The timeHeaderCellDuration property (number) sets the duration of the time header cells in minutes. By default, the JavaScript Calendar component uses a size that matches the grid cell size (see the "Auto" value).
"Auto" - sets the value to 60 minutes for scale values smaller than one hour; otherwise it matches the scale unit
number - uses the specified number of minutes
"Auto"Calendar config:
{
timeHeaderCellDuration: 30,
// ...
}