This directory contains sky brightness tables.

PARAMETERS:

    The following sky brightness parameters are used.

          title - Title used for labeling of output.
    description - Multiple lines of text used for documentation of output.
     tablescale - Factor by which to multiply the table values.
	  units - Units of sky brightness (currently not used).

TABLE:

    The sky brightness table has two or three columns.  The first column
    is wavelength in Angstroms.  The last column is the sky brightness
    in flux units of ers/s/cm^s/A/arcsec^2 (currently this is the only units
    allowed but in future other units will be added).  If there are
    only two columns then this sky brightness "spectrum" is used for all
    moon phases.  If there are three columns then the second column is
    the moon phase given between new moon (phase of 0) and full moon
    (phase of 14).  If no table is given then a sky brightness of 0
    is assumed.

    Note that users may specify a sky brightness table, usually as a
    two column flux calibrated "spectrum".

EXAMPLE

    # title = "CTIO sky brightness as a function of moon phase"
    # units = ergs/s/cm^2/A/arcsec^2

      3600  0 6.63797E-18
      4400  0 5.48524E-18
      5500  0 6.87303E-18
      6400  0 9.83901E-18
      7900  0 1.34297E-17
     24000  0 5.57523E-16
      3600  3 1.05170E-17
      4400  3 7.23239E-18
      5500  3 7.53758E-18
      6400  3 1.07888E-17
      7900  3 1.34297E-17
     24000  3 5.57523E-16
      3600  7 4.59085E-17
      4400  7 1.51104E-17
      5500  7 9.93574E-18
      6400  7 1.29707E-17
      7900  7 1.61454E-17
     24000  7 5.57523E-16
      3600 10 1.66694E-16
      4400 10 3.46180E-17
      5500 10 1.89324E-17
      6400 10 1.71019E-17
      7900 10 1.94116E-17
     24000 10 5.57523E-16
      3600 14 6.63797E-16
      4400 14 1.04558E-16
      5500 14 3.60735E-17
      6400 14 2.47186E-17
      7900 14 2.55972E-17
     24000 14 5.57523E-16

SYNTAX:

    Comment lines begin with '#' and can contain any text and can occur
    anywhere in the file, though normally found at the beginning.

    Parameters are comment lines with the form

	# <parameter> = <value>

    where whitespace is required between each field, <parameter> is a single
    word parameter name, and <value> is a single word value.  A quoted string
    is a single word so if the value contains whitespace it must be quoted.
    Any text following the value is ignored.

    The optional table is a multicolumn list of numeric values.  The list
    must be in increasing order in the independent columns.  Only 1D (two
    columns) and 2D (three columns) tables are currently supported.  2D
    tables must form a regular grid.  The table will be interpolated.
    Extrapolation outside of the table consists of the taking the nearest
    value; thus, a single line defines a constant value for all values of
    the independent variable.  If a "tablescale" parameter is specified
    then the table values are multiplied by this value.
