HEADER /TELESCOPE

        [VECTOR\]HEADER GildasFile|HeaderVariable /TELESCOPE [+-]Tel1

    This  option  adds  (leading +) or removes (leading -) one or more tele-
    scope from the telescope section. If the + or - character is omitted,  +
    is assumed.

    For example:
      SIC> HEADER myfile.gdf /TELESCOPE 30M
    adds the 30M to the telescope section.
      SIC> HEADER myfile.gdf /TELESCOPE -ALMA +ACA
    removes the ALMA telescope and adds ACA.

    It  is not an error to add a telescope already present, and it is not an
    error to remove a telescope already absent.