Observations of 1H1426+428 with the Whipple 10 m imaging atmospheric Cherenkov telescope

TeV γ-ray observations of 1H1426+428, an X-ray selected BL Lacertae object at a redshift of 0.129, are reported here. The X-ray spectrum appears to peak near 100 keV; if this is the peak of the synchrotron emission, then this AGN is a prime candidate for TeV γ-ray emission assuming a Compton-synchrotron model. During the 1999, 2000 and 2001 observing seasons, the source has been intensively studied with the Whipple 10m imaging atmospheric ˇCerenkov telescope. The average signal recorded over the 2000 observing season (March-June) was above the 4σ level. The differential flux at 430 GeV was 2.9 ± 1.1 x 10-11 cm-2 s-1 TeV-1 .