  We have produced an atlas of the Th-Ar hollow-cathode lamp used with the
2dcoude spectrograph at McDonald Observatory. The atlas covers from 3611.9 to
10596.4 A at a resolving power of 52,000. We have determined the wavelenghts of
1483 emission lines in the spectrum with a median precision of 0.00023 A. A
web-based interface is offered for interactive visualization of segments of the
atlas or spectral orders.
