(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I need to calculate the length of daylight and all of my answers are about 15 minutess too long according to actual data on the web. Can someone give me insight as to why the equation is off by this much?

2. Relevant equations

Daylight=2[cos-1(-tan(latitude degree)tan(declination angle degree))]

3. The attempt at a solution

For example, the length of day at latitude 80 degrees on February 1st, which should be zero, works out to 0.244 hours or 15 minutes. Declination angle is calculated to be -17.9 degrees. Maybe that's the problem? Thanks for any help.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Why daylight equation is 15 minutes off

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**