The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV γ-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.

The Very Energetic Radiation Imaging Telescope Array System (VERITAS) represents an important step forward in the study of extreme astrophysical processes in the universe. It combines the power of the atmospheric Cherenkov imaging technique using a large optical reflector with the power of stereoscopic observatories using arrays of separated telescopes looking at the same shower. The seven identical telescopes in VERITAS, each of aperture 10 m, will be deployed in a filled hexagonal pattern of side 80 m; each telescope will have a camera consisting of 499 pixels with a field of view of 3.5°. VERITAS will substantially increase the catalog of very high energy (E > 100 GeV) c-ray sources and greatly improve measurements of established sources. Ó

We present the discovery of >350 GeV gamma-ray emission from the BL Lacertae (BL Lac) object 1ES 2344+514 with the Whipple Observatory 10m gamma-ray telescope. This is the third BL Lac object detected at very high energies (VHE, E > 300 GeV), the other two being Markarian 421 (Mrk 421) and Mrk 501. These three active galactic nuclei are all X-ray selected and have the lowest known redshifts of any BL Lac objects currently identified. The evidence for emission from 1ES 2344+514 comes mostly from an apparent flare on 1995 December 20 (universal date) during which a 6σ excess was detected with an average flux of I(>350 GeV) = 6.6 ± 1.9 × 10 −11 photons cm −2 s −1 . This is approximately 63% of the VHE emission from the Crab Nebula, the standard candle in this field. Observations taken between 1995 October

We report a possible detection of TeV gamma rays from the Galactic center by the Whipple 10 m gammaray telescope. Twenty-six hours of data were taken over an extended period from 1995 through 2003 resulting in a total significance of 3.7 j. The measured excess corresponds to an integral flux of Ϫ8 1.6 # 10 ‫ע‬ 0.5 # above an energy of 2.8 TeV, roughly 40% of the flux from the10 (stat) ‫ע‬ 0.3 # 10 (sys) photons m s Crab Nebula at this energy. The 95% confidence region has an angular extent of about 15Ј and includes the position of Sgr A*. The detection is consistent with a point source and shows no evidence of variability.

1 Fred Lawrence Whipple Observatory, Harvard-Smithsonian CfA,