The time zone offset can be set to ZERO for any place on earth.  Just enter UTC time and date into the Hand Controller or Web interface instead of Local time and date. This way, the Gemini-2 will calculate everything from the UTC time (which it does anyway )  along with Latitude and Longitude.   The offset is only used so the Gemini-2 can calculate the correct UTC time from your local time.  This way, you never have to worry about daylight saving time effecting the calculations. NOTE: The time offset can be in decimal parts for the people that live in half or quarter time zones. Some places/countries use time offsets not an integral number of hours from UTC/GMT.  Just enter Hours : Minutes for the offset. Afghanistan offset from UTC is +04:30 Australia (Northern Territory)  offset from UTC is +09:30 Australia (South Australia)  offset from UTC is +09:30 (summer +10:30) Burma (Myanmar)  offset from UTC is + 06:30 India offset from UTC is +05:30 Iran  offset from UTC is +03:30 (summer +04:30) Lord Howe Island (Australia) offset from UTC is +10:30 (summer +11:00) Marquises Islands offset from UTC is -09:30 Norfolk Isl. (Australia) offset from UTC is +11:30 Newfoundland (Canada)  offset from UTC is UTC/GMT -03:30 (summer -02:30) Sri Lanka offset from UTC is +05:30 Some places use quarter / hour offset from UTC/GMT. Chatham Island (New Zealand) offset from UTC is +12:45 (summer +13:45 or winter in the northern hemisphere). Nepal  offset from UTC is +05:45 Western Australia, Eyre Highway towns: Eucla, Caiguna, Madura, Mundrabilla and Border Village (South Australia)  offset from UTC is +08:45 Usual Daylight Saving Time (Summer time) rule is- altering the clocks ahead by one hour. However there are exceptions: Lord Howe Island (Australia) advances its clocks by half an hour in the summer. Lord Howe Island is UTC +10:30 during local winter and UTC +11:00 during local summer. Arizona and Hawaii in the United Stated do not observe Daylight saving time at all.