# Converting Star Chart Times For Your Locality

If you want to convert the above times for your locality in North America:

1. Find your longitude in degrees.
2. Subtract 86 from your longitude (if you are east of 86 degrees longitude, you will get a negative number).
3. Multiply the result by 4 giving the number of minutes correction. (If east of 86 degrees the correction will be negative)
4. From the last value subtract one hour for each time zone you are west of Eastern Time, or Add one hour for every time zone you are east of Eastern Time.
5. Add the result algebraically to the Grand Traverse region time. That is the time for the chart in your location.

Here's an example: for Aberdeen South Dakota

1. Longitude = 98
2. 98 - 86 = 12 degrees
3. 12 * 4 = 48 minutes
4. Aberdeen is in the Central time zone. The correction is -1 hour or -60 minutes. 48 - 60 = -12 (This is a constant for this location)
5. If the Grand Traverse region time is 9:00, then 9:00 - 0:12 = 8:48. The chart time for Aberdeen SD will be 8:48 p.m.

Corrections for latitude aren't as easy. The standard latitude for this chart is about 45 degrees. For latitudes farther north the sky shifts to the south, for latitudes farther south, the sky shifts to the north, revealing stars and constellations invisible from the Grand Traverse region.

Updated 07/09/98

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