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Table 2

Additional units allowed within OGIP datasets & software

  Quantity          Unit        Meaning		       Notes
                    String

plane angle deg degree of arc 1.745533 x 10-2 rad arcsec second of arc 4.848137 x 10-6 rad arcmin minute of arc 2.90888 x 10-4 rad time min minute (incl sidereal time if appropriate) h hour (incl sidereal time if appropriate) d day 8.64 x 104 s yr year (Julian) 3.15576 x107 s (365.25 d) energy + eV electron volt 1.602177 x 10--19 J erg erg 10-7 J length angstrom angstrom 10-10 m AU astronomical unit 1.49598 x 1011 m lyr light year 9.460530 x 1015 m + pc parsec 3.0857 x 1016 m events count counts photon photons flux density + Jy jansky 10-26 W m-2 Hz-1 mag (stellar) magnitude (see text) + Crab 'crab' (see text) magnetic field G gauss 10-4 T area pixel (image/detector) pixel barn barn 10-28 m2 Miscellaneous 'units' chan (detector) channel bin numerous applications (including the 1-d analog of pixel) voxel 3-d analog of pixel byte (computer) byte + - addition of prefixes for decimal multiples & submultiples are allowed (see Section 2.3)



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