Description:
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I have discovered https://bugs.php.net/bug.php?id=49448 this bug report filed 
several years ago which, quite correctly, points out that php's default zenith 
is 90 + 35/60.

However, the official algorithm from the 1990 Almanac for Computers published by 
the Nautical Almanac Office at the United States Naval Observatory (which can be 
found at http://williams.best.vwh.net/sunrise_sunset_algorithm.htm) quite 
clearly says that the correct value is 90+50/60.

The old bug was closed as bogus with a message saying that "the algorithm code 
we use clearly says 35/60". That statement is nothing more than a tautology. It 
says "the code should be 35/60 because if you look at the code, it says 35/60", 
and does nothing to answer where this value came from, or why it differs from 
the canonical value. Some commenters had noted this, but there was no response.

As such, I'd like to reopen this bug and see it correctly fixed, rather than 
simply swept under the carpet.

Test script:
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echo ini_get("date.sunset_zenith"), "\n", ini_get("date.sunrise_zenith"), "\n", (90 + 50/60), "\n";

Expected result:
----------------
90.833333333333
90.833333333333
90.833333333333

Actual result:
--------------
90.583333
90.583333
90.833333333333