The CRABTIME database contains the Crab Pulsar Monthly Ephemeris covering the period from Feb 15 1982 (MJD=45015) to (close to) the present that was created Dr. Andrew Lyne and collaborators at Jodrell Bank Observatory. This database is periodically updated to include recent data as these become available. To assist astronomers, the HEASARC has created two new parameters which were not present in the original Jodrell Bank tables, the pulsar period and its first derivative, using the standard relations between period (P) and frequency 'Nu' (P=1./Nu) and their first derivatives (P_dot = -Nu_dot/Nu<sup>2</sup>). The assumed pulsar position used in the reductions is <pre> RA (1950.0) 05 31 31.406 DEC (1950.0) +21 58 54.391 RA (2000.0) 05 34 31.973 DEC (2000.0) +22 00 52.061 </pre> This HEASARC version of the "Jodrell Bank Crab Pulsar Timing Results, Monthly Ephemeris" is updated within one week of any changes to the tables available on the Web at <a href="http://www.jb.man.ac.uk/pulsar/crab.html">http://www.jb.man.ac.uk/pulsar/crab.html</a>;. This is a service provided by NASA HEASARC .
