Create a chart with a LinesSeries with a DateTimeContinuousAxis axis and set the following properties:
DateTimeContinuousAxis horizontalAxis = new DateTimeContinuousAxis();
horizontalAxis.Title = tupleItem.HorizontalAxis;
horizontalAxis.AxisType = AxisType.First;
horizontalAxis.VerticalLocation = AxisVerticalLocation.Bottom;
horizontalAxis.AutomaticBorderColor = false;
horizontalAxis.MaximumTicks = 10;
horizontalAxis.LabelFormat = "{0:HH:mm:ss.fff}";

You will see that there are less labels than ticks.

When the chart is zoomed the labels also disappear from the ticks.