... Latitude can be deduced from the height above the horizon of the pole star or of the noontime Sun, while longitude requires an accurate clock giving universal time. ... This lesson plan supplements: "Navigation," section #5a: on disk Snavigat.htm , on the web . ... Understand how finding one's local longitude requires comparing local time (e.g. local noon, when the Sun is at its highest above the horizon), with universal time, (UT). ... How can the noontime Sun give you your latitude ?? ...