to detect one such event every month.
