Plot small pieces of stellar occultation data. This procedure is intended to be used in plotting a very large 1-d vector as a function of time in which you are only interested in plotting a small subset of the data. The time calibration is specified through the tstart and dt input parameters and the time axis is assumed to be strictly linear. All time calculations are done in double precision to ensure the full precision of the time axis is saved.
Single precision gives out at the few millisecond level.
The current plotting device is used for output. If not supplied the plot runs from the max to the min of the portion plotted. If yspan is two-element vector, the two values are used as the actual yrange on the plot. When set, the points are connected by a line. When set, the plot is done as an overlay on the current plot.