Sunrise and Sunset Times are Incorrect - SM2/SM2+

Song Meter SM2 Tips and Troubleshooting
Core Product
SM2/SM2+
Accessory

The Date and Time screen of your Song Meter SM2 displays incorrect times for sunrise and sunset. If your schedule references sunrise or sunset for start and end times, your schedule will also not run at the correct times.

Cause: Incorrect Latitude and Longitude

The SM2 uses your location to estimate when sunrise and sunset occur.

Solution

  1. On the SM2, go to Settings > Location.
  2. Enter numerical value for Latitude, then press Select to save the setting.
    Press Up to select northern latitudes and Down to select southern latitudes.
  3. Enter numerical value for Longitude, then press Select to save the setting.
    Press Up to select western longitudes and Down to select eastern latitudes.
  4. Go to Settings > Time and Date and confirm that the sunrise and sunset times are correct.

Cause: Incorrect Time Zone

The SM2's time zone setting must be set accurately in order the recorder to accurately calculate sunrise and sunset.

If your region uses daylight saving time or summer time, your time zone changes seasonally. If you want the SM2 to match local time, you must update the recorder's time zone to match your seasonal time zone.

Solution

  1. Confirm the time zone and UTC offset for your deployment location and date.
    Online resources such as timeanddate.com list the current time zone of most locations in the world.
    At Walden Pond in Concord, Massachusetts, USA, the time zone depends on the time of year:
    • From November to March, the time zone is Eastern Standard Time (EST), or UTC - 5:00.
    • From March to November, the time zone is Eastern Daylight Time (EDT), or UTC - 4:00.
  2. On the SM2, go to Settings > Location > Timezone.
  3. Enter your UTC offset, noting the + or - sign, and press Select to confirm the change.
  4. Go to Settings > Time and Date and confirm that the SM2's settings match the current date and time for your time zone.
  5. Confirm that the sunrise and sunset times on the Time and Date screen are correct.

Cause: Incorrect Date and Time

The time of sunrise and sunset shift throughout the year. The SM2's internal clock must be set correctly to accurate calculate sunrise and sunset.

Solution

  1. On the SM2, go to Settings > Time and Date.
  2. Use the arrow buttons to adjust the date and time, then press Select to confirm your changes.
  3. Check that the listed sunrise and sunset times are correct.

Cause: Incorrect Solar Calculation Method

The SM2 can be set to use one of four conventions to set the time of sunrise and sunset. If you have selected the wrong convention, the calculated sunrise and sunset time will not match what you expect. These conventions are based on the angle of the sun below the horizon.

Sunrise/Sunset
This is the default option.
When the upper visible edge of the sun is level with the horizon.
Civil Twilight
When the center of the sun is 6 degrees below the horizon.
Nautical Twilight
When the center of the sun is 12 degrees below the horizon.
Astronomical Twilight
When the center of the sun is 18 degrees below the horizon.

Solution

  1. On the SM2, go to Settings > Sunrise/Sunset Type.
  2. Select the convention you want to follow, and press Select to confirm the setting.
  3. Go to Settings > Time and Date and confirm that the sunrise and sunset times are correct.