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Light calculator (table form)

 

I made this calculator because I always want a paper with me on longer trips with times for sunrise/sunset, night, moonrise/set, etc. The output table is plain text, which can be copied into a text editing program and printed if needed. However, before printing, it needs to be converted in the text editing program to a monospaced font (Courier works fine) and downsized to fit on the page. The script with the moon calculations is courtesy of Peter Hayes, used with permission.

 

Definitions:

• Day:

• Sunrise/sunset:

• Civil twilight:

• Nautical twilight:

• Astronomical twilight:

• Night:

Solar latitude is more than -0.833°.*

Solar latitude is -0.833°.

Solar latitude is between -0.833° and -6°.

Solar latitude is between -6° and -12°.

Solar latitude is between -12° and -18°.

Solar latitude is below -18°.

 

* About 0.25° of this is due to the suns radius and about 0.6° is due to atmospheric refraction. Atmospheric refraction is the bending of light when it travels through our atmosphere, and close to the horizon it is about 0.6°. Since the sun is about 0.5° in diameter, it means that, when we see the bottom of the sun touching the horizon, the sun is in reality already below the horizon!

 

Year/month/day (today):

/ /

Latitude (°)*:

Longitude (°)**:

Time zone ***:

Days:

Daylight saving time:

* North of the equator is positive, south of the equator is negative.

** East of Greenwich is positive, west of Greenwich is negative.

*** Fill in the time zone relative to UTC (overview). Examples: Hawaii is -10, the UK is 0, CET is +1, New Zealand is +12.

 

||-------------------------------------------------------------------------------------------------------------------------------------||

||-------------------------------------------------------------------------------------------------------------------------------------||

||    DATE    ||NIGHT|       TWILIGHT        |  DAY  |       TWILIGHT        |NIGHT||              MOON *             ||     HOURS     ||

||            ||     | astr. | naut. | civil |       | civil | naut. | astr. |     || (-- = moon is up) ||phase bright||  day  | night ||

||------------||-----|-------|-------|-------|-------|-------|-------|-------|-----||-------------------||------------||-------|-------||

||-------------------------------------------------------------------------------------------------------------------------------------||

* Moon phase and moon brightness are the values calculated for noon and are thus average values for that day. The moon brightness is relative to an average full moon. This is only an approximate value and in no way an absolute value.