Astronomy Stack Exchange is a question and answer site for astronomers and astrophysicists. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am trying to determine the time of day of some images I have. I know the lat/lon, the day and year of image. I also know the 3 solar angles (zenith, azimuth, and elevation). Is there MATLAB or any other code that can do this calculation?


share|improve this question
Compare… – Gerald Feb 10 '14 at 20:45
Technically speaking, the answer to your question is "yes". You didn't ask HOW to do it ;) As a note, zenith and elevation are redundant (one is 90 degrees minus the other) unless I'm missing something. And, actually, you only need the azimuth to figure out time. should do the trick. – barrycarter Feb 10 '14 at 22:51
Depends how precise you want to be, though, as the Equation of Time has a role to play. But sundials are founded on this principle. – adrianmcmenamin Feb 11 '14 at 16:14

Of course it is! How do you think sundials work? That said, there are better, more precise ways to keep time. I don't know how to do it for an image; that is really a computational problem rather than an astronomy question. You might be better off asking it at Stack Overflow.

share|improve this answer

Yes, you can, and it is easy.

You only need a Nautical Almaniac.

You'll find there both the tables you need for the Equation of Time and the formulas to use.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.