Finding your Latitude/ Longitude

In order to report your observation of the night sky, you will need to know the latitude and longitude (lat/long) of your location.

What are latitude and longitude?

Latitude is your distance North or South from Earth’s equator, measured in degrees. 0° is the latitude at the equator, +90° is the latitude at the North Pole, and -90° is the latitude at the South Pole. Longitude is your distance East or West of the Prime Meridian, which runs from the North Pole to the South Pole through Greenwich, England. The Prime Meridian is at 0°. Moving East, longitude increases from 0° to +180°. Moving West, longitude goes from 0° to -180°. (Note: +180° and 180° are the same longitude line).

General Location Latitude Longitude
Europe & Asia North, + East , +
North America North, + West, -
Australia & New Zealand South, - East , +
South America South , - West , -

There is an interactive latitude/longitude locator on the “Report” page (also known as the “Webapp”) when you enter your observation. You can use it to manually enter your location or have it automatically use your smart device’s current location.

If you want to determine your location before making your observations, you can also use a GPS unit or a smart phone at the observation site. Be sure to report as many decimal places as the unit provides.

Frequently Asked Questions about Determining Location

“I have a GPS receiver or can borrow one. How do I determine my location?”

Take the GPS outside to the location you where you are observing, and turn it on. In a few seconds, the GPS will display the coordinates. Most receivers will display the coordinates in either “Degrees, Minutes, Seconds” or “Decimal Degrees”. If you have a choice, select Decimal Degrees. You may need to refer to the User’s Manual to set the display. Be sure you understand which number is latitude and which is longitude! When you record your location, it is critical to write down all the decimal places (usually, there will be 4 or 5 decimal places).

“I don’t have a GPS, but I know the street address. What should I do?” See below.

“I don’t know the street address, but I know one nearby.” See below.

“I want to observe in a remote location, and there aren’t any addresses nearby.”

All of these situations can be handled by the new Globe at Night Webapp. In the second section of the app is a map that takes a variety of inputs. If you are using a GPS enabled device, such as a cell phone or tablet, the map will ask to use your location to locate where you are on the map. On any device (including a computer), you can input an address, and the map will center on that address. You can further refine your location by panning the map and clicking (or touching) your location to place a marker. The app reports the latitude and longitude of the marker.