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Re: two issues with julian dates [message #54814 is a reply to message #54813]

Wed, 11 July 2007 15:25

Josh
Messages: 21
Registered: June 2007

Junior Member

On Jul 11, 3:58 pm, David Fanning <n...@dfanning.com> wrote:
> Josh writes:
>> I've got date and time strings that I've parsed into their respective
>> hour/minute/etc and month/day/etc form and I'm using the julday()
>> function to turn them into julian dates. I've come across two
>> problems that hopefully somebody can help me with.
>
>> First off, according to NASA (http://ssd.jpl.nasa.gov/tc.cgi#top), the
>> returned value of julday() is incorrect. When I use 11/18/2003 at
>> 16:14:43, I get 2452955.2 from IDL and 2452962.1768866 from NASA.
>> Thoughts?
>
>> Second, the fact that julday() only returns a value with ONE digit
>> after the decimal is not cool. If it returns a double floating point
>> value, shouldn't I be able to get 14 sig figs? The time scales in my
>> data set are such that I need that resolution. Thoughts?
>
> Humm. Are you using *this* IDL!
>
> IDL> print, julday(11, 18, 2003, 16, 14, 43), format='(F 20.10)
> 2452962.1768865748
>
> Cheers,
>
> David
>
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming:http://www.dfanning.com/
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Perhaps it is because it is getting late into the afternoon, but I
can't use that technique to stuff the new Julian date into a variable,
correct? If I want to just save that beautifully long number in an
array, how can I keep it formatted like that?

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[Message index]

		Re: two issues with julian dates By: Josh on Thu, 12 July 2007 13:25
		Re: two issues with julian dates By: David Fanning on Thu, 12 July 2007 12:51
		Re: two issues with julian dates By: David Fanning on Thu, 12 July 2007 12:32
		Re: two issues with julian dates By: Josh on Thu, 12 July 2007 11:02
		Re: two issues with julian dates By: Jean H. on Wed, 11 July 2007 15:43
		Re: two issues with julian dates By: David Fanning on Wed, 11 July 2007 15:37
		Re: two issues with julian dates By: news.qwest.net on Wed, 11 July 2007 15:36
		Re: two issues with julian dates By: Josh on Wed, 11 July 2007 15:25
		Re: two issues with julian dates By: David Fanning on Wed, 11 July 2007 14:58
		Re: two issues with julian dates By: Josh on Mon, 16 July 2007 15:11

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