IMAGE_SAMPLING

        IMAGE_SAMPLING

    Define  a  sampling  grid  for use as input to SHORT_MODEL. The sampling
    grid is a regular rectangular grid large enough to cover the size of the
    input  sky image. It is better than Nyquist sampled, i.e. the pixel size
    is the beam width divided by POINT_PER_BEAM$. One grid point either pass
    through the sky image center or the reference pixel available in the sky
    image.

    To better mimic On-The-Fly observations the  grid  should  have  Nyquist
    sampling perpendicular to the scanning direction.

    The  grid  nod  positions are given in radian as offsets compared to the
    reference position of the sky image. The grid is duplicated by the  num-
    ber  of  Single-Dish  antenna simultaneously observing. The output table
    has the following format: Number of position x Number  of  antenna  x  2
    (Lambda and Beta coordinates).