Detection capability of ground-based meter-sized telescopes for shallow exoplanet transits

Meter-sized ground-based telescopes are frequently used today for the follow-up of extrasolar planet candidates. While transit signal a Jupiter-sized object can typically be detected to high level confidence with small telescope apertures as well, shallow dips planets size Neptune and smaller more challenging reveal. We employ new observational data illustrate photometric capabilities meter-sized exoplanet transits. describe in detail capability distinguishing an from underlying trend light curve. The depths six targets we observed, Kepler-94b, Kepler-63b, K2-100b, K2-138b, K2-138c, K2-138e, range 3.9 ppt down 0.3 ppt. For five this sample, provide first follow-up. detect or rule out features significantly single observations that show transits 1.3 deeper. shallower two 0.6 0.8 were tentatively curves, by repeated observations. Only target shallowest depth unable draw significant conclusion despite combining individual curves. An injection-recovery test on our real shows curves if is fully covered, including out-of-transit toward both sides, some cases 0.7 depth. able verify ephemeris. In case K2-138c deep transit, refine it, ruled time interval than +-1.5 sigma its current literature