Astronomical Applications Department, U.S. Naval Observatory NOVAS 2004 Overview Page 7
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given date in one of two ways. In high-accuracy mode, the values are read and interpolated from an
external file (output from a numerical integration), which covers years 1700 to 2300. In low-accuracy
mode, the values are obtained from a 16-term series valid from 1850 to 2150. NOVAS will generate
an error message if you request dates outside these ranges or if it cannot find the external file (in high-
accuracy mode). The path/name of the external file, its type (sequential or direct-access), and the
logical unit number on which it is to be read can be specified in a call to CEOFIL, which obviously
must precede any CEO-based computation. If CEOFIL is not called, NOVAS will assume that there is
a formatted sequential file named CEO_RA.TXT in the current directory (folder) and will read it on
logical unit 24. A copy of CEO_RA.TXT is available in the NOVAS directory (7.5 Mbytes), along
with a utility program called CEO_file.f to convert it to a binary direct-access file (2.9 Mbytes) if
desired. Existing NOVAS programs, unless specifically modified, will not use the CEO-based
paradigm for Earth rotation and will not need any version of this file.
