How to Change Your Location and Time Zone

From the Combined View (the dual-pane screen with the circular chart on the right and the rectangular window at upper left), click the CHANGE button in the Location display area toward the lower left of the screen. This will take you to the Choose Location page:

All locations:

Be sure to enter data in just one of the three sections of this page: USA or Canada, World by City, or Worldwide by Latitude & Longitude. If you want to make the new location your default observing location, click the checkbox provided for that purpose. If you don't check the box, the new location will be used for this session only.

USA or Canada:

The simplest way to enter your location, and the approach recommended for first-time users, is to enter your Zip code (USA) or postal code (Canada) and choose USA or Canada from the country pull-down menu. When you click the SUBMIT button, the system will use this information to determine your city, state or province, latitude, and longitude.

If you enter your location by specifying a city, be sure to choose the corresponding entry from the state/province pull-down menu too, as well as the country (USA or Canada) from the country pull-down. Click the SUBMIT button. If the system can't find your city, or if you get a page listing several possible matches with the same city name but different geographic coordinates (latitudes and longitudes), go back and try entering a nearby city with a more unusual name. The Sky Chart's accuracy will not be compromised as long as the city or town you choose as your observing location is no more than 10 kilometers (6 miles) from your actual location.

Alternatively, if you have a good map or atlas handy, you could instead estimate your latitude and longitude and choose the best match to those coordinates from the list of multiple cities with the same name.

World by City:

Enter the name of your city or town, select your country from the pull-down menu, and click the SUBMIT button. If the system can't find your city in our database, try entering a common alternative spelling of the name, if any. If that doesn't work either, try entering the name of a larger city nearby.

If the information you enter causes the system to come up with several possible matches with identical city names but different latitudes and longitudes, follow the instructions in the USA or Canada section above.

Worldwide by Latitude & Longitude:

If you know your latitude and longitude or can find them using a high-resolution map or Global Positioning System (GPS) receiver, enter them in the spaces provided. All entries should be positive numbers. Degrees of latitude should fall between 0 and 90, minutes between 0 and 60; be sure to specify north (N) or south (S) using the radio buttons. Degrees of longitude should fall between 0 and 180, minutes between 0 and 60; be sure to specify east (E) or west (W). For reference, in North America latitudes are N and longitudes W, while in Australia latitudes are S and longitudes E. If in doubt, choose your location using one of the methods described above instead.

Once you have successfully entered your location, you'll see the Choose Time Zone screen:

Note that you cannot get to the Choose Time Zone screen directly from the Combined View, All-Sky Chart, or Selected View — you must go through the Choose Location screen first.

First verify that the location displayed there is correct. If it isn't, click on the Change Location link to return to the Choose Location page. Otherwise, select the time zone appropriate to your location from the pull-down menu. The system will not check whether your time-zone selection matches your location. If you're unsure of the time zone for the location you've selected, you may be able to figure it out using SwissInfo.net's Local Times Around the World page. Don't forget to check the Daylight Saving Time box if appropriate. Then click the SUBMIT button; you'll be returned the Combined View, where you'll see a depiction of the sky for the location you've selected.