HORIZON

        [ASTRO\]HORIZON h1 h2 ... [/AIRMASS] [/SOURCE ... ] [/PLANET  ...  ]
    [/FLUX Fmin Fmax] [/NIGHT_MARKS] [/ALTERNATE] [/PROJECT] [/ELEVATION]

    This  command  is  used to produce plots of LST ranges of observability,
    above specified elevations, of sources and planets. An OBSERVATORY and a
    TIME must have been selected. The LST axis is drawn on the bottom of the
    plot, and UTC on the top . An horizontal line is drawn for the time  pe-
    riod during which the object(s) is(are) visible above elevation h1; tick
    marks and labels are provided for elevations h1, h2, ...  (in  degrees),
    or  corresponding  air  masses  values (with /AIRMASS option). Elevation
    values must be in increasing order, or airmasses in decreasing order.

    Various options are available to control the plot:
        /SOURCE                  will plot all sources
                                 of the current (by default) or alternate
                                 (if /ALTERNATE is used) catalog.
        /SOURCE name1 name2 ...  will be restricted to the specified sources
                                 (sources are searched for in memory
                                 (after SOURCE command) or in the current
                                 catalog)
        /SOURCE NEXT n           will plot the next n sources in the current
                                 catalog (repeat this command to avoid over-
                                 crowded pages)
        /ALTERNATE               with /SOURCE, will use the Alternate catalog
        /FLUX Fmin Fmax          restrict the search to sources with flux in
                                 the specified range.

        /PLANET                  will plot on one page all solar-system bodies
        /PLANET name1 name2 ...  will be restricted to the specified bodies

        /NIGHT_MARKS             Plots also the beginning and end of astronomica
                                 nautical and civil twilights, and an estimate o
                                 the moon phase and the moon bolometric magnitud

    For specific Plateau de Bure scheduling purposes, the  options  /PROJECT
    and /ELEVATION can be used to further restrict the search of the sources
    in the catalog. In that case, the source catalog must have a  number  of
    additional  parameters available for each source (project name, frequen-
    cy, priority, minimal elavation,...).