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While the Kepler Mission was designed to look at tens of thousands of faintstars (V > 12), brighter stars that saturated the detector are importantbecause they can be and have been observed very accurately by otherinstruments. By analyzing the unsaturated scattered-light `halo' around thesestars, we have retrieved precise light curves of most of the brightest stars inK2 fields from Campaign~4 onwards. The halo method does not depend on thedetailed cause and form of systematics, and we show that it is effective atextracting light curves from both normal and saturated stars. The keymethodology is to optimize the weights of a linear combination of pixel timeseries with respect to an objective function. We test a range of such objectivefunctions, finding that lagged Total Variation, a generalization of TotalVariation, performs well on both saturated and unsaturated K2 targets. Applyingthis to the bright stars across the K2 Campaigns reveals stellar variabilityubiquitously, including effects of stellar pulsation, rotation, and binarity.We describe our pipeline and present a catalogue of the 161 bright stars, withclassifications of their variability, asteroseismic parameters for red giantswith well-measured solar-like oscillations, and remarks on interesting objects.These light curves are publicly available as a High Level Science Product fromthe Mikulski Archive for Space Telescopes (MAST).

The K2 Bright Star Survey I: Methodology and Data Release