The Swift Gamma-Ray Burst Explorer (Gehrels et al., 2004) is a NASA mission launched in 2004 to study Gamma-Ray Bursts (GRBs) and their afterglows. The X-ray Telescope (XRT) is a key component of the mission, designed to provide prompt, accurate X-ray observations of GRBs. The XRT uses a mirror set built for JET-X and an XMM-Newton/EPIC MOS CCD detector to achieve a sensitive, broad-band X-ray imager with an effective area of over 120 cm² at 1.5 keV, a field of view of 23.6×23.6 arcminutes, and an angular resolution of 18 arcseconds (HPD). It can detect sources as faint as 2×10⁻¹⁴ erg cm⁻² s⁻¹ in 10⁴ seconds and provides automated source detection and position reporting within 5 seconds of target acquisition. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize science return for each frame as the source intensity fades. It measures spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and follows each burst for days or weeks. The XRT uses a grazing incidence Wolter I telescope to focus X-rays onto a thermoelectrically cooled CCD. The instrument is designed to measure fluxes, spectra, and lightcurves of GRBs and afterglows over a wide dynamic range of more than 7 orders of magnitude in flux. The XRT has a 3.500m telescope focal length and an overall instrument length of 4.67m with a diameter of 0.51m. The XRT is designed to provide accurate positions within 5 seconds of target acquisition for typical bursts, allowing ground-based optical telescopes to begin immediate spectroscopic observations of the afterglow. The XRT has a 18 arcsecond (HPD) on-axis PSF at 1.5 keV and can detect X-ray line emission from GRB afterglows, which may be the result of thermal emission or X-ray reflection. The XRT has an energy resolution of about 140 eV at 6 keV and can measure redshifts of GRBs with Fe line emission or other spectral features. The XRT is designed for completely autonomous operation, switching between different readout modes according to the instantaneous count rate in each CCD frame. The XRT is also designed to provide accurate photometry and light curves with at least 10 ms time resolution. The XRT has a radiation-hardened CCD and is designed to operate in a low Earth orbit with a 600 km altitude and 22° inclination. The XRT is designed to provide accurate source positions and lightcurvesThe Swift Gamma-Ray Burst Explorer (Gehrels et al., 2004) is a NASA mission launched in 2004 to study Gamma-Ray Bursts (GRBs) and their afterglows. The X-ray Telescope (XRT) is a key component of the mission, designed to provide prompt, accurate X-ray observations of GRBs. The XRT uses a mirror set built for JET-X and an XMM-Newton/EPIC MOS CCD detector to achieve a sensitive, broad-band X-ray imager with an effective area of over 120 cm² at 1.5 keV, a field of view of 23.6×23.6 arcminutes, and an angular resolution of 18 arcseconds (HPD). It can detect sources as faint as 2×10⁻¹⁴ erg cm⁻² s⁻¹ in 10⁴ seconds and provides automated source detection and position reporting within 5 seconds of target acquisition. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize science return for each frame as the source intensity fades. It measures spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and follows each burst for days or weeks. The XRT uses a grazing incidence Wolter I telescope to focus X-rays onto a thermoelectrically cooled CCD. The instrument is designed to measure fluxes, spectra, and lightcurves of GRBs and afterglows over a wide dynamic range of more than 7 orders of magnitude in flux. The XRT has a 3.500m telescope focal length and an overall instrument length of 4.67m with a diameter of 0.51m. The XRT is designed to provide accurate positions within 5 seconds of target acquisition for typical bursts, allowing ground-based optical telescopes to begin immediate spectroscopic observations of the afterglow. The XRT has a 18 arcsecond (HPD) on-axis PSF at 1.5 keV and can detect X-ray line emission from GRB afterglows, which may be the result of thermal emission or X-ray reflection. The XRT has an energy resolution of about 140 eV at 6 keV and can measure redshifts of GRBs with Fe line emission or other spectral features. The XRT is designed for completely autonomous operation, switching between different readout modes according to the instantaneous count rate in each CCD frame. The XRT is also designed to provide accurate photometry and light curves with at least 10 ms time resolution. The XRT has a radiation-hardened CCD and is designed to operate in a low Earth orbit with a 600 km altitude and 22° inclination. The XRT is designed to provide accurate source positions and lightcurves