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From: billa@sci.UUCP (Bill Ames)
Newsgroups: net.sources.bugs
Subject: Re: Planet2.c
Message-ID: <140@sci.UUCP>
Date: Mon, 13-Jan-86 12:05:31 EST
Article-I.D.: sci.140
Posted: Mon Jan 13 12:05:31 1986
Date-Received: Fri, 17-Jan-86 00:55:24 EST
References: <718@inuxe.UUCP>
Distribution: net
Organization: Silicon Compilers, Inc., San Jose, CA
Lines: 19
Summary: minor bug in planet2.c


There is a minor bug in Fred Mendenhall's planet2.c program.
It treats the 24-hour time as though 1250 was 12.5 hours instead
of 12 + 50/60.

The following correction to the day calculation fixes it:

    int hour,day;

    ...

    hour   = (int)(time/100);
    minute = time - hour*100;
    day    = (double)dd + ((double)(hour+tz+minute/60.0))/24.0;

This makes example 3.a in Meeus's book (page 24) come out right, and
changes the ultimate locations of the planets by a small amount.

Bill Ames, Silicon Compilers Inc