Re: Julian Day Numbers

["J.D. Smith" <jdsmith(at)astro.cornell.edu>]

Craig Markwardt wrote:
> 
> Hi Ben--
> 
> You need to be careful with your notations.  Jan 1, 1900, 12noon, is
> different from Jan 0, 1900, 12noon.  In fact, Jan 0 is the same as Dec
> 31 of the previous year, since we normal humans start our
> day-numbering system with 1.  So in fact the IDL JULDAY function is
> operating correctly.
> 
> There are a lot of astronomy-related julian date calculators which can
> be found on the U of W search page.  You might trust these a little
> more than RSI's since they are used by real scientists :-) I have my
> own which I can send along if desired.  However they all will still
> give 2415021 for the example you reported.

I see no reason to malign the IDL version of julday.  This is a pretty
simple calculation.  Perhaps we should concentrate our frustrations on
meatier IDL shortcomings.  We could burn a z-buffer in effigy.

JD

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