The Prime Meridian at Greenwich, London is the reference for every time zone in the world.
What is Greenwich Mean Time (GMT)?
United Kingdom is now on GMT
Northern Territory is on Australia Central Standard Time (ACST).
ACST is 9.5 hours ahead of Greenwich Mean Time (GMT+9.30).
Daylight Saving (Summer) Time is not observed in Northern Territory.
The international dialling code for Northern Territory is +618.
Government of Northern Territory website : www.nt.gov.au