You may wish to reference this thread, which shows:
val morning = now.withTimeAtStartOfDay.plusHours(5).millis // 5 AM
val sunrise = new DateTime((Sunrise_Time.state as DateTimeType).calendar.timeInMillis)
val twilight = new DateTime((Twilight_Time.state as DateTimeType).calendar.timeInMillis)
val night = now.withTimeAtStartOfDay.plusHours(23).millis // 11 PM
if(now.isAfter(morning) && now.isBefore(sunrise)) {
Morning.sendCommand(ON)
Day.sendCommand(OFF)
Twilight.sendCommand(OFF)
Night.sendCommand(OFF)
}